Pub Date : 2024-05-01DOI: 10.1177/10567895241245716
Santosh Reddy Kommidi, Yong-Rak Kim, Do-Gyoon Kim
Bone is a complex hierarchical structural material whose organ-level response is highly influenced by its constitutive behavior at the microstructural level, which can dictate the inelastic nonlinear deformation and fracture within the organ. In the current study, a combined experimental-computational approach was sought to first obtain the local constitutive properties. Later, a multiscale modeling framework utilizing a novel rate-dependent nonlinear viscoelastic cohesive zone (NVCZ) model was used to explore the fracture behavior at the microstructure of the bone and its influence on the global scale (organ-level) response. Toward this end, nanoindentation testing was conducted within the cross-section of a rat femur bone specimen. An inverse optimization process was used to identify the isotropic linear viscoelastic (LVE) properties of cortical bone by integrating the test results with a finite element model simulation of the nanoindentation testing. Model results using different numbers of spring-dashpot units in the generalized Maxwell model showed that four spring-dashpot units are sufficient to capture the LVE behavior, while solely LVE constitutive relation is limited to fully characterize the rat femur. The LVE constitutive properties were then used along with the rate-dependent NVCZ fracture within the representative volume element (RVE), which was two-way coupled to the global scale bone. A parametric study was conducted by varying the fracture properties of the NVCZ model. The model demonstrated the capability and features to represent inelastic deformation and nonlinear fracture that are linked between length scales. This further implies that the inelastic fracture model and the two-way coupled modeling can elucidate the complex multiscale deformation and fracture of bone, while model validation and further advancements with test results remain a follow-up study and are currently in progress.
{"title":"Modeling of viscoelastic deformation and rate-dependent fracture damage in rat bone","authors":"Santosh Reddy Kommidi, Yong-Rak Kim, Do-Gyoon Kim","doi":"10.1177/10567895241245716","DOIUrl":"https://doi.org/10.1177/10567895241245716","url":null,"abstract":"Bone is a complex hierarchical structural material whose organ-level response is highly influenced by its constitutive behavior at the microstructural level, which can dictate the inelastic nonlinear deformation and fracture within the organ. In the current study, a combined experimental-computational approach was sought to first obtain the local constitutive properties. Later, a multiscale modeling framework utilizing a novel rate-dependent nonlinear viscoelastic cohesive zone (NVCZ) model was used to explore the fracture behavior at the microstructure of the bone and its influence on the global scale (organ-level) response. Toward this end, nanoindentation testing was conducted within the cross-section of a rat femur bone specimen. An inverse optimization process was used to identify the isotropic linear viscoelastic (LVE) properties of cortical bone by integrating the test results with a finite element model simulation of the nanoindentation testing. Model results using different numbers of spring-dashpot units in the generalized Maxwell model showed that four spring-dashpot units are sufficient to capture the LVE behavior, while solely LVE constitutive relation is limited to fully characterize the rat femur. The LVE constitutive properties were then used along with the rate-dependent NVCZ fracture within the representative volume element (RVE), which was two-way coupled to the global scale bone. A parametric study was conducted by varying the fracture properties of the NVCZ model. The model demonstrated the capability and features to represent inelastic deformation and nonlinear fracture that are linked between length scales. This further implies that the inelastic fracture model and the two-way coupled modeling can elucidate the complex multiscale deformation and fracture of bone, while model validation and further advancements with test results remain a follow-up study and are currently in progress.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140819342","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 : 2024-05-01DOI: 10.1177/10567895241245859
Vladimir Dunić, Ryosuke Matsui, Kohei Takeda, Miroslav Živković
In practical applications, TiNi shape memory alloys (SMAs) exhibit behavior that can pose a challenge with current constitutive models and their implementations in finite element method (FEM) software. TiNi SMA devices typically operate in the forward or reverse martensitic transformation regime, which is known as subloop loading. During such cyclic loading–unloading, the hysteresis stress–strain loop changes because of material damage, which can be considered the fatigue of TiNi SMAs. During both the loading and unloading processes, the stress plateau decreases. At the same time, the accumulated (residual) martensitic transformation strain increases. In this study, the experimental investigation results and observations of the aforementioned phenomena are presented. Next, the phase-field damage model is employed, along with a modified Lagoudas constitutive model, to simulate the change in stress–strain hysteresis. Furthermore, a fatigue function is used to simulate the accumulation of martensitic transformation strain. The experimental stress–strain response is compared with the simulation results, and good quantitative and qualitative agreement is obtained. The damage and martensitic volume fraction with respect to strain are discussed for full-loop and subloop loading. The observations and conclusions, as well as open questions, are presented. Possible directions for future research are provided.
在实际应用中，钛镍形状记忆合金（SMA）表现出的行为可能会对当前的构成模型及其在有限元法（FEM）软件中的实施带来挑战。钛镍形状记忆合金（SMA）设备通常在正向或反向马氏体转变状态下工作，这被称为亚循环加载。在这种循环加载-卸载过程中，滞后应力-应变环会因材料损坏而发生变化，这可视为钛镍 SMA 的疲劳。在加载和卸载过程中，应力平台都会下降。同时，累积（残余）马氏体转变应变增加。本研究介绍了上述现象的实验研究结果和观察结果。接着，采用相场损伤模型和改进的拉古达斯构成模型模拟应力-应变滞后的变化。此外，还使用疲劳函数来模拟马氏体转变应变的积累。实验应力-应变响应与模拟结果进行了比较，结果在定量和定性方面都非常吻合。讨论了全环和亚环加载时损伤和马氏体体积分数与应变的关系。提出了观察结果和结论，以及有待解决的问题。还提供了未来可能的研究方向。
{"title":"Phase-field damage simulation of subloop loading in TiNi SMA","authors":"Vladimir Dunić, Ryosuke Matsui, Kohei Takeda, Miroslav Živković","doi":"10.1177/10567895241245859","DOIUrl":"https://doi.org/10.1177/10567895241245859","url":null,"abstract":"In practical applications, TiNi shape memory alloys (SMAs) exhibit behavior that can pose a challenge with current constitutive models and their implementations in finite element method (FEM) software. TiNi SMA devices typically operate in the forward or reverse martensitic transformation regime, which is known as subloop loading. During such cyclic loading–unloading, the hysteresis stress–strain loop changes because of material damage, which can be considered the fatigue of TiNi SMAs. During both the loading and unloading processes, the stress plateau decreases. At the same time, the accumulated (residual) martensitic transformation strain increases. In this study, the experimental investigation results and observations of the aforementioned phenomena are presented. Next, the phase-field damage model is employed, along with a modified Lagoudas constitutive model, to simulate the change in stress–strain hysteresis. Furthermore, a fatigue function is used to simulate the accumulation of martensitic transformation strain. The experimental stress–strain response is compared with the simulation results, and good quantitative and qualitative agreement is obtained. The damage and martensitic volume fraction with respect to strain are discussed for full-loop and subloop loading. The observations and conclusions, as well as open questions, are presented. Possible directions for future research are provided.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140819438","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 : 2024-05-01DOI: 10.1177/10567895241247324
Can Du, Jing Bi, Yu Zhao, Chaolin Wang, Wei Tang, Shuailong Lian
Liquid nitrogen (LN2) can be utilized in the development of enhanced geothermal systems, as well as for deep/ultra-deep hydrocarbon reservoir stimulation, fire suppression, and other high-temperature geological projects. It is a crucial issue in the utilization of LN2 to investigate the pore structure evolution, permeability, and damage characteristics of high-temperature rocks under the influence of LN2 cooling shock. These rocks were first slowly heated to 150∼600°C and held for 2 h, followed by LN2 or natural cooling. The evolution of pore volume in high-temperature rocks affected by liquid nitrogen cooling was quantified. T2 cutoff values were determined through centrifugal tests, while the contents of irreducible and mobile fluids were estimated. Based on the aforementioned analysis as well as changes in irreducible fluid saturation, pore throat, tortuosity, and permeability, this study examines the closure and development of pores along with permeability behavior. The findings suggest that, despite a more pronounced decrease in porosity at lower heating temperatures, LN2 cooling specimens exhibit superior pore connectivity and permeability compared to those cooled naturally. LN2 stimulation not only induces crack initiation and propagation but also results in further cooling induced densification based on heating densification. 225°C is considered to be the optimal temperature for cooling contraction induced densification in this study. At higher heating temperatures, the damage to rock cooled with LN2 is more severe than that of naturally cooled. This results in a greater increase in porosity, movable fluid content and proportion, and permeability of LN2 cooled specimens compared to naturally cooled specimens. The damage mechanism can be better understood by the constructed damage model that coordinates the pore increase/decrease and mutual pore transformation from the perspective of pore evolution.
{"title":"Investigation of pore structure evolution and damage characteristics of high temperature rocks subjected to liquid nitrogen cooling shock","authors":"Can Du, Jing Bi, Yu Zhao, Chaolin Wang, Wei Tang, Shuailong Lian","doi":"10.1177/10567895241247324","DOIUrl":"https://doi.org/10.1177/10567895241247324","url":null,"abstract":"Liquid nitrogen (LN<jats:sub>2</jats:sub>) can be utilized in the development of enhanced geothermal systems, as well as for deep/ultra-deep hydrocarbon reservoir stimulation, fire suppression, and other high-temperature geological projects. It is a crucial issue in the utilization of LN<jats:sub>2</jats:sub> to investigate the pore structure evolution, permeability, and damage characteristics of high-temperature rocks under the influence of LN<jats:sub>2</jats:sub> cooling shock. These rocks were first slowly heated to 150∼600°C and held for 2 h, followed by LN<jats:sub>2</jats:sub> or natural cooling. The evolution of pore volume in high-temperature rocks affected by liquid nitrogen cooling was quantified. T<jats:sub>2</jats:sub> cutoff values were determined through centrifugal tests, while the contents of irreducible and mobile fluids were estimated. Based on the aforementioned analysis as well as changes in irreducible fluid saturation, pore throat, tortuosity, and permeability, this study examines the closure and development of pores along with permeability behavior. The findings suggest that, despite a more pronounced decrease in porosity at lower heating temperatures, LN<jats:sub>2</jats:sub> cooling specimens exhibit superior pore connectivity and permeability compared to those cooled naturally. LN<jats:sub>2</jats:sub> stimulation not only induces crack initiation and propagation but also results in further cooling induced densification based on heating densification. 225°C is considered to be the optimal temperature for cooling contraction induced densification in this study. At higher heating temperatures, the damage to rock cooled with LN<jats:sub>2</jats:sub> is more severe than that of naturally cooled. This results in a greater increase in porosity, movable fluid content and proportion, and permeability of LN<jats:sub>2</jats:sub> cooled specimens compared to naturally cooled specimens. The damage mechanism can be better understood by the constructed damage model that coordinates the pore increase/decrease and mutual pore transformation from the perspective of pore evolution.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140819366","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}
In this study, the variation in the expansion displacement of concrete samples with different water-cement ratios under five corrosion solutions (single sulfate salt and coupled sulfate-chloride salt) is explored. The expansion displacement evolution of these concrete samples under sulfate corrosion (single salt corrosion) and sulfate-chloride corrosion (double salt corrosion) is comprehensively examined. The results reveal that the continuous accumulation of corrosion damage eventually manifests in the form of expansion displacement. Based on the experimental results and the chemical reaction rate equation of the delayed ettringite formation and Friedel’s salt generation, an evolution model of expansion force is established. According to this model and the Weibull distribution law of damage, a expansion displacement mechanics model is proposed to predict the expansion displacement behavior of concrete under sulfate corrosion as well as combined sulfate-chloride corrosion.
{"title":"Expansion displacement mechanics model of concrete under seawater corrosion","authors":"Tingwei Chen, Jinhan Chen, Jiankang Chen, Yunfeng Lv","doi":"10.1177/10567895241245877","DOIUrl":"https://doi.org/10.1177/10567895241245877","url":null,"abstract":"In this study, the variation in the expansion displacement of concrete samples with different water-cement ratios under five corrosion solutions (single sulfate salt and coupled sulfate-chloride salt) is explored. The expansion displacement evolution of these concrete samples under sulfate corrosion (single salt corrosion) and sulfate-chloride corrosion (double salt corrosion) is comprehensively examined. The results reveal that the continuous accumulation of corrosion damage eventually manifests in the form of expansion displacement. Based on the experimental results and the chemical reaction rate equation of the delayed ettringite formation and Friedel’s salt generation, an evolution model of expansion force is established. According to this model and the Weibull distribution law of damage, a expansion displacement mechanics model is proposed to predict the expansion displacement behavior of concrete under sulfate corrosion as well as combined sulfate-chloride corrosion.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140819212","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 : 2024-04-23DOI: 10.1177/10567895241247996
Aiqing Xu, Xiaoyan Man, J Woody Ju
A multiscale micromechanics-based progressive damage model is developed to investigate the overall mechanical behavior and the interfacial microcrack evolutions of the cementitious composites featuring superabsorbent polymer (SAP) under uniaxial tension. Elastic properties, progressive damage process, and homogenization procedure of cementitious composites are systematically integrated in this model. The effective elastic moduli of the composites are determined based on a multiscale micromechanical framework. According to the small strain assumption, the total strain tensor and the elastic-damage compliance tensor are additively decomposed into elastic and damage-induced components. The damage-induced strains and compliances are then deduced from micromechanics. To characterize the progressive elastic-damage induced by microcracks, stages of microcrack propagation are identified from the interface contact stress and the matrix cleavage stress. The complex potentials and stress intensity factors for kinked interface cracks are derived from the distributed dislocations method. By implementing the homogenization process, the macroscopic mechanical behavior is obtained from the micro/mesoscale. The results indicate that the material parameters have clear mechanical significance. Different parameters, such as the SAP addition ratio, aggregate content, initial interfacial crack size, and initial interfacial crack location, are revealed to be influential in the overall mechanical behavior of the composites. The proposed model can be generalized to other particle-reinforced composites with different constituent properties, which can potentially contribute to the design and optimization of durable composites.
本研究建立了一个基于多尺度微观力学的渐进损伤模型，用于研究单轴拉伸条件下以超吸收聚合物（SAP）为特征的水泥基复合材料的整体力学行为和界面微裂纹演变。该模型系统地整合了水泥基复合材料的弹性特性、渐进损伤过程和均质化程序。复合材料的有效弹性模量是基于多尺度微观力学框架确定的。根据小应变假设，总应变张量和弹性-损伤顺应性张量被加法分解为弹性成分和损伤诱导成分。然后从微力学推导出损伤诱导应变和顺应性。为了描述微裂缝引起的渐进弹性损伤，可从界面接触应力和基体裂缝应力中确定微裂缝扩展的阶段。通过分布式位错法推导出了扭结界面裂纹的复势和应力强度因子。通过均质化处理，可以从微观/宏观尺度获得宏观力学行为。结果表明，材料参数具有明显的力学意义。不同的参数，如 SAP 添加比、骨料含量、初始界面裂纹尺寸和初始界面裂纹位置，都对复合材料的整体力学行为有影响。所提出的模型可以推广到其他具有不同成分特性的颗粒增强复合材料，从而为耐用复合材料的设计和优化做出潜在贡献。
{"title":"A multiscale micromechanical progressive elastic-damage model for cementitious composites featuring superabsorbent polymer (SAP)","authors":"Aiqing Xu, Xiaoyan Man, J Woody Ju","doi":"10.1177/10567895241247996","DOIUrl":"https://doi.org/10.1177/10567895241247996","url":null,"abstract":"A multiscale micromechanics-based progressive damage model is developed to investigate the overall mechanical behavior and the interfacial microcrack evolutions of the cementitious composites featuring superabsorbent polymer (SAP) under uniaxial tension. Elastic properties, progressive damage process, and homogenization procedure of cementitious composites are systematically integrated in this model. The effective elastic moduli of the composites are determined based on a multiscale micromechanical framework. According to the small strain assumption, the total strain tensor and the elastic-damage compliance tensor are additively decomposed into elastic and damage-induced components. The damage-induced strains and compliances are then deduced from micromechanics. To characterize the progressive elastic-damage induced by microcracks, stages of microcrack propagation are identified from the interface contact stress and the matrix cleavage stress. The complex potentials and stress intensity factors for kinked interface cracks are derived from the distributed dislocations method. By implementing the homogenization process, the macroscopic mechanical behavior is obtained from the micro/mesoscale. The results indicate that the material parameters have clear mechanical significance. Different parameters, such as the SAP addition ratio, aggregate content, initial interfacial crack size, and initial interfacial crack location, are revealed to be influential in the overall mechanical behavior of the composites. The proposed model can be generalized to other particle-reinforced composites with different constituent properties, which can potentially contribute to the design and optimization of durable composites.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140636981","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 : 2024-04-20DOI: 10.1177/10567895241245754
Jinhui Guo, Yousong Xue, Bohong Gu, Baozhong Sun
Defect effects of carbon fiber composites under dynamic impact conditions are important to mechanical behavior design in the aerospace field. Here we report the defect effect on the impact compressive behavior of 3D braided composites at high strain rates from 550/s to 1240/s. The defect effect on damage behavior was observed by high-speed photography and digital image correlation (DIC) technology. A finite element analysis (FEA) model was developed to show the defect effect on stress distribution and thermo-mechanical behavior. The defect structure reduces the compressive strength of the composite and causes more brittle and catastrophic failure compared with the perfect composite. The defect effect on the compressive behaviors is more significant at higher strain rates. FEA results show that the defect structure causes local stress concentration, high adiabatic temperature rise, and high stress in the X-shaped shear band region, thereby accelerating composite failure.
碳纤维复合材料在动态冲击条件下的缺陷效应对航空航天领域的机械性能设计非常重要。在此，我们报告了缺陷对三维编织复合材料在 550/s 至 1240/s 高应变速率下冲击压缩行为的影响。通过高速摄影和数字图像相关（DIC）技术观察了缺陷对损伤行为的影响。建立的有限元分析（FEA）模型显示了缺陷对应力分布和热机械行为的影响。与完美的复合材料相比，缺陷结构降低了复合材料的抗压强度，导致更多的脆性和灾难性破坏。在应变速率较高时，缺陷对抗压行为的影响更为显著。有限元分析结果表明，缺陷结构会导致局部应力集中、绝热温升高以及 X 形剪切带区域的高应力，从而加速复合材料失效。
{"title":"Defect effect on high strain rate compressive behaviors of 3D braided composites","authors":"Jinhui Guo, Yousong Xue, Bohong Gu, Baozhong Sun","doi":"10.1177/10567895241245754","DOIUrl":"https://doi.org/10.1177/10567895241245754","url":null,"abstract":"Defect effects of carbon fiber composites under dynamic impact conditions are important to mechanical behavior design in the aerospace field. Here we report the defect effect on the impact compressive behavior of 3D braided composites at high strain rates from 550/s to 1240/s. The defect effect on damage behavior was observed by high-speed photography and digital image correlation (DIC) technology. A finite element analysis (FEA) model was developed to show the defect effect on stress distribution and thermo-mechanical behavior. The defect structure reduces the compressive strength of the composite and causes more brittle and catastrophic failure compared with the perfect composite. The defect effect on the compressive behaviors is more significant at higher strain rates. FEA results show that the defect structure causes local stress concentration, high adiabatic temperature rise, and high stress in the X-shaped shear band region, thereby accelerating composite failure.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140622799","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 : 2024-04-19DOI: 10.1177/10567895241245501
George Z Voyiadjis, Peter I Kattan
This work focuses on the dissection of the damage variable within solid materials. The underlying assumption is that damage within a solid primarily stems from the presence of various defects. The conventional approach to breaking down the damage variable into two parts – one attributed to the first defect type and the other to the second defect type – is both explored and expanded in a coherent mathematical manner. Within this context, a novel and asymmetric dissection of the damage variable is formulated. This fresh asymmetrical approach presents an alternative to the traditional symmetric dissection of the damage variable. Initially, the dissection considerations are carried out in a one-dimensional context using scalar values. However, this methodology is subsequently generalized employing tensors. In the end, an illustrative example is demonstrated.
{"title":"A new unsymmetrical decomposition of the damage variable","authors":"George Z Voyiadjis, Peter I Kattan","doi":"10.1177/10567895241245501","DOIUrl":"https://doi.org/10.1177/10567895241245501","url":null,"abstract":"This work focuses on the dissection of the damage variable within solid materials. The underlying assumption is that damage within a solid primarily stems from the presence of various defects. The conventional approach to breaking down the damage variable into two parts – one attributed to the first defect type and the other to the second defect type – is both explored and expanded in a coherent mathematical manner. Within this context, a novel and asymmetric dissection of the damage variable is formulated. This fresh asymmetrical approach presents an alternative to the traditional symmetric dissection of the damage variable. Initially, the dissection considerations are carried out in a one-dimensional context using scalar values. However, this methodology is subsequently generalized employing tensors. In the end, an illustrative example is demonstrated.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140621537","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 : 2024-04-12DOI: 10.1177/10567895241245753
Qi Xian-yin, Geng Dian-dong, Xu Ming-zhe, Ke Ting
To investigate the mechanical properties and damage evolution law of layered shale under varying moisture contents, we conducted triaxial compression experiments on rock samples with different bedding angles and moisture levels. This study analyzed the variations in mechanical properties of layered shale under different conditions, and established a predicted model for elastic modulus based on different bedding angles and moisture content. Additionally, the damage constitutive model of layered shale was improved. The study revealed that shale’s mechanical properties display anisotropy, which is influenced by the bedding angles and moisture contents. The elastic modulus of the rock increases with the rise of bedding angle, exhibiting a ‘U’-shaped change. Conversely, the mechanical properties of rocks deteriorate, and their brittleness weakens with the increase in moisture content. When the confining pressure increased, the overall mechanical properties of shale were enhanced, and the influence of bedding on shale was weakened, but the deteriorating effect of water on rocks was hardly affected. Based on the above experiments, a predicted model of equivalent elastic modulus of shale considering the coupling effect of bedding and different moisture contents was proposed, which could effectively predict the elastic modulus of layered shale with different moisture content under different confining pressures. Furthermore, based on the predicted model of elastic modulus, an improved damage constitutive model of layered shale under triaxial loading was established, and the damage accumulation trend of layered shale was obtained, which showed an “S”-shaped change with strain. Under the coupling effect of bedding and different moisture contents, the damage of shale was advanced, but the accumulation rate of damage slowed down. With the increase of confining pressure, the influence of bedding and moisture content on the damage characteristics of shale decreased, and the damage curves under different conditions gradually tended to isotropy. The developed damage constitutive model for layered shale under different moisture contents provides theoretical support for the study of reservoir fracturing and wellbore stability.
{"title":"Experimental and damage model study of layered shale under different moisture contents","authors":"Qi Xian-yin, Geng Dian-dong, Xu Ming-zhe, Ke Ting","doi":"10.1177/10567895241245753","DOIUrl":"https://doi.org/10.1177/10567895241245753","url":null,"abstract":"To investigate the mechanical properties and damage evolution law of layered shale under varying moisture contents, we conducted triaxial compression experiments on rock samples with different bedding angles and moisture levels. This study analyzed the variations in mechanical properties of layered shale under different conditions, and established a predicted model for elastic modulus based on different bedding angles and moisture content. Additionally, the damage constitutive model of layered shale was improved. The study revealed that shale’s mechanical properties display anisotropy, which is influenced by the bedding angles and moisture contents. The elastic modulus of the rock increases with the rise of bedding angle, exhibiting a ‘U’-shaped change. Conversely, the mechanical properties of rocks deteriorate, and their brittleness weakens with the increase in moisture content. When the confining pressure increased, the overall mechanical properties of shale were enhanced, and the influence of bedding on shale was weakened, but the deteriorating effect of water on rocks was hardly affected. Based on the above experiments, a predicted model of equivalent elastic modulus of shale considering the coupling effect of bedding and different moisture contents was proposed, which could effectively predict the elastic modulus of layered shale with different moisture content under different confining pressures. Furthermore, based on the predicted model of elastic modulus, an improved damage constitutive model of layered shale under triaxial loading was established, and the damage accumulation trend of layered shale was obtained, which showed an “S”-shaped change with strain. Under the coupling effect of bedding and different moisture contents, the damage of shale was advanced, but the accumulation rate of damage slowed down. With the increase of confining pressure, the influence of bedding and moisture content on the damage characteristics of shale decreased, and the damage curves under different conditions gradually tended to isotropy. The developed damage constitutive model for layered shale under different moisture contents provides theoretical support for the study of reservoir fracturing and wellbore stability.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140550456","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 : 2024-03-18DOI: 10.1177/10567895241235351
Yooseob Song, Jaeheum Yeon, George Z Voyiadjis
A constitutive model for C45 steel alloys is proposed in this work by integrating the effect of damage and a specific phenomenon, so-called dynamic strain aging. For damage modeling, an energy-based isotropic damage model is implemented within a frame of continuum damage mechanics. The total stress is decomposed into athermal and thermal elements. The former includes the additional term for dynamic strain aging. This term is conceptually inspired by the probabilistic nature of dynamic strain aging, and its derivation is micromechanics-based. Both athermal and thermal components are defined as a function of temperature, equivalent plastic strain, and equivalent plastic strain rate because the occurrence and characteristics of dynamic strain aging are dependent on these factors. A finite element solution for the developed model is addressed additionally to further investigate the characteristics of plastic-damage behaviors and dynamic strain aging. The numerical results are compared to the experiments and theoretical predictions for its validation. The modified model developed in this work has largely reduced the number of fitting parameters compared to the previous model originally developed by the authors in 2019. Nevertheless, predictions from the proposed model still capture the experimental data accurately.
{"title":"Theoretical and numerical modeling of the effect of damage and dynamic strain aging on the plastic response of C45 steel alloys","authors":"Yooseob Song, Jaeheum Yeon, George Z Voyiadjis","doi":"10.1177/10567895241235351","DOIUrl":"https://doi.org/10.1177/10567895241235351","url":null,"abstract":"A constitutive model for C45 steel alloys is proposed in this work by integrating the effect of damage and a specific phenomenon, so-called dynamic strain aging. For damage modeling, an energy-based isotropic damage model is implemented within a frame of continuum damage mechanics. The total stress is decomposed into athermal and thermal elements. The former includes the additional term for dynamic strain aging. This term is conceptually inspired by the probabilistic nature of dynamic strain aging, and its derivation is micromechanics-based. Both athermal and thermal components are defined as a function of temperature, equivalent plastic strain, and equivalent plastic strain rate because the occurrence and characteristics of dynamic strain aging are dependent on these factors. A finite element solution for the developed model is addressed additionally to further investigate the characteristics of plastic-damage behaviors and dynamic strain aging. The numerical results are compared to the experiments and theoretical predictions for its validation. The modified model developed in this work has largely reduced the number of fitting parameters compared to the previous model originally developed by the authors in 2019. Nevertheless, predictions from the proposed model still capture the experimental data accurately.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140161881","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 : 2024-03-08DOI: 10.1177/10567895241233836
Kai Chen, Roberto Cudmani, Andres Alfonso Pena Olarte
The study of constitutive relationship and damage degradation is crucial in solving the stability challenges faced in the rock engineering. In this work, the stress-strain relationships of different type of rocks subjected to uniaxial loading processes are investigated in details. Experimental results demonstrate measurements, such as uniaxial compressive strength (UCS), tangent deformation modulus, peak strain, and Poisson’s ratio ([Formula: see text]). A novel piecewise constitutive model is proposed that utilizes both a constitutive model during compaction and a conventional damage model using the strain equivalence assumption and logistic growth theory to represent the characteristics of stress-deformation curves during both compaction and post-compaction stages. The performance of the proposed constitutive models in capturing deformation characteristics of damaged rocks is demonstrated to be more outstanding in comparison to existing models. In all experimental cases discussed in this study, the proposed model outperforms existing reference models in terms of the coefficients of determination ([Formula: see text]), with the former having coefficients of determination greater than 0.95. Furthermore, physical meanings of relevant model parameters are found to be closely associated with properties of experimental stress-strain curves.
{"title":"Mechanical impairment characteristics and a novel constitutive model for rocks subjected to uniaxial loading process","authors":"Kai Chen, Roberto Cudmani, Andres Alfonso Pena Olarte","doi":"10.1177/10567895241233836","DOIUrl":"https://doi.org/10.1177/10567895241233836","url":null,"abstract":"The study of constitutive relationship and damage degradation is crucial in solving the stability challenges faced in the rock engineering. In this work, the stress-strain relationships of different type of rocks subjected to uniaxial loading processes are investigated in details. Experimental results demonstrate measurements, such as uniaxial compressive strength (UCS), tangent deformation modulus, peak strain, and Poisson’s ratio ([Formula: see text]). A novel piecewise constitutive model is proposed that utilizes both a constitutive model during compaction and a conventional damage model using the strain equivalence assumption and logistic growth theory to represent the characteristics of stress-deformation curves during both compaction and post-compaction stages. The performance of the proposed constitutive models in capturing deformation characteristics of damaged rocks is demonstrated to be more outstanding in comparison to existing models. In all experimental cases discussed in this study, the proposed model outperforms existing reference models in terms of the coefficients of determination ([Formula: see text]), with the former having coefficients of determination greater than 0.95. Furthermore, physical meanings of relevant model parameters are found to be closely associated with properties of experimental stress-strain curves.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140067631","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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