Accurate measurement of initial fragment velocities is critical for characterizing dispersion and shocked fragment interactions inside the explosion cloud. Conventional techniques yield only time-averaged data, missing early-stage dynamics inside harsh explosive environments. This study employs Digital Inline Holography (DIH) with sub-µs exposure to track early-stage dynamics of preformed fragments in single- and three-fragment configurations using two electric detonators, Det-1 and Det-2, with different explosive masses. Despite its higher explosive mass, Det-1 produced lower fragment velocities than Det-2 due to higher energy absorption through deformation and fracture. In the three-fragment inline setup, the outermost fragment consistently attained the highest velocity, driven by shock transmission. The fragments showed significant deceleration due to increased density inside the cloud in both detonator configurations. Energy absorbed in fragment deformation was analyzed using SEM and XRD. Results showed that fragments from Det-1 absorbed more energy, resulting in lower initial velocities. A velocity decay model, incorporating effective density and drag, supported experimental trends. Overall, this study provides continuous time-resolved fragment velocity characterization in harsh explosive environments, offering critical insights into shock–fragment interactions, energy partitioning, and preformed fragmentation behaviour.
{"title":"Capturing early fragment dynamics in dense explosion clouds","authors":"Arpit Joglekar , Vishal Jagadale , Devashish Chorey , Viwek Mahto , Paras Nath Verma , Kusumkant Dhote , Devendra Deshmukh","doi":"10.1016/j.ijimpeng.2026.105660","DOIUrl":"10.1016/j.ijimpeng.2026.105660","url":null,"abstract":"<div><div>Accurate measurement of initial fragment velocities is critical for characterizing dispersion and shocked fragment interactions inside the explosion cloud. Conventional techniques yield only time-averaged data, missing early-stage dynamics inside harsh explosive environments. This study employs Digital Inline Holography (DIH) with sub-µs exposure to track early-stage dynamics of preformed fragments in single- and three-fragment configurations using two electric detonators, Det-1 and Det-2, with different explosive masses. Despite its higher explosive mass, Det-1 produced lower fragment velocities than Det-2 due to higher energy absorption through deformation and fracture. In the three-fragment inline setup, the outermost fragment consistently attained the highest velocity, driven by shock transmission. The fragments showed significant deceleration due to increased density inside the cloud in both detonator configurations. Energy absorbed in fragment deformation was analyzed using SEM and XRD. Results showed that fragments from Det-1 absorbed more energy, resulting in lower initial velocities. A velocity decay model, incorporating effective density and drag, supported experimental trends. Overall, this study provides continuous time-resolved fragment velocity characterization in harsh explosive environments, offering critical insights into shock–fragment interactions, energy partitioning, and preformed fragmentation behaviour.</div></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":"212 ","pages":"Article 105660"},"PeriodicalIF":5.1,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038607","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 : 2026-01-19DOI: 10.1016/j.ijimpeng.2026.105659
Wenhao Ren, Siha A
Wind and sand erosion is a key environmental factor affecting the service life of fiber-reinforced composite materials, but the mechanical degradation mechanisms of different types of composite structures under multi-parameter erosion remain unclear. This study utilized a jet erosion test platform to systematically evaluate the performance evolution of three typical structures—GFRP, BFRP, and CFRP—under varying erosion angles (15°–90°), velocities (16–31 m/s), and durations (10–50 min). The results show that all three undergo damage processes such as resin delamination, fiber exposure, and interlaminar debonding, with 60° being the most prone angle for failure. CFRP exhibits the highest strength retention rate (82%), but the most significant modulus decrease (14.9%); GFRP experiences over a 30% strength reduction under prolonged erosion, while BFRP exhibits strain separation and early instability. Stress-strain and multi-point strain analyses indicate that CFRP maintains deformation consistency after erosion; GFRP exhibits more ductile behavior accompanied by progressive strain bifurcation; while BFRP demonstrates moderate mechanical response with limited strain compatibility. The semi-empirical predictive model constructed further achieved good fitting on all three materials (R² > 0.84), validating its cross-material applicability. The research results provide a theoretical basis for corrosion-resistant design, surface protection, and life prediction of composite structures under complex operating conditions.
{"title":"Comparative study on sand erosion damage and residual strength of GFRP, BFRP, and CFRP composites","authors":"Wenhao Ren, Siha A","doi":"10.1016/j.ijimpeng.2026.105659","DOIUrl":"10.1016/j.ijimpeng.2026.105659","url":null,"abstract":"<div><div>Wind and sand erosion is a key environmental factor affecting the service life of fiber-reinforced composite materials, but the mechanical degradation mechanisms of different types of composite structures under multi-parameter erosion remain unclear. This study utilized a jet erosion test platform to systematically evaluate the performance evolution of three typical structures—GFRP, BFRP, and CFRP—under varying erosion angles (15°–90°), velocities (16–31 m/s), and durations (10–50 min). The results show that all three undergo damage processes such as resin delamination, fiber exposure, and interlaminar debonding, with 60° being the most prone angle for failure. CFRP exhibits the highest strength retention rate (82%), but the most significant modulus decrease (14.9%); GFRP experiences over a 30% strength reduction under prolonged erosion, while BFRP exhibits strain separation and early instability. Stress-strain and multi-point strain analyses indicate that CFRP maintains deformation consistency after erosion; GFRP exhibits more ductile behavior accompanied by progressive strain bifurcation; while BFRP demonstrates moderate mechanical response with limited strain compatibility. The semi-empirical predictive model constructed further achieved good fitting on all three materials (R² > 0.84), validating its cross-material applicability. The research results provide a theoretical basis for corrosion-resistant design, surface protection, and life prediction of composite structures under complex operating conditions.</div></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":"212 ","pages":"Article 105659"},"PeriodicalIF":5.1,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038490","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}
To address the fact that existing studies on rigid-projectile penetration are largely concentrated on aluminum alloys and low-strength steels, while providing insufficient descriptions of the penetration process and target-side energy partitioning for medium-to-high-strength armor steels under semi-infinite conditions, this work investigates the normal-impact penetration of a 12.7 mm armor-piercing incendiary (API) projectile core into semi-infinite low-strength 45 steel and high-strength 603 steel targets. Ballistic experiments, theoretical modeling, and explicit numerical simulations are combined to systematically study the evolution of penetration resistance acting on the projectile core and the associated energy-dissipation mechanisms. The experimental results show that the crater profile closely conforms to the projectile-core morphology, providing direct experimental evidence that the core can still maintain a rigid-penetration regime in the high-strength 603 steel. At the nose-surface level, the present model explicitly decomposes the contact pressure into a quasi-static strength-controlled term and a dynamic inertial term governed by the interfacial normal velocity, thereby yielding equivalent resistance and penetration-depth expressions for ogive-nosed projectiles without introducing additional empirical parameters. Compared with numerical simulations and other models, the proposed framework can reproduce the characteristic three-stage evolution of the resistance history. Furthermore, an energy bookkeeping and conservation-closure procedure is established around four channels, namely normal/tangential and quasi-static/dynamic contributions. Finally, a non-dimensional penetration-depth prediction for semi-infinite steel is derived, together with its applicability bounds over the caliber-radius-head (CRH), friction coefficient, and velocity ranges, providing a reusable physics-based tool for rapid assessment and model calibration of rigid-projectile penetration into high-strength steel armor.
{"title":"Penetration behavior and energy-partition mechanisms of a 12.7 mm armor-piercing incendiary projectile into semi-infinite steel targets","authors":"Yiding Wu, Wencheng Lu, Xinyu Sun, Shuangqi Li, Bingzhuo Hu, Guangfa Gao","doi":"10.1016/j.ijimpeng.2026.105662","DOIUrl":"10.1016/j.ijimpeng.2026.105662","url":null,"abstract":"<div><div>To address the fact that existing studies on rigid-projectile penetration are largely concentrated on aluminum alloys and low-strength steels, while providing insufficient descriptions of the penetration process and target-side energy partitioning for medium-to-high-strength armor steels under semi-infinite conditions, this work investigates the normal-impact penetration of a 12.7 mm armor-piercing incendiary (API) projectile core into semi-infinite low-strength 45 steel and high-strength 603 steel targets. Ballistic experiments, theoretical modeling, and explicit numerical simulations are combined to systematically study the evolution of penetration resistance acting on the projectile core and the associated energy-dissipation mechanisms. The experimental results show that the crater profile closely conforms to the projectile-core morphology, providing direct experimental evidence that the core can still maintain a rigid-penetration regime in the high-strength 603 steel. At the nose-surface level, the present model explicitly decomposes the contact pressure into a quasi-static strength-controlled term and a dynamic inertial term governed by the interfacial normal velocity, thereby yielding equivalent resistance and penetration-depth expressions for ogive-nosed projectiles without introducing additional empirical parameters. Compared with numerical simulations and other models, the proposed framework can reproduce the characteristic three-stage evolution of the resistance history. Furthermore, an energy bookkeeping and conservation-closure procedure is established around four channels, namely normal/tangential and quasi-static/dynamic contributions. Finally, a non-dimensional penetration-depth prediction for semi-infinite steel is derived, together with its applicability bounds over the caliber-radius-head (CRH), friction coefficient, and velocity ranges, providing a reusable physics-based tool for rapid assessment and model calibration of rigid-projectile penetration into high-strength steel armor.</div></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":"212 ","pages":"Article 105662"},"PeriodicalIF":5.1,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078339","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 : 2026-01-19DOI: 10.1016/j.ijimpeng.2026.105661
Xiaolong Chen , Li Chen , Huu-Tai Thai , Qin Fang
Existing models have not consistently captured the scaling effects associated with deformable penetration of flat-nosed long rods into concrete. This paper proposes a novel semi-analytical model that explicitly incorporates the projectile diameter-to-aggregate size ratio. The projectile is treated as a control volume. Based on conservation laws and wave impedance conditions, an analytical model for the residual diameter is derived. A scaling-informed penetration resistance is used to define a yield velocity that accounts for the projectile diameter-to-aggregate size ratio. This velocity is then incorporated into a Forrestal-type resistance model, resulting in a closed-form solution for penetration depth. The model was validated against experimental data and numerical simulations. It captures the transition to the deformable regime and the subsequent reduction in penetration depth due to nose bulging. The model also captures two key scaling laws: (1) the normalized residual diameter decreases as the projectile diameter increases, and (2) the normalized penetration depth increases monotonically. Overall, the proposed model provides a unified framework that links scaling effects with deformable penetration behavior, and can be used as a useful tool for practical protective design.
{"title":"A semi-analytical model incorporating scaling effects for deformable penetration of flat-nosed long rods into semi-infinite concrete targets","authors":"Xiaolong Chen , Li Chen , Huu-Tai Thai , Qin Fang","doi":"10.1016/j.ijimpeng.2026.105661","DOIUrl":"10.1016/j.ijimpeng.2026.105661","url":null,"abstract":"<div><div>Existing models have not consistently captured the scaling effects associated with deformable penetration of flat-nosed long rods into concrete. This paper proposes a novel semi-analytical model that explicitly incorporates the projectile diameter-to-aggregate size ratio. The projectile is treated as a control volume. Based on conservation laws and wave impedance conditions, an analytical model for the residual diameter is derived. A scaling-informed penetration resistance is used to define a yield velocity that accounts for the projectile diameter-to-aggregate size ratio. This velocity is then incorporated into a Forrestal-type resistance model, resulting in a closed-form solution for penetration depth. The model was validated against experimental data and numerical simulations. It captures the transition to the deformable regime and the subsequent reduction in penetration depth due to nose bulging. The model also captures two key scaling laws: (1) the normalized residual diameter decreases as the projectile diameter increases, and (2) the normalized penetration depth increases monotonically. Overall, the proposed model provides a unified framework that links scaling effects with deformable penetration behavior, and can be used as a useful tool for practical protective design.</div></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":"212 ","pages":"Article 105661"},"PeriodicalIF":5.1,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038487","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 : 2026-01-19DOI: 10.1016/j.ijimpeng.2026.105655
Gan Li , Xiaochen Li , Yuguo Ji , Chao Li , Chunming Song , Jie Li , Mingyang Wang
As the penetration velocity increases, the scale effect observed in scaled experiments on concrete and rock-like brittle media becomes increasingly pronounced, necessitating a re-examination and revision of the corresponding penetration similarity laws. This paper presents a quantitative investigation of the scale effect associated with long-rod projectiles penetrating geological brittle materials, such as rock and concrete. Based on a dynamic strength model for brittle materials that incorporates the effects of hydrostatic pressure and strain-rate strengthening, we establish a penetration resistance model, a penetration depth prediction model, and a method for determining the model parameters. This framework enables a quantitative description of the "scale effect" in rigid projectile penetration, achieving a prediction error of less than 15% across the entire range of projectile sizes considered. The results demonstrate that, during the rigid penetration phase, both penetration resistance and penetration depth exhibit significant scale effects. The penetration resistance is primarily composed of a strength term and a hydrostatic pressure term, with the strain-rate enhancement of the strength term being the principal cause of the scale effect. At a constant impact velocity, the relationship between the scale effect on penetration depth and the geometric scaling factor λ can be accurately described by a power-law function, where the exponent characterizes the magnitude of the scale effect. Within the range of impact velocities investigated herein, this scale-effect exponent varies from 0.275 to 0.042. Furthermore, the influences of target parameters—including material strength, bulk modulus, and strain-rate sensitivity—as well as projectile parameters—such as density, length-to-diameter ratio, and nose shape coefficient—on the penetration scale effect are systematically analyzed. The findings of this study can be employed to interpret the results of scaled penetration tests and to guide practical ammunition engineering design.
{"title":"Scaling effect of long-rod projectiles penetrating into geological material targets","authors":"Gan Li , Xiaochen Li , Yuguo Ji , Chao Li , Chunming Song , Jie Li , Mingyang Wang","doi":"10.1016/j.ijimpeng.2026.105655","DOIUrl":"10.1016/j.ijimpeng.2026.105655","url":null,"abstract":"<div><div>As the penetration velocity increases, the scale effect observed in scaled experiments on concrete and rock-like brittle media becomes increasingly pronounced, necessitating a re-examination and revision of the corresponding penetration similarity laws. This paper presents a quantitative investigation of the scale effect associated with long-rod projectiles penetrating geological brittle materials, such as rock and concrete. Based on a dynamic strength model for brittle materials that incorporates the effects of hydrostatic pressure and strain-rate strengthening, we establish a penetration resistance model, a penetration depth prediction model, and a method for determining the model parameters. This framework enables a quantitative description of the \"scale effect\" in rigid projectile penetration, achieving a prediction error of less than 15% across the entire range of projectile sizes considered. The results demonstrate that, during the rigid penetration phase, both penetration resistance and penetration depth exhibit significant scale effects. The penetration resistance is primarily composed of a strength term and a hydrostatic pressure term, with the strain-rate enhancement of the strength term being the principal cause of the scale effect. At a constant impact velocity, the relationship between the scale effect on penetration depth and the geometric scaling factor λ can be accurately described by a power-law function, where the exponent characterizes the magnitude of the scale effect. Within the range of impact velocities investigated herein, this scale-effect exponent varies from 0.275 to 0.042. Furthermore, the influences of target parameters—including material strength, bulk modulus, and strain-rate sensitivity—as well as projectile parameters—such as density, length-to-diameter ratio, and nose shape coefficient—on the penetration scale effect are systematically analyzed. The findings of this study can be employed to interpret the results of scaled penetration tests and to guide practical ammunition engineering design.</div></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":"212 ","pages":"Article 105655"},"PeriodicalIF":5.1,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038486","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 : 2026-01-19DOI: 10.1016/j.ijimpeng.2026.105656
D. Karagiozova , T.X. Yu
The dynamics of oblique impact and rebound of thin-walled spheres, such as ping pong balls, present a rich and complex interplay of solid mechanics, materials science, and impact dynamics. Through a combination of experimental verifications, analyses and numerical simulations, this paper intends to integrate the elastic-plastic property of material, snap-through buckling of spherical shell, frictional contact mechanics, and initial spin effects to provide a comprehensive framework for understanding the impact dynamics of ping pong balls. It is demonstrated that the dynamic response of the ping pong ball after oblique collision may contain sliding along the target surface and/or may be gripped by surface’s friction, depending on a combination of the impact velocity, the incident angle, the initial spin of the ball and friction of the surface. These input parameters also significantly affect the energy partitioning during the dynamic response and dictate the rebound properties, such as coefficient of restitution (CoR) and rebound angle. The critical condition related to the impact velocity and the incident angle, under which a local snap-through buckling will occur is numerically investigated, and the influences of the snap-through buckling on the energy dissipation and rebounding properties are revealed. It is shown that the initial spin direction strongly influences the snap-through bucking initiation and the instance of ball gripping.
{"title":"Oblique impact and rebound of a ping pong ball with spin on a frictional surface","authors":"D. Karagiozova , T.X. Yu","doi":"10.1016/j.ijimpeng.2026.105656","DOIUrl":"10.1016/j.ijimpeng.2026.105656","url":null,"abstract":"<div><div>The dynamics of oblique impact and rebound of thin-walled spheres, such as ping pong balls, present a rich and complex interplay of solid mechanics, materials science, and impact dynamics. Through a combination of experimental verifications, analyses and numerical simulations, this paper intends to integrate the elastic-plastic property of material, snap-through buckling of spherical shell, frictional contact mechanics, and initial spin effects to provide a comprehensive framework for understanding the impact dynamics of ping pong balls. It is demonstrated that the dynamic response of the ping pong ball after oblique collision may contain sliding along the target surface and/or may be gripped by surface’s friction, depending on a combination of the impact velocity, the incident angle, the initial spin of the ball and friction of the surface. These input parameters also significantly affect the energy partitioning during the dynamic response and dictate the rebound properties, such as coefficient of restitution (CoR) and rebound angle. The critical condition related to the impact velocity and the incident angle, under which a local snap-through buckling will occur is numerically investigated, and the influences of the snap-through buckling on the energy dissipation and rebounding properties are revealed. It is shown that the initial spin direction strongly influences the snap-through bucking initiation and the instance of ball gripping.</div></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":"212 ","pages":"Article 105656"},"PeriodicalIF":5.1,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038491","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}
Understanding the dynamic response of ice is essential for modeling ice‑related engineering problems. In this study, the dynamic compressive behavior of columnar freshwater ice at temperatures from -10 to -50°C and strain rates of 6 to 250 s-1 is obtained using a cryogenic split Hopkinson pressure bar. The effects of crystal orientation, strain rate, and temperature on the mechanical response of the ice are investigated. The results show that the strengths of ice at 0° and 90° crystal orientation increase with increasing strain rate and decreasing temperature. In addition, the columnar ice exhibits pronounced anisotropy. The peak strength at 0° orientation is significantly higher than at 90° orientation, with a near-constant strength ratio of 1.45. The failure mode of the ice is also orientation‑controlled, with axial splitting at 0°orientation and oblique shear banding at 90° orientation. A unified strength scaling law is developed, incorporating ice texture, strain rate, and temperature, and it successfully captures dynamic strength data from both the literature and the present study. This work advances the understanding of the dynamic behavior of ice and provides a unified constitutive model for analyzing ice-structure interactions.
{"title":"Dynamic compression behavior of columnar freshwater ice at intermediate strain rates","authors":"Y.D. Sui , Z.P. Gu , J.P. Ren , J.Z. Yue , C.G. Huang , X.Q. Wu","doi":"10.1016/j.ijimpeng.2026.105654","DOIUrl":"10.1016/j.ijimpeng.2026.105654","url":null,"abstract":"<div><div>Understanding the dynamic response of ice is essential for modeling ice‑related engineering problems. In this study, the dynamic compressive behavior of columnar freshwater ice at temperatures from -10 to -50°C and strain rates of 6 to 250 s<sup>-1</sup> is obtained using a cryogenic split Hopkinson pressure bar. The effects of crystal orientation, strain rate, and temperature on the mechanical response of the ice are investigated. The results show that the strengths of ice at 0° and 90° crystal orientation increase with increasing strain rate and decreasing temperature. In addition, the columnar ice exhibits pronounced anisotropy. The peak strength at 0° orientation is significantly higher than at 90° orientation, with a near-constant strength ratio of 1.45. The failure mode of the ice is also orientation‑controlled, with axial splitting at 0°orientation and oblique shear banding at 90° orientation. A unified strength scaling law is developed, incorporating ice texture, strain rate, and temperature, and it successfully captures dynamic strength data from both the literature and the present study. This work advances the understanding of the dynamic behavior of ice and provides a unified constitutive model for analyzing ice-structure interactions.</div></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":"212 ","pages":"Article 105654"},"PeriodicalIF":5.1,"publicationDate":"2026-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078455","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}
Repeated impact events are frequently encountered in engineering structures, where the cumulative effects may influence structural precision, vibration control, and long-term stability. In repeated impact problems, the dynamic complexity introduced by multiple sub-impacts has not yet been sufficiently addressed. To gain insight into the mechanism of repeated impacts, this study investigates the multiple sub-impact phenomenon and its influences on the repeated impact responses using a finite element method. A nonlinear finite element model is developed to investigate the repeated impact problem on slender elastic-viscoplastic beams. The model incorporates the effects of strain rate dependence, residual deformation, and stress wave propagation, and it is validated against experimental results with good agreement. Numerical results reveal that multiple sub-impacts, caused by insufficient sphere rebound and strong beam vibration, are ubiquitous in every repeated impact. Compared with single-impact predictions, multiple sub-impacts alter repeated impact dynamics significantly by introducing additional excitation into the impact system. The occurrence of multiple sub-impacts leads to random variations in force and displacement histories, alters energy dissipation patterns, and increases the impact numbers required for achieving pseudo-shakedown state. Moreover, the characteristics of sub-impacts are strongly dependent on impact location, leading to distinct repeated impact responses at different locations. Therefore, this study demonstrates that multiple sub-impacts significantly influence the repeated impact responses, and these findings highlight the importance of accounting for the multiple sub-impact effects in the design, optimization and analysis of engineering structures under repeated impacts.
{"title":"Influences of multiple sub-impacts on the repeated impact responses of flexible beams","authors":"Liang Jiang , Yuanyuan Guo , Xiaochun Yin , Panpan Weng , Huaiping Ding , Cheng Gao","doi":"10.1016/j.ijimpeng.2026.105653","DOIUrl":"10.1016/j.ijimpeng.2026.105653","url":null,"abstract":"<div><div>Repeated impact events are frequently encountered in engineering structures, where the cumulative effects may influence structural precision, vibration control, and long-term stability. In repeated impact problems, the dynamic complexity introduced by multiple sub-impacts has not yet been sufficiently addressed. To gain insight into the mechanism of repeated impacts, this study investigates the multiple sub-impact phenomenon and its influences on the repeated impact responses using a finite element method. A nonlinear finite element model is developed to investigate the repeated impact problem on slender elastic-viscoplastic beams. The model incorporates the effects of strain rate dependence, residual deformation, and stress wave propagation, and it is validated against experimental results with good agreement. Numerical results reveal that multiple sub-impacts, caused by insufficient sphere rebound and strong beam vibration, are ubiquitous in every repeated impact. Compared with single-impact predictions, multiple sub-impacts alter repeated impact dynamics significantly by introducing additional excitation into the impact system. The occurrence of multiple sub-impacts leads to random variations in force and displacement histories, alters energy dissipation patterns, and increases the impact numbers required for achieving pseudo-shakedown state. Moreover, the characteristics of sub-impacts are strongly dependent on impact location, leading to distinct repeated impact responses at different locations. Therefore, this study demonstrates that multiple sub-impacts significantly influence the repeated impact responses, and these findings highlight the importance of accounting for the multiple sub-impact effects in the design, optimization and analysis of engineering structures under repeated impacts.</div></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":"212 ","pages":"Article 105653"},"PeriodicalIF":5.1,"publicationDate":"2026-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078458","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 : 2026-01-14DOI: 10.1016/j.ijimpeng.2026.105652
Chenyu Gao , Junbo Yan , Yan Liu , Wei Lu , Ning Huang , Fan Bai , Fenglei Huang
Deeply buried and ultrahigh-strength protective structures often require multiple sequential penetration-explosion cycles to be effectively neutralized. This study focuses on the secondary penetration behavior of ultrahigh-performance concrete (UHPC) targets after an initial penetration and explosion sequence, a subject that has received limited systematic attention. First, a series of penetration-explosion-penetration tests was performed on UHPC targets, with systematically varying secondary impact locations to examine their effect on penetration depth and local failure characteristics. Experimental results reveal that secondary penetration performance varied significantly with impact position, showing distinct differences in both the increase in penetration depth and the degree of projectile redirection across tested locations. In addition, a computational model incorporating the restart method was developed and rigorously validated through comparisons with experimental data. Furthermore, a systematic parametric study was conducted to examine the influence of impact location, velocity, and accumulated material damage on secondary penetration behavior, accompanied by a discussion of the underlying physical mechanisms.
{"title":"Secondary penetration behavior in UHPC targets after penetration-explosion events","authors":"Chenyu Gao , Junbo Yan , Yan Liu , Wei Lu , Ning Huang , Fan Bai , Fenglei Huang","doi":"10.1016/j.ijimpeng.2026.105652","DOIUrl":"10.1016/j.ijimpeng.2026.105652","url":null,"abstract":"<div><div>Deeply buried and ultrahigh-strength protective structures often require multiple sequential penetration-explosion cycles to be effectively neutralized. This study focuses on the secondary penetration behavior of ultrahigh-performance concrete (UHPC) targets after an initial penetration and explosion sequence, a subject that has received limited systematic attention. First, a series of penetration-explosion-penetration tests was performed on UHPC targets, with systematically varying secondary impact locations to examine their effect on penetration depth and local failure characteristics. Experimental results reveal that secondary penetration performance varied significantly with impact position, showing distinct differences in both the increase in penetration depth and the degree of projectile redirection across tested locations. In addition, a computational model incorporating the restart method was developed and rigorously validated through comparisons with experimental data. Furthermore, a systematic parametric study was conducted to examine the influence of impact location, velocity, and accumulated material damage on secondary penetration behavior, accompanied by a discussion of the underlying physical mechanisms.</div></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":"212 ","pages":"Article 105652"},"PeriodicalIF":5.1,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038485","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}
Graded cellular projectiles (GCPs) have emerged as promising blast-loading simulators due to their controllable impact loads, offering potential for rapid evaluation of anti-blast performance of structures. The coupling relations between velocity and pressure at the projectile–plate interface play a critical role in determining the impact loads. However, for prevalent plate structures, the coupling process between projectiles and plates remains unclear, which limits the density design of GCPs and their application in testing the blast resistance of plates. In this work, the dynamic response process of linear GCPs impacting clamped circular plates is studied through theoretical, numerical, and experimental methods. A projectile–plate coupling (PPC) analysis theory is established by integrating the shock wave model of projectiles, the moving plastic hinge model of plates, and the velocity consistency condition at the projectile–plate interface. A membrane factor method (MFM) is employed to simplify the governing equations of plates under large deflection without compromising the prediction accuracy. Theoretical predictions demonstrate that, under equivalent momentum and kinetic energy, cellular projectiles with negative density gradients or high matrix material strength exhibit higher kinetic energy transfer efficiency and induce greater permanent deformation of plates compared to the projectiles with uniform/positive density gradients or low matrix material strength. Dimensionless analysis indicates that the areal mass ratio of the projectile to the plate is the dominant parameter governing the projectile–plate coupling effect. Increasing the areal mass ratio enhances the coupling effect and amplifies the influence of density gradients on the impact process. Finite element simulations utilizing the 3D Voronoi technique, combined with experimental impact tests on 3D-printed GCPs, demonstrate the predictive accuracy of the theory with high reliability. The proposed theory elucidates the coupling mechanism between projectiles and deformable plates, which lays a solid foundation for the density design of GCPs applied in anti-blast evaluation.
{"title":"Impact dynamics of graded cellular projectiles on clamped circular plates: A coupling analysis theory and verification","authors":"Yuanrui Zhang , Yudong Zhu , Chenglin Gou , Hang Zheng , Qi Zhou , Kehong Wang , T.X. Yu , Jilin Yu , Zhijun Zheng","doi":"10.1016/j.ijimpeng.2026.105641","DOIUrl":"10.1016/j.ijimpeng.2026.105641","url":null,"abstract":"<div><div>Graded cellular projectiles (GCPs) have emerged as promising blast-loading simulators due to their controllable impact loads, offering potential for rapid evaluation of anti-blast performance of structures. The coupling relations between velocity and pressure at the projectile–plate interface play a critical role in determining the impact loads. However, for prevalent plate structures, the coupling process between projectiles and plates remains unclear, which limits the density design of GCPs and their application in testing the blast resistance of plates. In this work, the dynamic response process of linear GCPs impacting clamped circular plates is studied through theoretical, numerical, and experimental methods. A projectile–plate coupling (PPC) analysis theory is established by integrating the shock wave model of projectiles, the moving plastic hinge model of plates, and the velocity consistency condition at the projectile–plate interface. A membrane factor method (MFM) is employed to simplify the governing equations of plates under large deflection without compromising the prediction accuracy. Theoretical predictions demonstrate that, under equivalent momentum and kinetic energy, cellular projectiles with negative density gradients or high matrix material strength exhibit higher kinetic energy transfer efficiency and induce greater permanent deformation of plates compared to the projectiles with uniform/positive density gradients or low matrix material strength. Dimensionless analysis indicates that the areal mass ratio of the projectile to the plate is the dominant parameter governing the projectile–plate coupling effect. Increasing the areal mass ratio enhances the coupling effect and amplifies the influence of density gradients on the impact process. Finite element simulations utilizing the 3D Voronoi technique, combined with experimental impact tests on 3D-printed GCPs, demonstrate the predictive accuracy of the theory with high reliability. The proposed theory elucidates the coupling mechanism between projectiles and deformable plates, which lays a solid foundation for the density design of GCPs applied in anti-blast evaluation.</div></div>","PeriodicalId":50318,"journal":{"name":"International Journal of Impact Engineering","volume":"212 ","pages":"Article 105641"},"PeriodicalIF":5.1,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038489","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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