Pub Date : 2025-11-11DOI: 10.1016/j.ijimpeng.2025.105591
Zejian Xu , Zhicheng Cai , Yang Han , Liudmila Igusheva , Yuri Petrov , Shixiang Zhao , Fenglei Huang
The split Hopkinson pressure bar (SHPB) system and a universal testing machine were used to measure the fracture toughness of zirconia (ZrO2) and alumina (Al2O3) ceramics across a wide range of loading rates from 1.0 × 10-8 to 2.0 TPa·m1/2·s-1. The experimental-numerical method was used to determine the dynamic fracture toughness of the materials. The results exhibit a positive relationship between fracture toughness and loading rate as well as a negative correlation between fracture initiation time and loading rate for both of the ceramics. The analysis of fracture morphology reveals different micromechanism in the failure of the materials under different loading rates. This analysis offers an explanation for the dependency of fracture toughness on loading rates. Additionally, the incubation time criterion and its modified version were employed to describe the effects of loading rate on fracture toughness and fracture initiation time.
{"title":"Fracture toughness and failure mechanism of alumina and zirconia ceramics over a wide loading rate range","authors":"Zejian Xu , Zhicheng Cai , Yang Han , Liudmila Igusheva , Yuri Petrov , Shixiang Zhao , Fenglei Huang","doi":"10.1016/j.ijimpeng.2025.105591","DOIUrl":"10.1016/j.ijimpeng.2025.105591","url":null,"abstract":"<div><div>The split Hopkinson pressure bar (SHPB) system and a universal testing machine were used to measure the fracture toughness of zirconia (ZrO<sub>2</sub>) and alumina (Al<sub>2</sub>O<sub>3</sub>) ceramics across a wide range of loading rates from 1.0 × 10<sup>-8</sup> to 2.0 TPa·m<sup>1/2</sup>·s<sup>-1</sup>. The experimental-numerical method was used to determine the dynamic fracture toughness of the materials. The results exhibit a positive relationship between fracture toughness and loading rate as well as a negative correlation between fracture initiation time and loading rate for both of the ceramics. The analysis of fracture morphology reveals different micromechanism in the failure of the materials under different loading rates. This analysis offers an explanation for the dependency of fracture toughness on loading rates. Additionally, the incubation time criterion and its modified version were employed to describe the effects of loading rate on fracture toughness and fracture initiation time.</div></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":"209 ","pages":"Article 105591"},"PeriodicalIF":5.1,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145528628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Firstly, the damage test of the torpedo head scale model under the underwater explosion of 45gTNT was carried out. The test results showed that when the explosion distance was 50 cm, 20 cm and 15 cm, the torpedo head presented mild damage, moderate damage and severe damage respectively. Then, tests were carried out on the mechanical properties of the torpedo shell material. For A356 aluminum alloy, the effect of Lode angle is introduced into the Johnson-Cook (JC) fracture criterion, so that a fracture criterion considering Lode parameter, stress triaxiality, strain rate, and temperature is proposed, and the parameters are determined based on the simple tensile, notched tensile, shear, dynamic tensile, and high temperature tensile. Then the Johnson-Cook constitutive model was modified by correcting the strain-hardening term based on the Hockett-Sherby hardening model, correcting the strain-rate term by using the bifold model, and adding a parameter to the temperature term, thus proposing a modified JC constitutive model, and the parameters of the JC constitutive model were determined by static and dynamic compression experiments. And the causes of thermal softening at different temperatures were analyzed through electron microscope scanning. Then the plastic work transfer coefficient was determined based on single pulse loading experiments, and 2.5gTNT underwater explosion experiments were carried out in different blast distances of the thin plate. Through the fracture criterion and the constitutive model proposed in this paper, and JC fracture criterion to carry out numerical simulations and comparisons found that: due to the JC fracture criterion does not take into account the influence of the Lode parameter, the results of its simulation is more serious than the experimental damage. The proposed fracture model and constitutive model can simulate the damage in the experiment better than JC model. Finally, numerical simulation of the head damage of the torpedo was carried out. The failure mode of the torpedo shell, as well as the variation process of plastic strain and temperature during the explosion process, were discussed.
{"title":"Application of the MJC model considering the Lode effect and temperature effect in the study of torpedo damage caused by underwater explosions","authors":"Yanbo Wen, Qu Wang, Ying Ye, Zhichao Lai, Chenyang He, Yipeng Jiang, Ruiyuan Huang","doi":"10.1016/j.ijimpeng.2025.105590","DOIUrl":"10.1016/j.ijimpeng.2025.105590","url":null,"abstract":"<div><div>Firstly, the damage test of the torpedo head scale model under the underwater explosion of 45gTNT was carried out. The test results showed that when the explosion distance was 50 cm, 20 cm and 15 cm, the torpedo head presented mild damage, moderate damage and severe damage respectively. Then, tests were carried out on the mechanical properties of the torpedo shell material. For A356 aluminum alloy, the effect of Lode angle is introduced into the Johnson-Cook (JC) fracture criterion, so that a fracture criterion considering Lode parameter, stress triaxiality, strain rate, and temperature is proposed, and the parameters are determined based on the simple tensile, notched tensile, shear, dynamic tensile, and high temperature tensile. Then the Johnson-Cook constitutive model was modified by correcting the strain-hardening term based on the Hockett-Sherby hardening model, correcting the strain-rate term by using the bifold model, and adding a parameter to the temperature term, thus proposing a modified JC constitutive model, and the parameters of the JC constitutive model were determined by static and dynamic compression experiments. And the causes of thermal softening at different temperatures were analyzed through electron microscope scanning. Then the plastic work transfer coefficient was determined based on single pulse loading experiments, and 2.5gTNT underwater explosion experiments were carried out in different blast distances of the thin plate. Through the fracture criterion and the constitutive model proposed in this paper, and JC fracture criterion to carry out numerical simulations and comparisons found that: due to the JC fracture criterion does not take into account the influence of the Lode parameter, the results of its simulation is more serious than the experimental damage. The proposed fracture model and constitutive model can simulate the damage in the experiment better than JC model. Finally, numerical simulation of the head damage of the torpedo was carried out. The failure mode of the torpedo shell, as well as the variation process of plastic strain and temperature during the explosion process, were discussed.</div></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":"209 ","pages":"Article 105590"},"PeriodicalIF":5.1,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145529215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-11DOI: 10.1016/j.ijimpeng.2025.105588
Moujin Lin , Guangzhao Pei , Lu Zhang , Bing Xue , Xuming Yan , Ao Ma
The mechanical response of materials under dynamic combined compression-shear loading is critical for many engineering applications. This study proposes a technique that utilizes a helical structure to convert axial compression waves into coupled compression–shear waves, thereby achieving synchronized dynamic loading in a conventional Split Hopkinson Pressure Bar (SHPB). A predictive formula was derived from stress wave theory to determine the shear-to-compressive stress ratio in the transmission bar. Finite element simulations were conducted to investigate the influence of key geometric parameters of the helical structure on the stress conversion. The results indicate that the number of helical rods has a negligible influence, whereas the lead angle and interfacial friction significantly affect the amplitudes of the transmitted stresses. Experimental validation demonstrated strong consistency with both theoretical predictions and numerical simulations, confirming the reliability of the proposed model. The developed technique offers precise control of loading synchronization and stress ratios, while maintaining the advantages of simplicity, reusability, and low cost. Furthermore, the dynamic mechanical behavior of 1060 Al was characterized, validating the effectiveness of the proposed experimental method.
{"title":"Achieving synchronous compression-shear loading on SHPB using helical structures","authors":"Moujin Lin , Guangzhao Pei , Lu Zhang , Bing Xue , Xuming Yan , Ao Ma","doi":"10.1016/j.ijimpeng.2025.105588","DOIUrl":"10.1016/j.ijimpeng.2025.105588","url":null,"abstract":"<div><div>The mechanical response of materials under dynamic combined compression-shear loading is critical for many engineering applications. This study proposes a technique that utilizes a helical structure to convert axial compression waves into coupled compression–shear waves, thereby achieving synchronized dynamic loading in a conventional Split Hopkinson Pressure Bar (SHPB). A predictive formula was derived from stress wave theory to determine the shear-to-compressive stress ratio in the transmission bar. Finite element simulations were conducted to investigate the influence of key geometric parameters of the helical structure on the stress conversion. The results indicate that the number of helical rods has a negligible influence, whereas the lead angle and interfacial friction significantly affect the amplitudes of the transmitted stresses. Experimental validation demonstrated strong consistency with both theoretical predictions and numerical simulations, confirming the reliability of the proposed model. The developed technique offers precise control of loading synchronization and stress ratios, while maintaining the advantages of simplicity, reusability, and low cost. Furthermore, the dynamic mechanical behavior of 1060 Al was characterized, validating the effectiveness of the proposed experimental method.</div></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":"209 ","pages":"Article 105588"},"PeriodicalIF":5.1,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145579409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-11DOI: 10.1016/j.ijimpeng.2025.105589
Mario Scholze , Luisa Schottstedt , Maximilian Hinze , Philipp Frint , Martin F.-X. Wagner
Formation of adiabatic shear bands (ASB) as a deformation mechanism occurs particularly at high (shear) strain rates in metallic materials. A detailed analysis of ASB nucleation and growth, and of the contributions of the underlying mechanisms such as thermal or microstructural softening, is experimentally challenging. In this study, we present newly designed S-shaped sample geometries that allow an in-situ characterization of shear banding under different stress states. Local shear deformation occurs in a geometrically well-defined shear zone during uniaxial compression of the S-shaped samples. Considering both numerical simulations and experimental measurements, we demonstrate that the predominant shear stress can be superimposed with either tensile or compressive stresses by slightly varying the geometry of the shear zone. Moreover, we show that the sample geometry is ideally suited for the application of digital image correlation for strain (rate) mapping as well as temperature measurements at high loading velocities. Metallographic preparation of the samples prior to testing enables in-situ microstructural observations during dynamic deformation. The sample geometry is validated by dynamic experiments using a Ti-10V-2Fe-3Al alloy in a Split-Hopkinson Pressure Bar (SHPB) under nominal strain rates of >103 s-1 (which corresponds to local shear rates up to 105 s-1). Our experimental and numerical results demonstrate that the novel sample geometry facilitates detailed investigations focused on the formation and growth of adiabatic shear bands.
{"title":"Tailored planar S-shaped samples for in-situ characterization of adiabatic shear banding under controlled stress triaxialities","authors":"Mario Scholze , Luisa Schottstedt , Maximilian Hinze , Philipp Frint , Martin F.-X. Wagner","doi":"10.1016/j.ijimpeng.2025.105589","DOIUrl":"10.1016/j.ijimpeng.2025.105589","url":null,"abstract":"<div><div>Formation of adiabatic shear bands (ASB) as a deformation mechanism occurs particularly at high (shear) strain rates in metallic materials. A detailed analysis of ASB nucleation and growth, and of the contributions of the underlying mechanisms such as thermal or microstructural softening, is experimentally challenging. In this study, we present newly designed S-shaped sample geometries that allow an in-situ characterization of shear banding under different stress states. Local shear deformation occurs in a geometrically well-defined shear zone during uniaxial compression of the S-shaped samples. Considering both numerical simulations and experimental measurements, we demonstrate that the predominant shear stress can be superimposed with either tensile or compressive stresses by slightly varying the geometry of the shear zone. Moreover, we show that the sample geometry is ideally suited for the application of digital image correlation for strain (rate) mapping as well as temperature measurements at high loading velocities. Metallographic preparation of the samples prior to testing enables in-situ microstructural observations during dynamic deformation. The sample geometry is validated by dynamic experiments using a Ti-10V-2Fe-3Al alloy in a Split-Hopkinson Pressure Bar (SHPB) under nominal strain rates of >10<sup>3</sup> s<sup>-1</sup> (which corresponds to local shear rates up to 10<sup>5</sup> s<sup>-1</sup>). Our experimental and numerical results demonstrate that the novel sample geometry facilitates detailed investigations focused on the formation and growth of adiabatic shear bands.</div></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":"212 ","pages":"Article 105589"},"PeriodicalIF":5.1,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-10DOI: 10.1016/j.ijimpeng.2025.105586
Xiongwen Jiang , Yu Tang , Wei Zhang , Jun Wang , Yanjie Zhao , Lunping Zhang , Wenwei Wu
The safety of ship structures under underwater explosions depends on their stiffness and strength. The coupled loads of underwater shock waves and fragments can cause severe deformation and damage to the structures. To accurately assess this situation, a novel underwater shock wave and fragment coupled load testing system (SF-CLTS) has been developed by modifying the gas gun system. By controlling the time difference of the launching system as well as the velocities of the flyer and bullet, the time interval of the coupled loads can be adjusted. The deformation process of the target plate can be visualized using the 3D digital image correlation (3D-DIC) method combined with images captured by high-speed cameras. The dynamic deformation and damage of aluminum alloy plates under the aforementioned loads were studied by means of SF-CLTS. Meanwhile, the theoretical analysis of the impact process between the thin plate and the fluid was carried out using the energy method and the plastic hinge-spring model, with supplementary and comparative analysis using experimental data. This revealed the correlation between structural deformation and the intensity of external shock waves (peak pressure and exponential decay time). This method is crucial for the safety assessment and design of ship structures, and helps to deepen our understanding of the complex impact effects of underwater explosions.
{"title":"Investigation on the underwater explosion coupled loads testing technique and deformation response of thin plate subjected to underwater shock and fragments","authors":"Xiongwen Jiang , Yu Tang , Wei Zhang , Jun Wang , Yanjie Zhao , Lunping Zhang , Wenwei Wu","doi":"10.1016/j.ijimpeng.2025.105586","DOIUrl":"10.1016/j.ijimpeng.2025.105586","url":null,"abstract":"<div><div>The safety of ship structures under underwater explosions depends on their stiffness and strength. The coupled loads of underwater shock waves and fragments can cause severe deformation and damage to the structures. To accurately assess this situation, a novel underwater shock wave and fragment coupled load testing system (SF-CLTS) has been developed by modifying the gas gun system. By controlling the time difference of the launching system as well as the velocities of the flyer and bullet, the time interval of the coupled loads can be adjusted. The deformation process of the target plate can be visualized using the 3D digital image correlation (3D-DIC) method combined with images captured by high-speed cameras. The dynamic deformation and damage of aluminum alloy plates under the aforementioned loads were studied by means of SF-CLTS. Meanwhile, the theoretical analysis of the impact process between the thin plate and the fluid was carried out using the energy method and the plastic hinge-spring model, with supplementary and comparative analysis using experimental data. This revealed the correlation between structural deformation and the intensity of external shock waves (peak pressure and exponential decay time). This method is crucial for the safety assessment and design of ship structures, and helps to deepen our understanding of the complex impact effects of underwater explosions.</div></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":"209 ","pages":"Article 105586"},"PeriodicalIF":5.1,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145579279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-10DOI: 10.1016/j.ijimpeng.2025.105587
Zhi-yong Yin , Qi-guang He , Xiao-wei Chen
Fragmentation analysis in explosively driven cylindrical shells is crucial for weapon development and structural protection. To evaluate the overall response of protective structures to explosive fragments, it is essential to clarify the spatial distribution characteristics of the fragments. This study investigates the influence of fracture mode on fragment morphology and spatial distribution through numerical simulations, highlighting the non-uniform fragment distribution. A damage analysis method based on the kinetic energy of fragments is proposed, which illustrates both the spatial distribution and energy concentration in specific areas. The results reveal that the kinetic energy distribution of fragments exhibits a clustering effect only in shear fracture, corresponding to the elongated fragments generated from the middle of the cylindrical shell. Furthermore, a theoretical model is developed to determine the maximum kinetic energy angle, facilitating the rapid identification of severely damaged regions in protective structures. The experimental results validate the non-uniform distribution of perforation areas on witness plates and demonstrate that the theoretical model can accurately predict the location and extent of severe damage under varying conditions. This study provides an energy-based theoretical framework for damage assessment of explosive fragments, offering valuable insights for damage and protection design in fields such as the ship damage evaluation and the blast resistance of concrete structures.
{"title":"Spatial distribution and damage prediction of explosive fragments in cylindrical shells","authors":"Zhi-yong Yin , Qi-guang He , Xiao-wei Chen","doi":"10.1016/j.ijimpeng.2025.105587","DOIUrl":"10.1016/j.ijimpeng.2025.105587","url":null,"abstract":"<div><div>Fragmentation analysis in explosively driven cylindrical shells is crucial for weapon development and structural protection. To evaluate the overall response of protective structures to explosive fragments, it is essential to clarify the spatial distribution characteristics of the fragments. This study investigates the influence of fracture mode on fragment morphology and spatial distribution through numerical simulations, highlighting the non-uniform fragment distribution. A damage analysis method based on the kinetic energy of fragments is proposed, which illustrates both the spatial distribution and energy concentration in specific areas. The results reveal that the kinetic energy distribution of fragments exhibits a clustering effect only in shear fracture, corresponding to the elongated fragments generated from the middle of the cylindrical shell. Furthermore, a theoretical model is developed to determine the maximum kinetic energy angle, facilitating the rapid identification of severely damaged regions in protective structures. The experimental results validate the non-uniform distribution of perforation areas on witness plates and demonstrate that the theoretical model can accurately predict the location and extent of severe damage under varying conditions. This study provides an energy-based theoretical framework for damage assessment of explosive fragments, offering valuable insights for damage and protection design in fields such as the ship damage evaluation and the blast resistance of concrete structures.</div></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":"209 ","pages":"Article 105587"},"PeriodicalIF":5.1,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145579278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-10DOI: 10.1016/j.ijimpeng.2025.105585
Minghao Zhang , Zengqiang Cao , Shuaijia Kou , Yingjiang Guo , Yuanzhuo He , Yuejie Cao , Lubin Huo
The CFRP joining structures of aircraft fuselage not only withstand circumferential tensile loads, but also face the risk of external impacts. This study employed an impact approach based on electromagnetic force loading to conduct electromagnetic impact (EMI) tests at varying energy levels on CFRP/Al (aluminum alloy) four-rivet double-sided countersunk riveted joints in aircraft fuselage structures. The impact response and damage behavior were investigated. Subsequently, residual tensile strength and fatigue life tests were performed on these pre-impact riveted joints. During quasi-static tensile tests, acoustic emission (AE) technology was used to monitor the damage process of the structures, and six categories of damage were identified using the evidential c-means (ECM) algorithm. The research results indicate that an increase in the impact strain rate slightly raises the damage threshold load of CFRP laminates. The presence of rivets prevents further propagation of delamination, and the deformation of Al sheet can serve as an effective auxiliary means for detecting impact damage. For multi-riveted joints, the effects of impact behavior on the structure are localized, improving energy absorption without reducing the residual tensile strength. However, the CFRP damage and Al sheet deformation caused by the impact significantly reduce the fatigue life of the joints.
{"title":"Effect of pre-impact behavior based on electromagnetic force loading on the residual tensile strength and fatigue life of CFRP/Al multi-riveted structure","authors":"Minghao Zhang , Zengqiang Cao , Shuaijia Kou , Yingjiang Guo , Yuanzhuo He , Yuejie Cao , Lubin Huo","doi":"10.1016/j.ijimpeng.2025.105585","DOIUrl":"10.1016/j.ijimpeng.2025.105585","url":null,"abstract":"<div><div>The CFRP joining structures of aircraft fuselage not only withstand circumferential tensile loads, but also face the risk of external impacts. This study employed an impact approach based on electromagnetic force loading to conduct electromagnetic impact (EMI) tests at varying energy levels on CFRP/Al (aluminum alloy) four-rivet double-sided countersunk riveted joints in aircraft fuselage structures. The impact response and damage behavior were investigated. Subsequently, residual tensile strength and fatigue life tests were performed on these pre-impact riveted joints. During quasi-static tensile tests, acoustic emission (AE) technology was used to monitor the damage process of the structures, and six categories of damage were identified using the evidential c-means (ECM) algorithm. The research results indicate that an increase in the impact strain rate slightly raises the damage threshold load of CFRP laminates. The presence of rivets prevents further propagation of delamination, and the deformation of Al sheet can serve as an effective auxiliary means for detecting impact damage. For multi-riveted joints, the effects of impact behavior on the structure are localized, improving energy absorption without reducing the residual tensile strength. However, the CFRP damage and Al sheet deformation caused by the impact significantly reduce the fatigue life of the joints.</div></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":"209 ","pages":"Article 105585"},"PeriodicalIF":5.1,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145528630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-09DOI: 10.1016/j.ijimpeng.2025.105581
Júlio Jorge Braga de Carvalho Nunes , Pablo Augusto Krahl , Flávio de Andrade Silva
The demand for resilient materials in impact-prone structures has increased interest in UHPC reinforced with steel fibers. Known for its strength and energy absorption capacity, UHPC is a promising construction material that can be used under dynamic loading. However, a lack of tensile data at high strain rates (>100 s⁻¹) limits the development of predictive models and safe structural design. This study addresses this gap by investigating the strain-rate-sensitive tensile behavior of UHPC reinforced with smooth (SF) and hooked-end fibers (HF), using direct tension tests across a wide strain-rate range (quasi-static to ∼200 s⁻¹). Results demonstrate that, while matrix strength controls the first peak stress, fiber geometry governs post-cracking behavior, energy dissipation, and ductility. UHPC SF achieved up to 35 % higher second peak loads and 18–22 % greater dynamic toughness than UHPC HF, reaching 674 kJ/m³ at 195 s⁻¹. In contrast, UHPC HF reached higher maximum peak loads (up to 32 kN) and more stable first-peak responses, but suffered abrupt post-peak stress drops, with toughness values limited to ∼572 kJ/m³. At higher strain levels, UHPC SF benefited from its uniform fiber distribution and frictional pull-out, while UHPC HF relied on mechanical anchorage that was less effective beyond ∼100 s⁻¹. The Dynamic Increase Factor (DIF) for peak load ranged from 2.7 to 4.2 for UHPC HF and from 3.3 to 3.9 for UHPC SF, significantly exceeding by up to 40 % the typical DIF range (1.5–3.0) reported for conventional concretes. Ultimate strain reached up to 4.5 % at 195 s⁻¹, with UHPC SF exhibiting a more stable strain evolution, while UHPC HF showed sudden cracking and steeper load drops. This behavior highlights the crucial role of fiber bridging in absorbing high-velocity impacts. This comprehensive experimental campaign also supported the calibration of a numerical simulation by the Concrete Damage Plasticity (CDP) model with strain rate dependence, which reproduced the key post-peak features of both UHPCs and predicted peak loads with less than 8 % deviation across the entire strain-rate range, including interpolated intervals lacking direct experimental data. Numerical predictions aligned with experimental DIF trends, confirming the robustness of the model for dynamic tensile loading. In addition, the predictive model for DIF captured experimental behavior across all strain-rate ranges, confirming its applicability for UHPC under extreme dynamic loading. This integrative approach, combining mechanical characterization and numerical modeling, advances the understanding of mechanical behavior and damage evolution under dynamic tension, providing a foundation for more reliable design strategies in UHPC structures subjected to extreme loading scenarios.
{"title":"Tensile behavior of UHPC under high strain rates: Experimental and numerical analysis","authors":"Júlio Jorge Braga de Carvalho Nunes , Pablo Augusto Krahl , Flávio de Andrade Silva","doi":"10.1016/j.ijimpeng.2025.105581","DOIUrl":"10.1016/j.ijimpeng.2025.105581","url":null,"abstract":"<div><div>The demand for resilient materials in impact-prone structures has increased interest in UHPC reinforced with steel fibers. Known for its strength and energy absorption capacity, UHPC is a promising construction material that can be used under dynamic loading. However, a lack of tensile data at high strain rates (>100 s⁻¹) limits the development of predictive models and safe structural design. This study addresses this gap by investigating the strain-rate-sensitive tensile behavior of UHPC reinforced with smooth (SF) and hooked-end fibers (HF), using direct tension tests across a wide strain-rate range (quasi-static to ∼200 s⁻¹). Results demonstrate that, while matrix strength controls the first peak stress, fiber geometry governs post-cracking behavior, energy dissipation, and ductility. UHPC SF achieved up to 35 % higher second peak loads and 18–22 % greater dynamic toughness than UHPC HF, reaching 674 kJ/m³ at 195 s⁻¹. In contrast, UHPC HF reached higher maximum peak loads (up to 32 kN) and more stable first-peak responses, but suffered abrupt post-peak stress drops, with toughness values limited to ∼572 kJ/m³. At higher strain levels, UHPC SF benefited from its uniform fiber distribution and frictional pull-out, while UHPC HF relied on mechanical anchorage that was less effective beyond ∼100 s⁻¹. The Dynamic Increase Factor (DIF) for peak load ranged from 2.7 to 4.2 for UHPC HF and from 3.3 to 3.9 for UHPC SF, significantly exceeding by up to 40 % the typical DIF range (1.5–3.0) reported for conventional concretes. Ultimate strain reached up to 4.5 % at 195 s⁻¹, with UHPC SF exhibiting a more stable strain evolution, while UHPC HF showed sudden cracking and steeper load drops. This behavior highlights the crucial role of fiber bridging in absorbing high-velocity impacts. This comprehensive experimental campaign also supported the calibration of a numerical simulation by the Concrete Damage Plasticity (CDP) model with strain rate dependence, which reproduced the key post-peak features of both UHPCs and predicted peak loads with less than 8 % deviation across the entire strain-rate range, including interpolated intervals lacking direct experimental data. Numerical predictions aligned with experimental DIF trends, confirming the robustness of the model for dynamic tensile loading. In addition, the predictive model for DIF captured experimental behavior across all strain-rate ranges, confirming its applicability for UHPC under extreme dynamic loading. This integrative approach, combining mechanical characterization and numerical modeling, advances the understanding of mechanical behavior and damage evolution under dynamic tension, providing a foundation for more reliable design strategies in UHPC structures subjected to extreme loading scenarios.</div></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":"209 ","pages":"Article 105581"},"PeriodicalIF":5.1,"publicationDate":"2025-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145529216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-08DOI: 10.1016/j.ijimpeng.2025.105584
Guocong Liang , Huawei Li , Wensu Chen , Hong Hao
Reinforced concrete (RC) beams are susceptible to negative bending moment (NBM) damage near supports under impact loads from various sources such as falling debris. This damage mode, caused by upward inertia forces, can severely compromise structural integrity, yet its quantitative prediction remains challenging due to the complex dynamic interactions. To date, the impact force profile characteristics (e.g., peak force and duration) and structural parameters (e.g., beam span and reinforcement ratio) that influence the dynamic response of RC beams have been extensively investigated. However, the relationship between the frequency contents of impact forces that excite higher-order response modes and the severity of NBM damage has received limited attention. In this study, the initiation and development mechanisms of NBM damage of RC beams are investigated. Using validated numerical models and Fast Fourier Transform analysis, it is found that the high-frequency components of the primary impact pulse that sufficiently excite the high vibration modes govern NBM damage severity. The larger spectral amplitude of impact force at corresponding frequencies of high vibration modes of beams induces more severe NBM damage. Larger impact force with shorter impulse duration results in a wider impact force frequency band, which in turn enhances the excitation of high-order modes and intensifies the NBM damage severity. A damage assessment method is developed based on spectral amplitudes of impact force at beam modal frequencies to quantitatively assess the severity of NBM damage in RC beams. The proposed framework provides a practical and effective tool for impact damage assessment of RC beams.
{"title":"Impact force frequency characteristics and their influence on damage modes of reinforced concrete beams","authors":"Guocong Liang , Huawei Li , Wensu Chen , Hong Hao","doi":"10.1016/j.ijimpeng.2025.105584","DOIUrl":"10.1016/j.ijimpeng.2025.105584","url":null,"abstract":"<div><div>Reinforced concrete (RC) beams are susceptible to negative bending moment (NBM) damage near supports under impact loads from various sources such as falling debris. This damage mode, caused by upward inertia forces, can severely compromise structural integrity, yet its quantitative prediction remains challenging due to the complex dynamic interactions. To date, the impact force profile characteristics (e.g., peak force and duration) and structural parameters (e.g., beam span and reinforcement ratio) that influence the dynamic response of RC beams have been extensively investigated. However, the relationship between the frequency contents of impact forces that excite higher-order response modes and the severity of NBM damage has received limited attention. In this study, the initiation and development mechanisms of NBM damage of RC beams are investigated. Using validated numerical models and Fast Fourier Transform analysis, it is found that the high-frequency components of the primary impact pulse that sufficiently excite the high vibration modes govern NBM damage severity. The larger spectral amplitude of impact force at corresponding frequencies of high vibration modes of beams induces more severe NBM damage. Larger impact force with shorter impulse duration results in a wider impact force frequency band, which in turn enhances the excitation of high-order modes and intensifies the NBM damage severity. A damage assessment method is developed based on spectral amplitudes of impact force at beam modal frequencies to quantitatively assess the severity of NBM damage in RC beams. The proposed framework provides a practical and effective tool for impact damage assessment of RC beams.</div></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":"209 ","pages":"Article 105584"},"PeriodicalIF":5.1,"publicationDate":"2025-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145528629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-06DOI: 10.1016/j.ijimpeng.2025.105580
Hu Zhou , Ange Lu , Cheng Zheng , Xiangshao Kong , Weiguo Wu
Cased charges are usually simplified as equivalent bare charges to characterize the energy dissipation and conversion caused by fragmentation and initial kinetic energy of metal casing under the driven force from inner detonation pressure. However, this conventional simplification method inherently neglects the afterburning effects of detonation products, introducing significant risks when applying cased charge analytical models to confined explosions. In this paper, three different configurations of cased charge were employed to investigate the energy release characteristic in confined explosion scenarios experimentally and numerically. In addition, comparative analyses were performed between bare charges and cased charges. The test results reveal that the initial peak overpressure of cased charge was significantly lower than that of the bare charge, but the quasi-static pressures were very close to each other, maintaining differences within 6 %. Numerical simulations employing the Smooth Particle Hydrodynamics (SPH) method were conducted to quantify the energy dissipation caused by casing fragmentation. Based on detonation energy conservation principles, equivalent bare charges with mass reductions of approximately 30 % compared to the initial cased charges were derived. However, pressure load analysis demonstrates substantial discrepancies exceeding 50 % in quasi-static pressure predictions between equivalent bare charges and cased charge configurations. To address this limitation, a reactive flow-based model was developed, explicitly incorporating chemical reactions and casing-product interactions. The proposed model achieved excellent agreement with experimental pressure histories in both temporal evolution and magnitude. Furthermore, a two-phase pressure load simplification framework was established based on pressure distribution and evolution patterns, which successfully reconciled with dynamic responses of target plate recorded in experiments. Furthermore, the critical role of quasi-static pressure in governing structural dynamic responses within confined spaces was identified through numerical analysis.
{"title":"Study on blast loading from cased charges in confined spaces using reactive flow modelling of afterburning","authors":"Hu Zhou , Ange Lu , Cheng Zheng , Xiangshao Kong , Weiguo Wu","doi":"10.1016/j.ijimpeng.2025.105580","DOIUrl":"10.1016/j.ijimpeng.2025.105580","url":null,"abstract":"<div><div>Cased charges are usually simplified as equivalent bare charges to characterize the energy dissipation and conversion caused by fragmentation and initial kinetic energy of metal casing under the driven force from inner detonation pressure. However, this conventional simplification method inherently neglects the afterburning effects of detonation products, introducing significant risks when applying cased charge analytical models to confined explosions. In this paper, three different configurations of cased charge were employed to investigate the energy release characteristic in confined explosion scenarios experimentally and numerically. In addition, comparative analyses were performed between bare charges and cased charges. The test results reveal that the initial peak overpressure of cased charge was significantly lower than that of the bare charge, but the quasi-static pressures were very close to each other, maintaining differences within 6 %. Numerical simulations employing the Smooth Particle Hydrodynamics (SPH) method were conducted to quantify the energy dissipation caused by casing fragmentation. Based on detonation energy conservation principles, equivalent bare charges with mass reductions of approximately 30 % compared to the initial cased charges were derived. However, pressure load analysis demonstrates substantial discrepancies exceeding 50 % in quasi-static pressure predictions between equivalent bare charges and cased charge configurations. To address this limitation, a reactive flow-based model was developed, explicitly incorporating chemical reactions and casing-product interactions. The proposed model achieved excellent agreement with experimental pressure histories in both temporal evolution and magnitude. Furthermore, a two-phase pressure load simplification framework was established based on pressure distribution and evolution patterns, which successfully reconciled with dynamic responses of target plate recorded in experiments. Furthermore, the critical role of quasi-static pressure in governing structural dynamic responses within confined spaces was identified through numerical analysis.</div></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":"209 ","pages":"Article 105580"},"PeriodicalIF":5.1,"publicationDate":"2025-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145528632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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