Pub Date : 2024-10-22DOI: 10.1177/10567895241292748
Lubo Meng, Shan Zhang, Tianbin Li, Tianyi Liu, Haoyu Li
The failure of layered rock after high temperature exposure is a major concern in deep underground engineering projects. This paper proposes an improved Nishihara creep constitutive model that considers damage factors and the bedding angle, which overcomes the shortcomings of the deviation in the description of the conventional Nishihara model in the acceleration stage. The constitutive model is verified by the conventional triaxial creepiest. The theoretical curve has a high degree of fitting with the experimental curve. The experimental results show that a temperature of [Formula: see text] has an obvious influence on the steady creep rate and the creep strain of layered sandstone, and [Formula: see text] can be regarded as the temperature threshold for the long-term strength and change from anisotropic to isotropic of layered sandstone. The irreversible melting mixing phenomenon at the boundary of mineral particles with increasing temperature is the mechanism by which different treatment temperatures affect the anisotropy degree of layered rock.
{"title":"Study on the creep constitutive model of layered rockconsidering anisotropic and damage factors after hightemperature exposure","authors":"Lubo Meng, Shan Zhang, Tianbin Li, Tianyi Liu, Haoyu Li","doi":"10.1177/10567895241292748","DOIUrl":"https://doi.org/10.1177/10567895241292748","url":null,"abstract":"The failure of layered rock after high temperature exposure is a major concern in deep underground engineering projects. This paper proposes an improved Nishihara creep constitutive model that considers damage factors and the bedding angle, which overcomes the shortcomings of the deviation in the description of the conventional Nishihara model in the acceleration stage. The constitutive model is verified by the conventional triaxial creepiest. The theoretical curve has a high degree of fitting with the experimental curve. The experimental results show that a temperature of [Formula: see text] has an obvious influence on the steady creep rate and the creep strain of layered sandstone, and [Formula: see text] can be regarded as the temperature threshold for the long-term strength and change from anisotropic to isotropic of layered sandstone. The irreversible melting mixing phenomenon at the boundary of mineral particles with increasing temperature is the mechanism by which different treatment temperatures affect the anisotropy degree of layered rock.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":"8 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142487450","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 : 2024-10-21DOI: 10.1177/10567895241292750
Yuezong Yang, Zhushan Shao, Nannan Zhao, Kui Wu
The deterioration of rock material properties induced by seepage pressure is a serious danger to the stability of geotechnical engineering. The formation and propagation of microcracks is the primary cause of rock macro failure. This work proposes an damage-based analytical model to assess the impact of seepage pressure on the macro mechanical behaviors of rocks from the standpoint of micro fracture. A wing crack model serves as the foundation for the analytical model. This model has taken into account the impact of seepage pressure on the initiation and growth of wing cracks. The constitutive relation is constructed based on the equivalency connection of damage defined by strain and wing crack length. A comparison between the analytical results and the reported experimental data confirms the reasonableness of the analytical model. Investigations are conducted on the relationship between the macro mechanical behavior of rocks and micro fracture under various seepage pressures, confining pressures, and microscopic parameters. The findings demonstrate that the cracks growth is initially steady before becoming unstable. The growing process of wing cracks stops when they connect with one another, and friction between the crack surfaces takes over. The initiation and growth of wing cracks may be aided by the seepage pressure. As the wing crack propagates, the seepage pressure effect initially increases, then decreases, and eventually has practically no impact. The influence of seepage pressure on rock macro mechanical behavior is that with seepage pressure increasing, the initiation stress and peak stress decrease, but the residual stress is basically a constant. The rock micro fracture process is significantly influenced by confining pressures and microscopic factors, which in turn affect the macro mechanical behavior. The study’s findings offer a micro fracture foundation for comprehending how seepage pressure affects the macro mechanical behaviors of rocks.
{"title":"A damage-based analytical model to evaluate seepage pressure effect on rock macro mechanical behaviors from the perspective of micro-fracture","authors":"Yuezong Yang, Zhushan Shao, Nannan Zhao, Kui Wu","doi":"10.1177/10567895241292750","DOIUrl":"https://doi.org/10.1177/10567895241292750","url":null,"abstract":"The deterioration of rock material properties induced by seepage pressure is a serious danger to the stability of geotechnical engineering. The formation and propagation of microcracks is the primary cause of rock macro failure. This work proposes an damage-based analytical model to assess the impact of seepage pressure on the macro mechanical behaviors of rocks from the standpoint of micro fracture. A wing crack model serves as the foundation for the analytical model. This model has taken into account the impact of seepage pressure on the initiation and growth of wing cracks. The constitutive relation is constructed based on the equivalency connection of damage defined by strain and wing crack length. A comparison between the analytical results and the reported experimental data confirms the reasonableness of the analytical model. Investigations are conducted on the relationship between the macro mechanical behavior of rocks and micro fracture under various seepage pressures, confining pressures, and microscopic parameters. The findings demonstrate that the cracks growth is initially steady before becoming unstable. The growing process of wing cracks stops when they connect with one another, and friction between the crack surfaces takes over. The initiation and growth of wing cracks may be aided by the seepage pressure. As the wing crack propagates, the seepage pressure effect initially increases, then decreases, and eventually has practically no impact. The influence of seepage pressure on rock macro mechanical behavior is that with seepage pressure increasing, the initiation stress and peak stress decrease, but the residual stress is basically a constant. The rock micro fracture process is significantly influenced by confining pressures and microscopic factors, which in turn affect the macro mechanical behavior. The study’s findings offer a micro fracture foundation for comprehending how seepage pressure affects the macro mechanical behaviors of rocks.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":"86 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142486812","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 : 2024-10-17DOI: 10.1177/10567895241292749
Yuan Fang, Xu Yazhou
Fretting fatigue often occurs in the interfaces between components, subjected to complex multi-axial load states and high stress gradients at the contact edge region. For the prediction of fretting fatigue crack initiation and in-depth understanding of the crack initiation mechanism, it is essential to investigate the damage mechanisms across various scales and explore the underlying scale coupling mechanisms. By introducing a power-law based scale coupling relationship, a two-scale model of fretting fatigue crack initiation life is proposed by combining macroscopic continuum damage mechanics (CDM) with microscopic crystal plastic finite element method (CPFEM). The simulation results indicate that the predicted fretting fatigue initiation life shows better accuracy than the result predicted by single-scale CDM model. In case of low stress level the rate of accumulated dissipation energy can be clearly divided into two stages with turning points, whereas it exhibits a relatively uniform damage process under high stress level. Moreover, the proposed two-scale model partly provides physical explanation for fretting fatigue crack initiation based on the information from the microscale.
{"title":"Accumulated crystal plasticity dissipation energy driven continuum damage two-scale model for fretting fatigue initiation life","authors":"Yuan Fang, Xu Yazhou","doi":"10.1177/10567895241292749","DOIUrl":"https://doi.org/10.1177/10567895241292749","url":null,"abstract":"Fretting fatigue often occurs in the interfaces between components, subjected to complex multi-axial load states and high stress gradients at the contact edge region. For the prediction of fretting fatigue crack initiation and in-depth understanding of the crack initiation mechanism, it is essential to investigate the damage mechanisms across various scales and explore the underlying scale coupling mechanisms. By introducing a power-law based scale coupling relationship, a two-scale model of fretting fatigue crack initiation life is proposed by combining macroscopic continuum damage mechanics (CDM) with microscopic crystal plastic finite element method (CPFEM). The simulation results indicate that the predicted fretting fatigue initiation life shows better accuracy than the result predicted by single-scale CDM model. In case of low stress level the rate of accumulated dissipation energy can be clearly divided into two stages with turning points, whereas it exhibits a relatively uniform damage process under high stress level. Moreover, the proposed two-scale model partly provides physical explanation for fretting fatigue crack initiation based on the information from the microscale.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":"25 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142448782","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 : 2024-09-30DOI: 10.1177/10567895241277657
Hui Wang, Zhichao Xu, Hongyuan Huai, Yunteng Yin, Jiacong Zeng, Zhihao Du, Hang Zhou
In order to study the effects of crack inclination angle and loading rate on rock mechanical properties, creep characteristics, and failure characteristics. Taking homogeneous red sandstone with different fracture angles as the research object, uniaxial compression tests and uniaxial compression creep tests were conducted at different loading rates. The results showed that under the same fracture angle, the loading rate was positively correlated with the peak strength, elastic modulus, instantaneous strain, creep strain, and steady-state creep rate of the sample, while negatively correlated with the peak strain. At the same loading rate, the mechanical properties and creep properties of the sample were controlled by the crack inclination angle α. With the increase of α, the peak strength, peak strain, instantaneous strain, creep strain and steady-state creep rate decreased first and then increased, and the elastic modulus increased. On the basis of rock creep testing, it is also important to establish a creep model that conforms to the actual test situation for studying rock creep characteristics. However, many models currently used cannot accurately describe the three stages of rock creep, especially the accelerated creep stage. Therefore, based on Burgers elements, this paper introduces plastic damage bodies based on damage rates and software components based on fractional calculus, A new creep model was obtained and its rationality was verified through experimental results. The results showed that the fit between the model and experimental data was above 0.97, indicating that the model can better describe the three stages of rock creep, especially reflecting the non-linear characteristics of the accelerated creep stage.
{"title":"Experimental study on the mechanical properties of red sandstone with fractures under different loading rates","authors":"Hui Wang, Zhichao Xu, Hongyuan Huai, Yunteng Yin, Jiacong Zeng, Zhihao Du, Hang Zhou","doi":"10.1177/10567895241277657","DOIUrl":"https://doi.org/10.1177/10567895241277657","url":null,"abstract":"In order to study the effects of crack inclination angle and loading rate on rock mechanical properties, creep characteristics, and failure characteristics. Taking homogeneous red sandstone with different fracture angles as the research object, uniaxial compression tests and uniaxial compression creep tests were conducted at different loading rates. The results showed that under the same fracture angle, the loading rate was positively correlated with the peak strength, elastic modulus, instantaneous strain, creep strain, and steady-state creep rate of the sample, while negatively correlated with the peak strain. At the same loading rate, the mechanical properties and creep properties of the sample were controlled by the crack inclination angle α. With the increase of α, the peak strength, peak strain, instantaneous strain, creep strain and steady-state creep rate decreased first and then increased, and the elastic modulus increased. On the basis of rock creep testing, it is also important to establish a creep model that conforms to the actual test situation for studying rock creep characteristics. However, many models currently used cannot accurately describe the three stages of rock creep, especially the accelerated creep stage. Therefore, based on Burgers elements, this paper introduces plastic damage bodies based on damage rates and software components based on fractional calculus, A new creep model was obtained and its rationality was verified through experimental results. The results showed that the fit between the model and experimental data was above 0.97, indicating that the model can better describe the three stages of rock creep, especially reflecting the non-linear characteristics of the accelerated creep stage.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":"121 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142360550","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 : 2024-09-27DOI: 10.1177/10567895241282229
Abel Cherouat, Thierry Barriere, Hong Wang
In this study, a comprehensive investigation was conducted to explore the material extrusion process of NiTi shape-memory alloy-based bio-composite polymeric matrix. Polylactic acid PLA+ Stearic Acid polymeric matrix are performed in order to develop an environmentally friendly process for manufacturing feedstocks with [Formula: see text] nickel-titanium powders for employed in the 3D printing process. The additive manufacturing process based on the extrusion of materials will be studied at all stages (feedstock manufacturing with nickel-titanium powders, 3D printing of bio-composite green part, thermal debinding, and densification by solid-state diffusion) using experimental approaches, analytical approaches to predict printability index and thermo-physical analyses for the formulation of NiTi and biocomposite binders. Printing parameters were optimized by analysing the microstructure, rheological, mechanical properties of feedstock and 3D printed parts. Static mechanical tests will be performed in association with numerical modelling to study the evolution of damage for fully densified SMA specimens in order to describe the ductile failure of 3D printed specimens. Micromechanical phenomenological constitutive models are used in Finite Element software and which can account for the damage localization, initiation and damage growth based on continuum damage mechanics. The results of this study can be used to optimize the extrusion process parameters for different materials and can be helpful for researchers and industrialists to further explore and develop sustainable and eco-friendly materials.
本研究对基于镍钛形状记忆合金的生物复合聚合物基体的材料挤压工艺进行了全面调查。聚乳酸 PLA+ 硬脂酸聚合基体，以开发出一种环保型工艺，用于制造含有[配方：见正文]镍钛粉末的原料，并将其应用于三维打印工艺中。将利用实验方法、预测可打印性指数的分析方法以及镍钛和生物复合材料粘合剂配方的热物理分析方法，研究基于材料挤压的添加制造工艺的各个阶段（镍钛粉末原料制造、生物复合材料绿色部件的三维打印、热脱粘和固态扩散致密化）。通过分析原料和三维打印部件的微观结构、流变学和机械性能，对打印参数进行了优化。静态机械测试将与数值建模相结合，研究全致密 SMA 试样的损伤演变，以描述 3D 打印试样的韧性破坏。有限元软件中使用了微观机械现象学构成模型，该模型可在连续损伤力学的基础上解释损伤定位、起始和损伤增长。本研究的结果可用于优化不同材料的挤压工艺参数，并有助于研究人员和工业家进一步探索和开发可持续的环保材料。
{"title":"Experimental analysis of extrusion-based additive manufacturing process of bio-composite NiTi alloy","authors":"Abel Cherouat, Thierry Barriere, Hong Wang","doi":"10.1177/10567895241282229","DOIUrl":"https://doi.org/10.1177/10567895241282229","url":null,"abstract":"In this study, a comprehensive investigation was conducted to explore the material extrusion process of NiTi shape-memory alloy-based bio-composite polymeric matrix. Polylactic acid PLA+ Stearic Acid polymeric matrix are performed in order to develop an environmentally friendly process for manufacturing feedstocks with [Formula: see text] nickel-titanium powders for employed in the 3D printing process. The additive manufacturing process based on the extrusion of materials will be studied at all stages (feedstock manufacturing with nickel-titanium powders, 3D printing of bio-composite green part, thermal debinding, and densification by solid-state diffusion) using experimental approaches, analytical approaches to predict printability index and thermo-physical analyses for the formulation of NiTi and biocomposite binders. Printing parameters were optimized by analysing the microstructure, rheological, mechanical properties of feedstock and 3D printed parts. Static mechanical tests will be performed in association with numerical modelling to study the evolution of damage for fully densified SMA specimens in order to describe the ductile failure of 3D printed specimens. Micromechanical phenomenological constitutive models are used in Finite Element software and which can account for the damage localization, initiation and damage growth based on continuum damage mechanics. The results of this study can be used to optimize the extrusion process parameters for different materials and can be helpful for researchers and industrialists to further explore and develop sustainable and eco-friendly materials.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":"56 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142328701","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 : 2024-09-24DOI: 10.1177/10567895241279842
A Goumghar, K Azouaoui, M Assarar, W Zouari, S Mouhoubi, R Ayad, A El Mahi
The aim of this study is to investigate the fatigue behaviour of hybrid flax-glass/epoxy composites under repeated impact loading subsequent to water ageing. Different plates of these composite materials were fabricated using the vacuum infusion technique. Five stacking sequences were considered: [F8], [G/F3]S, [G2/F2]S, [G3/F]S, and [G8], where F and G stand for flax/epoxy and glass/epoxy plies, respectively. Water ageing was conducted by immersing the composite specimens in tap water at room temperature for various durations, and until saturation was reached. Fatigue impact tests were carried out using three impact energies: 3, 4, and 5 J. An advanced high-resolution camera was used to monitor the evolution of damage mechanisms occurring on the non-impacted surfaces, while a laser thermometer was considered to track the temperature variations within each composite specimen. The obtained results show that flax-glass hybridization reduces the mass of absorbed water in flax/epoxy composite by up to 70%. Furthermore, there is a more pronounced decrease in longitudinal modulus and maximum stress in aged composites, with reductions of up to 70% compared to unaged ones. Additionally, visible damage occurs even at low energy levels, manifesting from the initial impacts in both aged and unaged composite laminates. Moreover, a correlation between the number of impacts to failure and the cumulative energy is revealed. Ultimately, water aging reduces the strength of the studied composite laminates and their resistance to impact fatigue. Furthermore, the hybrid laminates with high proportion of flax layers are particularly susceptible to water ageing effects.
本研究的目的是调查亚麻-玻璃-环氧混合复合材料在水老化后反复冲击加载下的疲劳行为。采用真空灌注技术制造了这些复合材料的不同板材。考虑了五种堆叠序列：[F8]、[G/F3]S、[G2/F2]S、[G3/F]S 和 [G8]，其中 F 和 G 分别代表亚麻/环氧层和玻璃/环氧层。水老化是将复合材料试样浸泡在室温下的自来水中，浸泡时间长短不一，直至达到饱和状态。疲劳冲击试验采用三种冲击能量进行：先进的高分辨率照相机用于监控非撞击表面的损伤机制演变，而激光温度计则用于跟踪每个复合材料试样内部的温度变化。研究结果表明，亚麻-玻璃杂化使亚麻/环氧复合材料的吸水率降低了 70%。此外，在老化的复合材料中，纵向模量和最大应力的下降更为明显，与未老化的复合材料相比，降幅高达 70%。此外，即使在低能量水平下，老化和未老化的复合材料层压板也会从最初的冲击开始出现明显的损坏。此外，还发现了冲击到破坏的次数与累积能量之间的相关性。最终，水老化降低了所研究的复合材料层压板的强度及其抗冲击疲劳的能力。此外，亚麻层比例较高的混合层压板尤其容易受到水老化效应的影响。
{"title":"Damage investigation of hybrid flax-glass/epoxy composites subjected to impact fatigue under water ageing","authors":"A Goumghar, K Azouaoui, M Assarar, W Zouari, S Mouhoubi, R Ayad, A El Mahi","doi":"10.1177/10567895241279842","DOIUrl":"https://doi.org/10.1177/10567895241279842","url":null,"abstract":"The aim of this study is to investigate the fatigue behaviour of hybrid flax-glass/epoxy composites under repeated impact loading subsequent to water ageing. Different plates of these composite materials were fabricated using the vacuum infusion technique. Five stacking sequences were considered: [F<jats:sub>8</jats:sub>], [G/F<jats:sub>3</jats:sub>]<jats:sub>S</jats:sub>, [G<jats:sub>2</jats:sub>/F<jats:sub>2</jats:sub>]<jats:sub>S</jats:sub>, [G<jats:sub>3</jats:sub>/F]<jats:sub>S</jats:sub>, and [G<jats:sub>8</jats:sub>], where F and G stand for flax/epoxy and glass/epoxy plies, respectively. Water ageing was conducted by immersing the composite specimens in tap water at room temperature for various durations, and until saturation was reached. Fatigue impact tests were carried out using three impact energies: 3, 4, and 5 J. An advanced high-resolution camera was used to monitor the evolution of damage mechanisms occurring on the non-impacted surfaces, while a laser thermometer was considered to track the temperature variations within each composite specimen. The obtained results show that flax-glass hybridization reduces the mass of absorbed water in flax/epoxy composite by up to 70%. Furthermore, there is a more pronounced decrease in longitudinal modulus and maximum stress in aged composites, with reductions of up to 70% compared to unaged ones. Additionally, visible damage occurs even at low energy levels, manifesting from the initial impacts in both aged and unaged composite laminates. Moreover, a correlation between the number of impacts to failure and the cumulative energy is revealed. Ultimately, water aging reduces the strength of the studied composite laminates and their resistance to impact fatigue. Furthermore, the hybrid laminates with high proportion of flax layers are particularly susceptible to water ageing effects.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":"2 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142317537","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 : 2024-09-24DOI: 10.1177/10567895241280788
Lorenzo Pagliari, Franco Concli
Most of real-world structural components that undergo cyclic loading feature multiaxial fatigue. When the cyclic loading involves also significant plastic deformation, multiaxial low-cycle fatigue takes place. Applications where multiaxial low-cycle fatigue can be observed very often involve metal components. To predict their lives multiple criteria and models have been proposed, but their development has not followed a regular path. Multiple reviews are available in literature. However, many of them are outdated, they often employ different classification methods to categorize available criteria, many focus on specific families of criteria, and others do not include sufficient theoretical background. Moreover, none of the available reviews is based on a systematic literature search method. As a result, approaching the topic can result arduous and chaotic, especially for first timers. This work aims at providing a clear, comprehensive, and definitive review of available criteria for multiaxial low-cycle fatigue. First, the basic theoretical background is explained. Secondly, a systematic approach is described and employed to identify all major currently available criteria. Then, they are classified and commentary about different classification styles that can be found in literature is added. Eventually they are described, together with their latest proposed variations. In this way this review can be employed as a guiding reference, especially for engineers approaching the topic for the first time.
{"title":"A review of multiaxial low-cycle fatigue criteria for life prediction of metals","authors":"Lorenzo Pagliari, Franco Concli","doi":"10.1177/10567895241280788","DOIUrl":"https://doi.org/10.1177/10567895241280788","url":null,"abstract":"Most of real-world structural components that undergo cyclic loading feature multiaxial fatigue. When the cyclic loading involves also significant plastic deformation, multiaxial low-cycle fatigue takes place. Applications where multiaxial low-cycle fatigue can be observed very often involve metal components. To predict their lives multiple criteria and models have been proposed, but their development has not followed a regular path. Multiple reviews are available in literature. However, many of them are outdated, they often employ different classification methods to categorize available criteria, many focus on specific families of criteria, and others do not include sufficient theoretical background. Moreover, none of the available reviews is based on a systematic literature search method. As a result, approaching the topic can result arduous and chaotic, especially for first timers. This work aims at providing a clear, comprehensive, and definitive review of available criteria for multiaxial low-cycle fatigue. First, the basic theoretical background is explained. Secondly, a systematic approach is described and employed to identify all major currently available criteria. Then, they are classified and commentary about different classification styles that can be found in literature is added. Eventually they are described, together with their latest proposed variations. In this way this review can be employed as a guiding reference, especially for engineers approaching the topic for the first time.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":"216 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142317545","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 : 2024-09-18DOI: 10.1177/10567895241279845
Xikun Wu, Geoffrey Ginoux, Joseph Paux, Samir Allaoui
Additive manufacturing (AM) of continuous yarn-reinforced biobased composites presents multi-functional properties and low environmental impact of this technology. Few studies focused on the mechanical damage mechanisms of continuous biobased composites obtained by AM processes, while it is a topic of high interest for the mastery of mechanical behaviors and optimization of the materials for high requirement applications. This study aims to assess the damage and fracture modes of continuous flax yarn-reinforced PLA manufactured by AM, with different yarn orientations. The additively manufactured biobased composites were characterized by tensile test, 3D microscopy and micro-tomography to link the process-structure-properties relationships regarding the damage and fracture modes. The results showed that the 0° manufactured composite had a significant enhancement of tensile properties compared to other configurations. The damage mechanism presented fiber rupture with polymer transverse cracks at 0°, while the 45° and 90°-oriented composites showed premature fiber/matrix interface debonding. This study aims to find the relationship between damage mechanisms, deposition strategy, and anisotropy of the additively manufactured long vegetal fibers-reinforced biobased composite materials. The results bring a new understanding of the anisotropy and defects in printed composite materials regarding their mechanical behaviors during damage.
连续纱线增强生物基复合材料的快速成型（AM）技术具有多功能特性和低环境影响的特点。很少有研究关注通过 AM 工艺获得的连续生物基复合材料的机械损伤机理，而这对于掌握高要求应用领域的机械行为和优化材料是一个非常有意义的课题。本研究旨在评估 AM 制造的不同纱线取向的连续亚麻纱线增强聚乳酸的损伤和断裂模式。通过拉伸试验、三维显微镜和显微层析成像技术对添加剂制造的生物基复合材料进行表征，以联系有关损伤和断裂模式的工艺-结构-性能关系。结果表明，与其他结构相比，0°制造的复合材料的拉伸性能显著提高。损伤机制表现为 0° 方向的纤维断裂和聚合物横向裂纹，而 45° 和 90° 方向的复合材料则表现为过早的纤维/基质界面脱粘。本研究旨在探究加成制造的长植物纤维增强生物基复合材料的损伤机制、沉积策略和各向异性之间的关系。研究结果使人们对印刷复合材料的各向异性和缺陷在损坏过程中的力学行为有了新的认识。
{"title":"Damage and fracture studies of continuous flax fiber-reinforced composites 3D printed by in-nozzle impregnation additive manufacturing","authors":"Xikun Wu, Geoffrey Ginoux, Joseph Paux, Samir Allaoui","doi":"10.1177/10567895241279845","DOIUrl":"https://doi.org/10.1177/10567895241279845","url":null,"abstract":"Additive manufacturing (AM) of continuous yarn-reinforced biobased composites presents multi-functional properties and low environmental impact of this technology. Few studies focused on the mechanical damage mechanisms of continuous biobased composites obtained by AM processes, while it is a topic of high interest for the mastery of mechanical behaviors and optimization of the materials for high requirement applications. This study aims to assess the damage and fracture modes of continuous flax yarn-reinforced PLA manufactured by AM, with different yarn orientations. The additively manufactured biobased composites were characterized by tensile test, 3D microscopy and micro-tomography to link the process-structure-properties relationships regarding the damage and fracture modes. The results showed that the 0° manufactured composite had a significant enhancement of tensile properties compared to other configurations. The damage mechanism presented fiber rupture with polymer transverse cracks at 0°, while the 45° and 90°-oriented composites showed premature fiber/matrix interface debonding. This study aims to find the relationship between damage mechanisms, deposition strategy, and anisotropy of the additively manufactured long vegetal fibers-reinforced biobased composite materials. The results bring a new understanding of the anisotropy and defects in printed composite materials regarding their mechanical behaviors during damage.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":"50 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142245630","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 : 2024-09-14DOI: 10.1177/10567895241277681
Qiuxin Gu, Qiang Zhang, Wanli Dai, Xiaowei Quan, Sizhe Ye, Tao Li
The shear constitutive model of rock joints is of great significance to the stability analysis in rock engineering, and it is closely related to the normal stress ([Formula: see text]) and joint roughness coefficient ( JRC). However, the existing investigations seldom consider the influences of [Formula: see text] and JRC simultaneously. Therefore, a novel damage constitutive model considering the [Formula: see text] and JRC is developed in this work. In the presented model, it is assumed that the rock materials are composed of damaged and undamaged microunits, and the damage evolution law of the microunits conforms to the Weibull distribution in the shear process. Based on the proposed assumption, the constitutive relationship between shear stress and shear displacement is deduced. The evolutions of the mechanical parameters and damage variable versus [Formula: see text] and JRC are analyzed in detail. The proposed damage model that involves [Formula: see text] and JRC is verified by comparing theoretical values with the laboratory results. The results show that the damage constitutive model is in good agreement with the test results. Additionally, the influences of [Formula: see text] and JRC on the shear stress-displacement curves are studied. This work can provide a valuable theoretical method for analyzing the shear mechanical characteristics and damage evolution laws of rock joints.
{"title":"A novel statistical damage constitutive model of rock joints considering normal stress and joint roughness","authors":"Qiuxin Gu, Qiang Zhang, Wanli Dai, Xiaowei Quan, Sizhe Ye, Tao Li","doi":"10.1177/10567895241277681","DOIUrl":"https://doi.org/10.1177/10567895241277681","url":null,"abstract":"The shear constitutive model of rock joints is of great significance to the stability analysis in rock engineering, and it is closely related to the normal stress ([Formula: see text]) and joint roughness coefficient ( JRC). However, the existing investigations seldom consider the influences of [Formula: see text] and JRC simultaneously. Therefore, a novel damage constitutive model considering the [Formula: see text] and JRC is developed in this work. In the presented model, it is assumed that the rock materials are composed of damaged and undamaged microunits, and the damage evolution law of the microunits conforms to the Weibull distribution in the shear process. Based on the proposed assumption, the constitutive relationship between shear stress and shear displacement is deduced. The evolutions of the mechanical parameters and damage variable versus [Formula: see text] and JRC are analyzed in detail. The proposed damage model that involves [Formula: see text] and JRC is verified by comparing theoretical values with the laboratory results. The results show that the damage constitutive model is in good agreement with the test results. Additionally, the influences of [Formula: see text] and JRC on the shear stress-displacement curves are studied. This work can provide a valuable theoretical method for analyzing the shear mechanical characteristics and damage evolution laws of rock joints.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":"327 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142233310","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 : 2024-09-14DOI: 10.1177/10567895241277951
Mykola Bobyr, Vadim Silberchmidt, Viktor Koval
A low-cycle fatigue (LCF) analysis is one of the main design stages for highly loaded structural elements used in various applications. For this analysis, it is necessary to determine the values of local stresses and deformations, taking into account both elastic and plastic regions in the zones of stress concentration. This study presents and assesses the engineering methods used for prediction of low-cycle fatigue in structural elements. For zones of stress (strain) concentration, the Neuber-Makhutov method for LCF, taking into account the type of material stress-strain diagrams, is employed. The concept of distributed damage, based on the main ideas of the continuum damage mechanics of Kachanov-Rabotnov, was used. An approach employing the damage parameter for assessment of damage accumulation in LCF in highly loaded areas of structural elements is presented.
{"title":"Effort of damage parameter in assessment of low cycle fatigue","authors":"Mykola Bobyr, Vadim Silberchmidt, Viktor Koval","doi":"10.1177/10567895241277951","DOIUrl":"https://doi.org/10.1177/10567895241277951","url":null,"abstract":"A low-cycle fatigue (LCF) analysis is one of the main design stages for highly loaded structural elements used in various applications. For this analysis, it is necessary to determine the values of local stresses and deformations, taking into account both elastic and plastic regions in the zones of stress concentration. This study presents and assesses the engineering methods used for prediction of low-cycle fatigue in structural elements. For zones of stress (strain) concentration, the Neuber-Makhutov method for LCF, taking into account the type of material stress-strain diagrams, is employed. The concept of distributed damage, based on the main ideas of the continuum damage mechanics of Kachanov-Rabotnov, was used. An approach employing the damage parameter for assessment of damage accumulation in LCF in highly loaded areas of structural elements is presented.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":"62 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142233277","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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