The quality-factor of hemispherical resonators is one of the important factors affecting the precision and performance of hemispherical resonator gyroscopes (HRGs). This study investigates the generation mechanism of subsurface damage (SSD) cracks in hemispherical resonators and their impact on the quality-factor, proposing a chemical etching method to enhance the quality-factor. First, a grinding model of a rotating grinding wheel was established based on indentation fracture theory, which reveals the generation mechanism of SSD cracks. Since mechanical processing inevitably causes a damaged layer on the surface of the hemispherical resonator, the damaged layer is mainly composed of surface cracks and SSD cracks that the surface cracks penetrate the interior of the material. In the vibration process of the hemispherical resonator, the SSD cracks significantly reduce the quality-factor, thus affecting the performance of HRGs. Second, by analyzing the stress field at the tip of the SSD cracks, a frictional energy dissipation model of SSD cracks was constructed, which reveals the effect of the SSD cracks on the quality-factor. Subsequently, a method for enhancing the quality-factor through chemical etching was proposed. The quality-factor enhancement method examines the passivation mechanism of SSD cracks during chemical etching. This process effectively reduces the length of the SSD cracks and increases the spacing between crack interfaces. These changes minimize frictional energy dissipation, thereby improving the quality-factor of hemispherical resonators. Finally, the experimental results of chemical etching and vibration performance of hemispherical resonators show that the SSD cracks are significantly improved after chemical etching and the quality-factor is improved from 1 × 105 to 2 × 107. The experimental results demonstrate the correctness of the energy dissipation mechanism affecting the quality-factor and the effectiveness of the quality-factor enhancement method.
{"title":"Energy dissipation mechanism and quality-factor enhancement method in hemispherical resonator","authors":"Ning Wang, Zhennan Wei, Zeyuan Xu, Guoxing Yi, Lishan Yuan, Wenyue Zhao, Dongfang Zhao","doi":"10.1016/j.ijmecsci.2024.109912","DOIUrl":"https://doi.org/10.1016/j.ijmecsci.2024.109912","url":null,"abstract":"The quality-factor of hemispherical resonators is one of the important factors affecting the precision and performance of hemispherical resonator gyroscopes (HRGs). This study investigates the generation mechanism of subsurface damage (SSD) cracks in hemispherical resonators and their impact on the quality-factor, proposing a chemical etching method to enhance the quality-factor. First, a grinding model of a rotating grinding wheel was established based on indentation fracture theory, which reveals the generation mechanism of SSD cracks. Since mechanical processing inevitably causes a damaged layer on the surface of the hemispherical resonator, the damaged layer is mainly composed of surface cracks and SSD cracks that the surface cracks penetrate the interior of the material. In the vibration process of the hemispherical resonator, the SSD cracks significantly reduce the quality-factor, thus affecting the performance of HRGs. Second, by analyzing the stress field at the tip of the SSD cracks, a frictional energy dissipation model of SSD cracks was constructed, which reveals the effect of the SSD cracks on the quality-factor. Subsequently, a method for enhancing the quality-factor through chemical etching was proposed. The quality-factor enhancement method examines the passivation mechanism of SSD cracks during chemical etching. This process effectively reduces the length of the SSD cracks and increases the spacing between crack interfaces. These changes minimize frictional energy dissipation, thereby improving the quality-factor of hemispherical resonators. Finally, the experimental results of chemical etching and vibration performance of hemispherical resonators show that the SSD cracks are significantly improved after chemical etching and the quality-factor is improved from 1 × 10<ce:sup loc=\"post\">5</ce:sup> to 2 × 10<ce:sup loc=\"post\">7</ce:sup>. The experimental results demonstrate the correctness of the energy dissipation mechanism affecting the quality-factor and the effectiveness of the quality-factor enhancement method.","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"37 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142929213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-12-27DOI: 10.1016/j.ijmecsci.2024.109913
Liming Huang, Hongyuan Wan, Quanfeng Han, Jianxiang Wang, Xin Yi
Additive manufacturing has enabled the creation of lattice structures with tunable properties, making them increasingly popular across various industries. However, their fatigue resistance remains a critical concern for long-term use. While contour scanning, a remelting technique in selective laser melting, improves surface quality and mechanical properties in tensile specimens, its effect on the fatigue behavior of as-built lattices remains underexplored. This study characterizes the manufacturing defects and intricate geometry of 316L skeletal gyroid lattice structures and investigates the impact of contour scanning on their compression-compression fatigue behavior through experimental and numerical approaches. The results show a significant improvement in high-cycle fatigue endurance due to contour scanning, attributed to enhanced surface smoothness. Cyclic ratcheting is identified as the dominant fatigue mechanism in both gyroid samples, with and without contour scanning. Additionally, fatigue life predictions based on finite element analysis, informed by experimental fatigue data and Basquin's equation, align well with experimental results. This work underscores the importance of contour scanning in enhancing the fatigue performance of lattice structures.
{"title":"Mitigating surface notches for enhanced fatigue performance of metallic gyroid structures via contour scanning","authors":"Liming Huang, Hongyuan Wan, Quanfeng Han, Jianxiang Wang, Xin Yi","doi":"10.1016/j.ijmecsci.2024.109913","DOIUrl":"https://doi.org/10.1016/j.ijmecsci.2024.109913","url":null,"abstract":"Additive manufacturing has enabled the creation of lattice structures with tunable properties, making them increasingly popular across various industries. However, their fatigue resistance remains a critical concern for long-term use. While contour scanning, a remelting technique in selective laser melting, improves surface quality and mechanical properties in tensile specimens, its effect on the fatigue behavior of as-built lattices remains underexplored. This study characterizes the manufacturing defects and intricate geometry of 316L skeletal gyroid lattice structures and investigates the impact of contour scanning on their compression-compression fatigue behavior through experimental and numerical approaches. The results show a significant improvement in high-cycle fatigue endurance due to contour scanning, attributed to enhanced surface smoothness. Cyclic ratcheting is identified as the dominant fatigue mechanism in both gyroid samples, with and without contour scanning. Additionally, fatigue life predictions based on finite element analysis, informed by experimental fatigue data and Basquin's equation, align well with experimental results. This work underscores the importance of contour scanning in enhancing the fatigue performance of lattice structures.","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"107 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142929214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-12-24DOI: 10.1016/j.ijmecsci.2024.109905
Tom Fisher, Zafer Kazancı, José Humberto S. Almeida Jr.
This study explores the high-velocity impact response of 3D-printed composite mechanical metamaterials through a combination of experimental testing and numerical simulations. Auxetic structures demonstrated a marked reduction in transmitted force and an extended force duration, both of which are advantageous for mitigating impact-related injuries. Specifically, the double arrowhead auxetic geometry reduced the transmitted force by 44% compared to conventional hexagonal structures, albeit at the cost of 17% greater deformation. Novel hybrid designs, integrating auxetic and conventional geometries, achieved a decoupled control of deformation and force responses. For instance, a re-entrant auxetic structure on the impact face, transitioning into a hexagonal configuration, led to a 10% increase in deformation compared to the reverse orientation while maintaining a similar transmitted force. Additionally, a comprehensive parametric study was conducted to examine the influence of cell size and relative density on the overall impact performance of these metamaterials.
{"title":"High-velocity impact response of 3D-printed composite mechanical metamaterials","authors":"Tom Fisher, Zafer Kazancı, José Humberto S. Almeida Jr.","doi":"10.1016/j.ijmecsci.2024.109905","DOIUrl":"https://doi.org/10.1016/j.ijmecsci.2024.109905","url":null,"abstract":"This study explores the high-velocity impact response of 3D-printed composite mechanical metamaterials through a combination of experimental testing and numerical simulations. Auxetic structures demonstrated a marked reduction in transmitted force and an extended force duration, both of which are advantageous for mitigating impact-related injuries. Specifically, the double arrowhead auxetic geometry reduced the transmitted force by 44% compared to conventional hexagonal structures, albeit at the cost of 17% greater deformation. Novel hybrid designs, integrating auxetic and conventional geometries, achieved a decoupled control of deformation and force responses. For instance, a re-entrant auxetic structure on the impact face, transitioning into a hexagonal configuration, led to a 10% increase in deformation compared to the reverse orientation while maintaining a similar transmitted force. Additionally, a comprehensive parametric study was conducted to examine the influence of cell size and relative density on the overall impact performance of these metamaterials.","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"50 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142901908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-12-21DOI: 10.1016/j.ijmecsci.2024.109909
Karthik Ramalingam, S. Amir H. Motaman, Christian Haase, Ulrich Krupp
In this study, a Thermo-micro-mechanical (TMM) model to describe the viscoplastic flow of polycrystalline metallic materials was extended by integration of micromechanical damage. The original TMM model [1] incorporated the fundamentals of dislocation motions during metal deformation, using microstructural state variables (MSVs) for the statistical quantification of dislocations, represented through the dislocation density. These MSVs track dislocation evolution throughout deformation, allowing for the material behavior and mechanical properties in cold and warm regimes (up to 500 °C) to be derived as functions of these state variables. A key advantage of the TMM model is its ability to transfer MSVs across multi-step process chain simulations, thereby accounting for the deformation history of materials in subsequent processes. However, the previous model was limited to the plastic regime and cannot be applied to processes involving damage and fracture. The primary objective of the current study is to extend the TMM model to predict fracture and damage. Therefore, the Gurson-Tveergard-Needleman (GTN) model, a widely recognized micromechanical damage model, was integrated into the TMM model to describe the material behavior comprising plasticity, damage and fracture (D-TMM model). This integration introduces void fraction from the damage model as an additional state variable alongside the existing MSVs, thus enabling the transfer of both deformation history and damage accumulation across the process chain. The constitutive equations from both models are numerically integrated, and their parameters are calibrated for a commonly used micro-alloyed high strength construction steel – S700. The model is subsequently tested under isothermal conditions up to 500 °C, non-isothermal conditions, and across a range of strain rates.
{"title":"Thermo-micro-mechanical modeling of plasticity and damage in single-phase S700 steel","authors":"Karthik Ramalingam, S. Amir H. Motaman, Christian Haase, Ulrich Krupp","doi":"10.1016/j.ijmecsci.2024.109909","DOIUrl":"https://doi.org/10.1016/j.ijmecsci.2024.109909","url":null,"abstract":"In this study, a Thermo-micro-mechanical (TMM) model to describe the viscoplastic flow of polycrystalline metallic materials was extended by integration of micromechanical damage. The original TMM model [<ce:cross-ref ref>1</ce:cross-ref>] incorporated the fundamentals of dislocation motions during metal deformation, using microstructural state variables (MSVs) for the statistical quantification of dislocations, represented through the dislocation density. These MSVs track dislocation evolution throughout deformation, allowing for the material behavior and mechanical properties in cold and warm regimes (up to 500 °C) to be derived as functions of these state variables. A key advantage of the TMM model is its ability to transfer MSVs across multi-step process chain simulations, thereby accounting for the deformation history of materials in subsequent processes. However, the previous model was limited to the plastic regime and cannot be applied to processes involving damage and fracture. The primary objective of the current study is to extend the TMM model to predict fracture and damage. Therefore, the Gurson-Tveergard-Needleman (GTN) model, a widely recognized micromechanical damage model, was integrated into the TMM model to describe the material behavior comprising plasticity, damage and fracture (D-TMM model). This integration introduces void fraction from the damage model as an additional state variable alongside the existing MSVs, thus enabling the transfer of both deformation history and damage accumulation across the process chain. The constitutive equations from both models are numerically integrated, and their parameters are calibrated for a commonly used micro-alloyed high strength construction steel – S700. The model is subsequently tested under isothermal conditions up to 500 °C, non-isothermal conditions, and across a range of strain rates.","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"65 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142901850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-12-20DOI: 10.1016/j.ijmecsci.2024.109907
Zhi Zhang, Bo Song, Lei Zhang, Ruxuan Fang, Xiaobo Wang, Yonggang Yao, Gang Wu, Qiaojiao Li, Yusheng Shi
Lightweight metamaterials with high strength and superior heat insulation are crucial for hypersonic aircraft to resist mechanical and thermal shock under ultra-high speed conditions. However, an inverted relationship between mechanical properties and heat insulation leads to difficulties in their synergy improvement by controlling relative density. Therefore, innovative design of metamaterials for mechanical properties, heat insulation, and their successful fabrication are paramount, but often laborious because of the vast design space, associated complex mechanical-thermal physical models with spatial configuration, and their complex configuration with micron size. This work proposed a node optimization strategy for mechanical-heat insulation synergy improvement. Taking the previous bionic polyhedron metamaterial (BPM) imitated pomelo peel as an example, the node-optimized octahedron metamaterial (OCM) fabricated by laser powder bed fusion (LPBF) achieved superior heat insulation and high strength. Based on experiments and numerical simulations, the OCM with a unit cell size of 3 mm (OCM3) had equivalent thermal conductivity (ETC) of 0.72 W/(m·K) and 2.19 W/(m·K) at room temperature and 600 °C with 8 % relative density, respectively, its heat-shielding index was 77 % at the load plate with 370 °C in natural convection. Furthermore, the OCM3’s strength and Young's modulus were 23.71±0.75 MPa and 981.44±19.44 MPa at room temperature; At 600 °C, its strength and Young's modulus were 12.52±0.82 MPa and 376.97±12.78 MPa, respectively. The above finding will guide the design and optimization of metamaterials with high strength and exceptional heat insulation.
{"title":"A node-optimized metamaterial with high mechanical properties and heat insulation","authors":"Zhi Zhang, Bo Song, Lei Zhang, Ruxuan Fang, Xiaobo Wang, Yonggang Yao, Gang Wu, Qiaojiao Li, Yusheng Shi","doi":"10.1016/j.ijmecsci.2024.109907","DOIUrl":"https://doi.org/10.1016/j.ijmecsci.2024.109907","url":null,"abstract":"Lightweight metamaterials with high strength and superior heat insulation are crucial for hypersonic aircraft to resist mechanical and thermal shock under ultra-high speed conditions. However, an inverted relationship between mechanical properties and heat insulation leads to difficulties in their synergy improvement by controlling relative density. Therefore, innovative design of metamaterials for mechanical properties, heat insulation, and their successful fabrication are paramount, but often laborious because of the vast design space, associated complex mechanical-thermal physical models with spatial configuration, and their complex configuration with micron size. This work proposed a node optimization strategy for mechanical-heat insulation synergy improvement. Taking the previous bionic polyhedron metamaterial (BPM) imitated pomelo peel as an example, the node-optimized octahedron metamaterial (OCM) fabricated by laser powder bed fusion (LPBF) achieved superior heat insulation and high strength. Based on experiments and numerical simulations, the OCM with a unit cell size of 3 mm (OCM3) had equivalent thermal conductivity (ETC) of 0.72 W/(m·K) and 2.19 W/(m·K) at room temperature and 600 °C with 8 % relative density, respectively, its heat-shielding index was 77 % at the load plate with 370 °C in natural convection. Furthermore, the OCM3’s strength and Young's modulus were 23.71±0.75 MPa and 981.44±19.44 MPa at room temperature; At 600 °C, its strength and Young's modulus were 12.52±0.82 MPa and 376.97±12.78 MPa, respectively. The above finding will guide the design and optimization of metamaterials with high strength and exceptional heat insulation.","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"32 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142901909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-12-16DOI: 10.1016/j.ijmecsci.2024.109900
Chien-hong Lin
This work presents a unified unit-cell micromechanics model, a novel approach for effectively predicting the fully coupled thermo-magneto-electro-elastic properties of magnetoelectric composites with three connectivity types: 1–3, 0–3, and 2–2. Unlike traditional micromechanics models, the present model allows for the simultaneous modeling of multiple composite configurations while utilizing fewer representative elements, thereby enhancing computational efficiency without sacrificing prediction accuracy. The innovation lies in a distinctive unit cell configuration that utilizes the least number of subcells and dimension parameters. Numerical results are presented, including effective elastic, dielectric, piezoelectric, magnetic permeability, piezomagnetic, magnetoelectric moduli along with coefficient of thermal expansion and associated pyroelectric and pyromagnetic constants. Through comprehensive numerical simulations, the present model predictions are compared with established methods, such as the Mori-Tanaka, simplified unit-cell, and method of cells models, demonstrating its reliability and precision. The model efficacy is further validated by aligning its estimations with experimental data from various multifunctional composite materials. This study marks a significant advancement in micromechanics, offering a flexible and efficient framework for designing and analyzing advanced multifunctional composites.
{"title":"Unified micromechanics of magnetoelectric fibrous, particulate, and laminated composite materials","authors":"Chien-hong Lin","doi":"10.1016/j.ijmecsci.2024.109900","DOIUrl":"https://doi.org/10.1016/j.ijmecsci.2024.109900","url":null,"abstract":"This work presents a unified unit-cell micromechanics model, a novel approach for effectively predicting the fully coupled thermo-magneto-electro-elastic properties of magnetoelectric composites with three connectivity types: 1–3, 0–3, and 2–2. Unlike traditional micromechanics models, the present model allows for the simultaneous modeling of multiple composite configurations while utilizing fewer representative elements, thereby enhancing computational efficiency without sacrificing prediction accuracy. The innovation lies in a distinctive unit cell configuration that utilizes the least number of subcells and dimension parameters. Numerical results are presented, including effective elastic, dielectric, piezoelectric, magnetic permeability, piezomagnetic, magnetoelectric moduli along with coefficient of thermal expansion and associated pyroelectric and pyromagnetic constants. Through comprehensive numerical simulations, the present model predictions are compared with established methods, such as the Mori-Tanaka, simplified unit-cell, and method of cells models, demonstrating its reliability and precision. The model efficacy is further validated by aligning its estimations with experimental data from various multifunctional composite materials. This study marks a significant advancement in micromechanics, offering a flexible and efficient framework for designing and analyzing advanced multifunctional composites.","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"23 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Intergranular stress corrosion cracking (IGSCC) occurs in polycrystalline alloys, and this process is inherently stochastic. This study proposed a new approach to predict the service life of a component subjected to IGSCC considering the scatter of its processes due to microstructural inhomogeneity. First, the crack initiation, growth, and coalescence in IGSCC were stochastically modeled considering the influence of microstructural inhomogeneity on cracking behavior. Then, a time-evolution simulation was developed based on the models. In this simulation, the time and crack length were described using probability density functions. Hence, once a crack length reaches a certain critical value, a cumulative distribution function of the time to failure is obtained, which reveals the service life due to IGSCC. The developed simulation was applied to IGSCC of type 304 stainless steel in a simulated boiling water reactor environment. The simulation successfully reproduced the crack initiation event after the incubation period followed by repeated crack growth and coalescence events, which were characteristic of the entire IGSCC process, and the results agreed with those of another simulation that well reproduced previous experimental results. Furthermore, the critical crack was set at 5 mm long, and the service life distribution was obtained from a single calculation. The developed simulation based on the stochastic models is a sophisticated approach to predict the service life of a component considering crack initiation, growth, and coalescence. Hence, it is expected that the simulation contributes to ensuring long-term structural integrity.
{"title":"Stochastic model for intergranular stress corrosion cracking of stainless steel","authors":"Tomoyuki Fujii, Yuki Takeichi, Yoshinobu Shimamura","doi":"10.1016/j.ijmecsci.2024.109888","DOIUrl":"https://doi.org/10.1016/j.ijmecsci.2024.109888","url":null,"abstract":"Intergranular stress corrosion cracking (IGSCC) occurs in polycrystalline alloys, and this process is inherently stochastic. This study proposed a new approach to predict the service life of a component subjected to IGSCC considering the scatter of its processes due to microstructural inhomogeneity. First, the crack initiation, growth, and coalescence in IGSCC were stochastically modeled considering the influence of microstructural inhomogeneity on cracking behavior. Then, a time-evolution simulation was developed based on the models. In this simulation, the time and crack length were described using probability density functions. Hence, once a crack length reaches a certain critical value, a cumulative distribution function of the time to failure is obtained, which reveals the service life due to IGSCC. The developed simulation was applied to IGSCC of type 304 stainless steel in a simulated boiling water reactor environment. The simulation successfully reproduced the crack initiation event after the incubation period followed by repeated crack growth and coalescence events, which were characteristic of the entire IGSCC process, and the results agreed with those of another simulation that well reproduced previous experimental results. Furthermore, the critical crack was set at 5 mm long, and the service life distribution was obtained from a single calculation. The developed simulation based on the stochastic models is a sophisticated approach to predict the service life of a component considering crack initiation, growth, and coalescence. Hence, it is expected that the simulation contributes to ensuring long-term structural integrity.","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"14 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In wire sawing, the dynamic bending of flexible wire influences the sawing process and the sawn surface formation. Prediction and effective improvement of the sawn surface quality remain challenging because existing models cannot fully describe the spatio-temporal interactions between the wire and the workpiece. This study established a three-dimensional dynamic model of wire sawing considering the workpiece-wire geometrical and mechanical relationships. The model was used to simulate the spatial sawing trajectory of the wire during the sawing of a 4-inch sapphire wafer and predict the sawn surface morphology. The simulation results were validated by comparing the cross-sectional shape, wavelength, and peak-to-valley value (PV) of the saw marks generated from wire sawing experiments. It was found that the distribution of wavelength and PV of saw marks on the sawn surface was non-uniform in the feed direction, that the PV varied within 10∼24 μm and wavelengths varied within 0.32∼1 mm. Moreover, force analysis confirmed that the non-uniformity of wavelengths and PV was primarily influenced by the time-varying unit contact length feed force and lateral force. A saw marks control strategy based on varying wire reciprocation periods was proposed. Compared to the primitive process, the improved process reduced the maximum PV by 50 % and the maximum wavelength by 47 %, while the distribution uniformities of both on the sawn surface were also significantly improved. This study not only provides a new approach to improving sawn surfaces but also offers a practical analytical tool for understanding the evolution of the macroscopic sawing behavior of the flexible wire during the sawing process.
{"title":"Three-dimensional dynamic model of wire sawing for saw marks control","authors":"Zhiyuan Lai, Xinjiang Liao, Zhiteng Xu, Zhongwei Hu, Hui Huang","doi":"10.1016/j.ijmecsci.2024.109892","DOIUrl":"https://doi.org/10.1016/j.ijmecsci.2024.109892","url":null,"abstract":"In wire sawing, the dynamic bending of flexible wire influences the sawing process and the sawn surface formation. Prediction and effective improvement of the sawn surface quality remain challenging because existing models cannot fully describe the spatio-temporal interactions between the wire and the workpiece. This study established a three-dimensional dynamic model of wire sawing considering the workpiece-wire geometrical and mechanical relationships. The model was used to simulate the spatial sawing trajectory of the wire during the sawing of a 4-inch sapphire wafer and predict the sawn surface morphology. The simulation results were validated by comparing the cross-sectional shape, wavelength, and peak-to-valley value (PV) of the saw marks generated from wire sawing experiments. It was found that the distribution of wavelength and PV of saw marks on the sawn surface was non-uniform in the feed direction, that the PV varied within 10∼24 μm and wavelengths varied within 0.32∼1 mm. Moreover, force analysis confirmed that the non-uniformity of wavelengths and PV was primarily influenced by the time-varying unit contact length feed force and lateral force. A saw marks control strategy based on varying wire reciprocation periods was proposed. Compared to the primitive process, the improved process reduced the maximum PV by 50 % and the maximum wavelength by 47 %, while the distribution uniformities of both on the sawn surface were also significantly improved. This study not only provides a new approach to improving sawn surfaces but also offers a practical analytical tool for understanding the evolution of the macroscopic sawing behavior of the flexible wire during the sawing process.","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"2 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study proposes a novel VFM on a fiber scale to capture the ballistic behavior of 3DOWF. The model effectively reveals yarn deformation during the weaving process of fabric, and yarn pull-out, interfiber friction and yarn interactions during the ballistic response. The results revealed that the VFM exhibited a ballistic response consistent with high-speed photography observations and successfully captured fiber slippage and pull-out behavior under impact. Compared to the YM, the VFM enables the observation of nonsimultaneous fiber breakage and fiber interactions. Moreover, it illustrates the role of yarn pull-out in the penetration resistance of the 3DOWF, dissipating the kinetic energy of the projectile in the form of friction. Furthermore, the VFM delineated the specific functions of each system yarn. Specifically, the warp and weft yarns primarily serve as impediments to the projectile, whereas the Z yarn binds the weft, promoting the increased involvement of the weft in dissipating kinetic energy. Building on this investigation, the impact of the clamping method on the ballistic performance of the 3DOWF was explored. The findings revealed that yarn pullout emerged as the primary failure mode under the weft sides. Notably, the warp yarns predominantly experienced pullout, which enhanced the friction energy. The Z yarn binds to weft yarns that gather with warp yarns to form a strip-like protrusion, impeding the projectile motion owing to the increased number of yarns. The VFM contributes significantly to the exploration of the impact of fabric structures on ballistic performance, offering valuable insights for designing and enhancing ballistic fabric structures.
本研究提出了一种新颖的纤维尺度 VFM，以捕捉 3DOWF 的弹道行为。该模型有效揭示了织物织造过程中的纱线变形，以及弹道响应过程中的纱线拉出、纤维间摩擦和纱线相互作用。结果表明，VFM 的弹道响应与高速摄影观察结果一致，并成功捕捉到了冲击下的纤维滑动和拔出行为。与 YM 相比，VFM 可以观察到非同时发生的纤维断裂和纤维相互作用。此外，它还说明了纱线拉出在 3DOWF 抗穿透性中的作用，以摩擦的形式消散了弹丸的动能。此外，VFM 划分了每个系统纱线的特定功能。具体来说，经纱和纬纱主要起到阻碍弹丸的作用，而 Z 纱则结合纬纱，促进纬纱更多地参与动能耗散。在这项研究的基础上，我们探讨了夹纱方法对 3DOWF 弹道性能的影响。研究结果表明，纬纱侧的主要失效模式是纱线拉断。值得注意的是，经纱主要发生了拉断，这增强了摩擦能量。Z 纱与纬纱结合，纬纱与经纱聚集形成条状突起，由于纱线数量增加，阻碍了弹丸的运动。VFM 大大有助于探索织物结构对弹道性能的影响，为设计和改进弹道织物结构提供了宝贵的见解。
{"title":"Ballistic behavior of three-dimensional orthotropic woven fabric using virtual-fiber model","authors":"Jian Zhang, Yi Zhou, Zhenqian Lu, Jianing Yue, Jing Han, Kanghui Zhou, Shengkai Liu, Qian Jiang, Liwei Wu","doi":"10.1016/j.ijmecsci.2024.109896","DOIUrl":"https://doi.org/10.1016/j.ijmecsci.2024.109896","url":null,"abstract":"This study proposes a novel VFM on a fiber scale to capture the ballistic behavior of 3DOWF. The model effectively reveals yarn deformation during the weaving process of fabric, and yarn pull-out, interfiber friction and yarn interactions during the ballistic response. The results revealed that the VFM exhibited a ballistic response consistent with high-speed photography observations and successfully captured fiber slippage and pull-out behavior under impact. Compared to the YM, the VFM enables the observation of nonsimultaneous fiber breakage and fiber interactions. Moreover, it illustrates the role of yarn pull-out in the penetration resistance of the 3DOWF, dissipating the kinetic energy of the projectile in the form of friction. Furthermore, the VFM delineated the specific functions of each system yarn. Specifically, the warp and weft yarns primarily serve as impediments to the projectile, whereas the Z yarn binds the weft, promoting the increased involvement of the weft in dissipating kinetic energy. Building on this investigation, the impact of the clamping method on the ballistic performance of the 3DOWF was explored. The findings revealed that yarn pullout emerged as the primary failure mode under the weft sides. Notably, the warp yarns predominantly experienced pullout, which enhanced the friction energy. The Z yarn binds to weft yarns that gather with warp yarns to form a strip-like protrusion, impeding the projectile motion owing to the increased number of yarns. The VFM contributes significantly to the exploration of the impact of fabric structures on ballistic performance, offering valuable insights for designing and enhancing ballistic fabric structures.","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"1 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142825074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-12-09DOI: 10.1016/j.ijmecsci.2024.109891
Kai Zhao, Yu Ding, Haiyang Yu, Jianying He, Zhiliang Zhang
The plastic events occurring during the process of intergranular fracture in metals is still not well understood due to the complexity of grain boundary (GB) structures and their interactions with crack-tip dislocation plasticity. By considering the local GB structural transformation after dislocation emission from a GB in the Peierls-type Rice-Beltz model, herein we established a semi-analytical transition-state-theory-based framework to predict the most probable Mode-I stress intensity factor (SIF) for dislocation emission from a cracked GB. Using large-scale molecular dynamics (MD) simulations, we studied the fracture behaviors of bi-crystalline Fe samples with 12 different symmetric tilt GBs inside. The MD results demonstrate that the presence of GB could significantly change the SIF required for the activation of plastic events, confirming the theoretical predictions that attributes this to the energy change caused by the transformation of GB structure. Both the atomistic simulation and the theoretical model consistently indicate that, the critical dynamic SIF (KIc(t)) at which the dynamic SIF KI(t) deviates from the linearity with respect to the strain ε, increases with the increasing loading rate. However, the classical Rice model underestimates the KIc(t) due to its failure to consider the effects of localized fields. The present theoretical model provides a mechanism-based framework for the application of grain boundary engineering in the design and fabrication of nano-grained metals.
{"title":"An extended Rice model for intergranular fracture","authors":"Kai Zhao, Yu Ding, Haiyang Yu, Jianying He, Zhiliang Zhang","doi":"10.1016/j.ijmecsci.2024.109891","DOIUrl":"https://doi.org/10.1016/j.ijmecsci.2024.109891","url":null,"abstract":"The plastic events occurring during the process of intergranular fracture in metals is still not well understood due to the complexity of grain boundary (GB) structures and their interactions with crack-tip dislocation plasticity. By considering the local GB structural transformation after dislocation emission from a GB in the Peierls-type Rice-Beltz model, herein we established a semi-analytical transition-state-theory-based framework to predict the most probable Mode-I stress intensity factor (SIF) for dislocation emission from a cracked GB. Using large-scale molecular dynamics (MD) simulations, we studied the fracture behaviors of bi-crystalline Fe samples with 12 different symmetric tilt GBs inside. The MD results demonstrate that the presence of GB could significantly change the SIF required for the activation of plastic events, confirming the theoretical predictions that attributes this to the energy change caused by the transformation of GB structure. Both the atomistic simulation and the theoretical model consistently indicate that, the critical dynamic SIF (<mml:math altimg=\"si18.svg\"><mml:mrow><mml:msubsup><mml:mi>K</mml:mi><mml:mi>I</mml:mi><mml:mi>c</mml:mi></mml:msubsup><mml:mrow><mml:mo>(</mml:mo><mml:mi>t</mml:mi><mml:mo>)</mml:mo></mml:mrow></mml:mrow></mml:math>) at which the dynamic SIF <ce:italic>K<ce:inf loc=\"post\">I</ce:inf></ce:italic>(<ce:italic>t</ce:italic>) deviates from the linearity with respect to the strain ε, increases with the increasing loading rate. However, the classical Rice model underestimates the <mml:math altimg=\"si18.svg\"><mml:mrow><mml:msubsup><mml:mi>K</mml:mi><mml:mi>I</mml:mi><mml:mi>c</mml:mi></mml:msubsup><mml:mrow><mml:mo>(</mml:mo><mml:mi>t</mml:mi><mml:mo>)</mml:mo></mml:mrow></mml:mrow></mml:math> due to its failure to consider the effects of localized fields. The present theoretical model provides a mechanism-based framework for the application of grain boundary engineering in the design and fabrication of nano-grained metals.","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"250 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142825075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：