Pub Date : 2024-09-06DOI: 10.1177/10567895241276444
M Dastjerdi, F Haji Aboutalebi, MS Sadeghi Nezhad
Damage measurement of materials is a crucial challenge for researchers and engineers in manufacturing industries. In this study, based on the image processing technique, a developed approach for determining the Lemaitre’s ductile damage parameter by the direct measurement method is proposed. For this purpose, first, the micrographs pictures are provided by a scanning electron microscope to attain the damage evolution behavior of St37 steel. Then, prediction results of the suggested method and the Lemaitre’s direct approach as well as the microhardness technique and also a lately published numerical method in damage propagation, crack initiation, and ductile fracture of a few tensile samples are compared with the corresponding experimental tests. The comparison reveals the higher efficiency and accuracy of the current approach. Therefore, it is concluded that the new presented method is a reliable approach to achieve the Lemaitre’s ductile damage parameter and predict the damage evolution behavior of ductile materials.
{"title":"An enhanced direct method for ductile damage measurement","authors":"M Dastjerdi, F Haji Aboutalebi, MS Sadeghi Nezhad","doi":"10.1177/10567895241276444","DOIUrl":"https://doi.org/10.1177/10567895241276444","url":null,"abstract":"Damage measurement of materials is a crucial challenge for researchers and engineers in manufacturing industries. In this study, based on the image processing technique, a developed approach for determining the Lemaitre’s ductile damage parameter by the direct measurement method is proposed. For this purpose, first, the micrographs pictures are provided by a scanning electron microscope to attain the damage evolution behavior of St37 steel. Then, prediction results of the suggested method and the Lemaitre’s direct approach as well as the microhardness technique and also a lately published numerical method in damage propagation, crack initiation, and ductile fracture of a few tensile samples are compared with the corresponding experimental tests. The comparison reveals the higher efficiency and accuracy of the current approach. Therefore, it is concluded that the new presented method is a reliable approach to achieve the Lemaitre’s ductile damage parameter and predict the damage evolution behavior of ductile materials.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":"9 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142144331","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}
Investigating the brittleness characteristics and damage evolution of deep rock masses under hydromechanical coupling has important significance. The variations in mechanical properties and brittleness characteristics of sandstone under different confining pressures and pore pressures were studied. Based on the stress threshold evolution and energy conversion analysis of the full stress-strain behavior characteristics of the rock, the new brittleness evaluation indexes were proposed, which effectively described the rock brittle failure mode and verified the reliability and applicability of the brittleness index. Additionally, from the perspective of rock pore micro-elements and the growth of matrix particle defects, the strain statistical damage theory was introduced to establish a rock statistical damage evolution model capable of accounting for the influence of pore pressure, thereby effectively capturing the nonlinear soft hardening of porous rocks under hydraulic coupling conditions. The correlation between rock brittleness and rock soft and hardening characteristics was reasonably expressed by constructing a new brittleness evaluation index, discovered from the relationship between rock damage parameters and brittleness characteristics. Eventually, based on the proposed nonlinear expression and statistical damage evolution model, the development trend of sandstone lateral strain is predicted well. The theoretical validation has good consistency with the experimental data and illustrates the rationality of the model.
{"title":"Brittleness evaluation and damage evolution of sandstone under hydromechanical coupling","authors":"Kuan Zhang, Wei Wang, Yajun Cao, Shifan Liu, Xuelei Duan","doi":"10.1177/10567895241277224","DOIUrl":"https://doi.org/10.1177/10567895241277224","url":null,"abstract":"Investigating the brittleness characteristics and damage evolution of deep rock masses under hydromechanical coupling has important significance. The variations in mechanical properties and brittleness characteristics of sandstone under different confining pressures and pore pressures were studied. Based on the stress threshold evolution and energy conversion analysis of the full stress-strain behavior characteristics of the rock, the new brittleness evaluation indexes were proposed, which effectively described the rock brittle failure mode and verified the reliability and applicability of the brittleness index. Additionally, from the perspective of rock pore micro-elements and the growth of matrix particle defects, the strain statistical damage theory was introduced to establish a rock statistical damage evolution model capable of accounting for the influence of pore pressure, thereby effectively capturing the nonlinear soft hardening of porous rocks under hydraulic coupling conditions. The correlation between rock brittleness and rock soft and hardening characteristics was reasonably expressed by constructing a new brittleness evaluation index, discovered from the relationship between rock damage parameters and brittleness characteristics. Eventually, based on the proposed nonlinear expression and statistical damage evolution model, the development trend of sandstone lateral strain is predicted well. The theoretical validation has good consistency with the experimental data and illustrates the rationality of the model.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":"381 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142138194","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}
The mechanical behavior under static and fatigue loading induced by mechanical forces is examined in this article through the utilization of a non-destructive methodology. However, it is worth noting that the dynamics of elastic waves become notably more intricate when dealing with composite materials. In order to provide a comprehensive description of the green flax/epoxy system, a crucial component of this study involves the computation of guided wave dispersion curves within the test samples. By evaluating the longitudinal and shear modulus under varying stress conditions, the propagation of high-frequency ultrasonic waves, which serves as a dynamic mechanical deformation, can be leveraged to facilitate the comparison of both mechanical and ultrasonic data. The significant changes occurring during the aging process are closely associated with variations in velocity throughout the loading period. The wavelet transformation of all acquired ultrasonic echoes yields the experimental transfer function, thereby enhancing our understanding of the subject matter.
{"title":"Behavior monitoring of flax fiber reinforced composites by guided waves","authors":"Driss Hana, Beyaoui Moez, Kesentini Zeineb, El Mahi Abderrahim, Bentahar Mourad, Haddar Mohamed, Deba Datta Mandal","doi":"10.1177/10567895241275365","DOIUrl":"https://doi.org/10.1177/10567895241275365","url":null,"abstract":"The mechanical behavior under static and fatigue loading induced by mechanical forces is examined in this article through the utilization of a non-destructive methodology. However, it is worth noting that the dynamics of elastic waves become notably more intricate when dealing with composite materials. In order to provide a comprehensive description of the green flax/epoxy system, a crucial component of this study involves the computation of guided wave dispersion curves within the test samples. By evaluating the longitudinal and shear modulus under varying stress conditions, the propagation of high-frequency ultrasonic waves, which serves as a dynamic mechanical deformation, can be leveraged to facilitate the comparison of both mechanical and ultrasonic data. The significant changes occurring during the aging process are closely associated with variations in velocity throughout the loading period. The wavelet transformation of all acquired ultrasonic echoes yields the experimental transfer function, thereby enhancing our understanding of the subject matter.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":"7 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142101002","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}
The vast changes in temperature are what produce thermal fatigue damage to concrete. In this study, concrete specimens in three different categories—C20, C40, and C60—are tested for thermal fatigue at temperatures ranging from 10°C to 80°C in an atmosphere with constant relative humidity. Utilizing ultrasonic nondestructive testing, the elastic modulus of concrete is determined. After thermal cycling, the mass reduction and appearance of samples are also recorded. The results demonstrate that the degrading effects of thermal fatigue clearly influence concrete. As the thermal cycle lengthens, the elastic modulus of concrete rapidly decreases, and C60 concrete experiences a greater reduction in elastic modulus than C20 concrete. With thermal cycles, the damage factor increases and the ultrasonic wave velocity steadily decreases, suggesting a propagation of the concrete’s interior microcracks. Additionally, the micromechanical thermal fatigue model is developed based on the experimental results. The ability to simulate and describe the physical behavior of concrete under thermal fatigue stress on the microscale is validated by the proposed micromechanical damage model.
{"title":"Experimental investigations and micromechanical thermal fatigue models of concrete","authors":"Haiyou Peng, Qiang Xie, Chong Wang, Shuai Zhou, J Woody Ju","doi":"10.1177/10567895241278666","DOIUrl":"https://doi.org/10.1177/10567895241278666","url":null,"abstract":"The vast changes in temperature are what produce thermal fatigue damage to concrete. In this study, concrete specimens in three different categories—C20, C40, and C60—are tested for thermal fatigue at temperatures ranging from 10°C to 80°C in an atmosphere with constant relative humidity. Utilizing ultrasonic nondestructive testing, the elastic modulus of concrete is determined. After thermal cycling, the mass reduction and appearance of samples are also recorded. The results demonstrate that the degrading effects of thermal fatigue clearly influence concrete. As the thermal cycle lengthens, the elastic modulus of concrete rapidly decreases, and C60 concrete experiences a greater reduction in elastic modulus than C20 concrete. With thermal cycles, the damage factor increases and the ultrasonic wave velocity steadily decreases, suggesting a propagation of the concrete’s interior microcracks. Additionally, the micromechanical thermal fatigue model is developed based on the experimental results. The ability to simulate and describe the physical behavior of concrete under thermal fatigue stress on the microscale is validated by the proposed micromechanical damage model.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":"146 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142101001","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 : 2024-08-22DOI: 10.1177/10567895241277217
Cheng Hongming, Yang Xiaobin, Lu Jie, Dong Chuanlong, Lan Yongqing
The nonlinearity of the constitutive relation for rocks becomes more prominent with a more complex physical-mechanical environment and mechanical behavior. The accurate establishment of the constitutive relation affects the determination of rock deformation and damage state from physical features. In this study, a novel statistical damage constitutive model for rocks is proposed based on quantified energy conversion. The novelty of the model is that the nature of rock damage before and after damage stress is considered. In the constitutive model, the evolution characteristics of energy conversion show a five-stage evolution with a ‘spoon’ form and correspond to the rock deformation and damage process, which can be fitted with the modified GaussAmp function; the damage variable is deduced by the Weibull distribution with energy conversion as the distribution variable, which presents a monotonic decrease caused by initial defects before the σcd and shows a ‘S’ shape caused by nascent cracks after the σcd. Furthermore, triaxial test data of three types of rocks under different confining pressures were used to verify the proposed model, and the results were in good agreement with the test data in most cases. The characteristics of the crack closure stage, peak stress, residual strength, and stress drop process are controlled by the model parameters, which can be determined using experimental data. As these parameters definitely have a physical meaning and a relation to the confining pressure, the proposed model has the potential to be used in rock engineering.
{"title":"Statistical damage constitutive model based on energy conversion for rocks","authors":"Cheng Hongming, Yang Xiaobin, Lu Jie, Dong Chuanlong, Lan Yongqing","doi":"10.1177/10567895241277217","DOIUrl":"https://doi.org/10.1177/10567895241277217","url":null,"abstract":"The nonlinearity of the constitutive relation for rocks becomes more prominent with a more complex physical-mechanical environment and mechanical behavior. The accurate establishment of the constitutive relation affects the determination of rock deformation and damage state from physical features. In this study, a novel statistical damage constitutive model for rocks is proposed based on quantified energy conversion. The novelty of the model is that the nature of rock damage before and after damage stress is considered. In the constitutive model, the evolution characteristics of energy conversion show a five-stage evolution with a ‘spoon’ form and correspond to the rock deformation and damage process, which can be fitted with the modified GaussAmp function; the damage variable is deduced by the Weibull distribution with energy conversion as the distribution variable, which presents a monotonic decrease caused by initial defects before the σ<jats:sub>cd</jats:sub> and shows a ‘S’ shape caused by nascent cracks after the σ<jats:sub>cd</jats:sub>. Furthermore, triaxial test data of three types of rocks under different confining pressures were used to verify the proposed model, and the results were in good agreement with the test data in most cases. The characteristics of the crack closure stage, peak stress, residual strength, and stress drop process are controlled by the model parameters, which can be determined using experimental data. As these parameters definitely have a physical meaning and a relation to the confining pressure, the proposed model has the potential to be used in rock engineering.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":"145 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142042493","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 : 2024-08-22DOI: 10.1177/10567895241275380
Xunjian Hu, Dongdong Ma, Ni Xie, Qizhi Zhu, Haibo Hu, Xiaonan Gong
Enhancing our understanding of the damage evolution in pre-heated rock is essential for safer design practices. Accordingly, a mechanical damage variable that accurately depicts the initial damage recovery process was proposed. Subsequently, a damage constitutive model is developed based on the generalized equivalent strain principle, enabling the identification of the initial nonlinear characteristics exhibited in the stress-strain curve. By integrating the above constitutive model with a statistical damage model that considers the residual strength based on the Weibull distribution, a comprehensive piecewise damage constitutive model specifically designed for pre-heated rocks was derived. The model consists of eight parameters, which can be directly determined through experimental results or readily obtained by fitting of the stress-strain data. A comparison of experimental data from multiple pre-heated rock types subjected to uniaxial compression is performed to validate the proposed model, revealing a strong agreement between the theoretical and experimental results. The comparison results demonstrate that the proposed model effectively captures the nonlinearity of the stress-strain curve throughout various stages, including the initial compaction, linear elastic, and strain-hardening stages before reaching the peak stress, as well as the subsequent strain-softening and residual stages. Furthermore, the proposed damage constitutive model elucidates the influence of temperature on crucial factors such as the elastic modulus, peak stress, residual strength, and stress-strain curve of pre-heated rocks, thereby enhancing its applicability in the design of deep underground rock projects.
{"title":"An improved damage constitutive model for pre-heated rocks under uniaxial compression considering the initial compaction effect and residual strength","authors":"Xunjian Hu, Dongdong Ma, Ni Xie, Qizhi Zhu, Haibo Hu, Xiaonan Gong","doi":"10.1177/10567895241275380","DOIUrl":"https://doi.org/10.1177/10567895241275380","url":null,"abstract":"Enhancing our understanding of the damage evolution in pre-heated rock is essential for safer design practices. Accordingly, a mechanical damage variable that accurately depicts the initial damage recovery process was proposed. Subsequently, a damage constitutive model is developed based on the generalized equivalent strain principle, enabling the identification of the initial nonlinear characteristics exhibited in the stress-strain curve. By integrating the above constitutive model with a statistical damage model that considers the residual strength based on the Weibull distribution, a comprehensive piecewise damage constitutive model specifically designed for pre-heated rocks was derived. The model consists of eight parameters, which can be directly determined through experimental results or readily obtained by fitting of the stress-strain data. A comparison of experimental data from multiple pre-heated rock types subjected to uniaxial compression is performed to validate the proposed model, revealing a strong agreement between the theoretical and experimental results. The comparison results demonstrate that the proposed model effectively captures the nonlinearity of the stress-strain curve throughout various stages, including the initial compaction, linear elastic, and strain-hardening stages before reaching the peak stress, as well as the subsequent strain-softening and residual stages. Furthermore, the proposed damage constitutive model elucidates the influence of temperature on crucial factors such as the elastic modulus, peak stress, residual strength, and stress-strain curve of pre-heated rocks, thereby enhancing its applicability in the design of deep underground rock projects.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":"4 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142042484","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}
Damage precursors during hydraulic fracturing in shale gas reservoirs may be better understood if the deformation, failure, and acoustic emission (AE) characteristics under cyclic loading are known. Therefore, the purpose of this paper is to investigate the quantitative damage based on the Felicity effect under constant stress lower limit uniaxial cyclic loading-unloading rates (0.5, 1.0, 1.5, 2.0, and 2.5 kN/s). Variations in the b-value and the spatiotemporal evolution of cumulative AE were also used to observe how shale fractures formed. The findings reveal that during the unloading stage, there are many cumulative AE events when the stress level is low (≤1.50 kN/s) but that this number drops significantly when the stress level increases above (>2.0 kN/s). The AE amplitude, AE counts, and cumulative AE energy of each cycle in a loading-unloading test show an increasing trend, but the rate increases in the last cycle. During the whole process of loading and unloading, the Kaiser effects were present in the 3rd cycle at stress levels (≤1.5 kN/s). Still, the Felicity effect appeared in the 2nd and 1st cycles during 2.0 and 2.5 kN/s cyclic loading. The Kaiser effect occurs in the linear elastic stage, while the Felicity effect occurs in the crack initiation and crack damage stage. Furthermore, the Felicity ratio (FR) variations during shale deformation and failure can be divided into four phases: (Phase I = 1.01 ≥ FR > 0.89), (Phase II = 0.89 ≥ FR > 0.48), (Phase III = 0.48 ≥ FR > 0.23), and (Phase IV = FR ≤ 0.23). The b-value is relatively higher under the loading rate below (≤1.50 kN/s), indicating an increase in the number of small AE events. In contrast, the fact that the b-value is relatively smaller under the loading rate above (>2.0 kN/s) indicates that, the number of large AE events increases the number of cracks and fractures. These findings provide important design references for damaged precursors during hydraulic fracturing in shale gas reservoirs.
{"title":"Evolution of the damage precursor based on the felicity effect in shale","authors":"PK Gautam, Rishabh Dwivedi, Peeyush Garg, Dipaloke Majumder, Siddhartha Agarwal, Maurice McSaveney, TN Singh","doi":"10.1177/10567895241253727","DOIUrl":"https://doi.org/10.1177/10567895241253727","url":null,"abstract":"Damage precursors during hydraulic fracturing in shale gas reservoirs may be better understood if the deformation, failure, and acoustic emission (AE) characteristics under cyclic loading are known. Therefore, the purpose of this paper is to investigate the quantitative damage based on the Felicity effect under constant stress lower limit uniaxial cyclic loading-unloading rates (0.5, 1.0, 1.5, 2.0, and 2.5 kN/s). Variations in the b-value and the spatiotemporal evolution of cumulative AE were also used to observe how shale fractures formed. The findings reveal that during the unloading stage, there are many cumulative AE events when the stress level is low (≤1.50 kN/s) but that this number drops significantly when the stress level increases above (>2.0 kN/s). The AE amplitude, AE counts, and cumulative AE energy of each cycle in a loading-unloading test show an increasing trend, but the rate increases in the last cycle. During the whole process of loading and unloading, the Kaiser effects were present in the 3rd cycle at stress levels (≤1.5 kN/s). Still, the Felicity effect appeared in the 2nd and 1st cycles during 2.0 and 2.5 kN/s cyclic loading. The Kaiser effect occurs in the linear elastic stage, while the Felicity effect occurs in the crack initiation and crack damage stage. Furthermore, the Felicity ratio (FR) variations during shale deformation and failure can be divided into four phases: (Phase I = 1.01 ≥ FR > 0.89), (Phase II = 0.89 ≥ FR > 0.48), (Phase III = 0.48 ≥ FR > 0.23), and (Phase IV = FR ≤ 0.23). The b-value is relatively higher under the loading rate below (≤1.50 kN/s), indicating an increase in the number of small AE events. In contrast, the fact that the b-value is relatively smaller under the loading rate above (>2.0 kN/s) indicates that, the number of large AE events increases the number of cracks and fractures. These findings provide important design references for damaged precursors during hydraulic fracturing in shale gas reservoirs.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":"23 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141096575","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 : 2024-05-23DOI: 10.1177/10567895241245956
Kaihang Han, J Woody Ju, Xiangsheng Chen, Le-Yang Lv, Shuai Zhou, Gang Wei, Zhiguo Zhang, Hongzhi Cui
The research on the concrete structure built with self-healing materials brings inspiration to increase the safety and sustainability of underground structures in the whole life cycle. The utilization of microencapsulated healing agents in self-healing concrete has demonstrated efficacy in the repair of microcracks within concrete structures. Nevertheless, there exists a dearth of effective methodologies for assessing the impact of microcapsule parameters on the mechanical properties of self-healing concrete. This study introduces an innovative three-dimensional micromechanical model that can be utilized to analyze the micromechanical response of microencapsulated self-healing concrete under tensile loading conditions. The 3D micromechanical model is accomplished through the utilization of the elastic secant compliance tensor. Subsequently, a comprehensive examination is undertaken to analyze the progression of damage-healing in self-healing concrete incorporating microcapsules. Finally, a parametric investigation is conducted to elucidate the impact of the micro-parameters on the mechanical behavior of self-healing concrete. The present discovery holds significant implications for the development of microencapsulated self-healing concrete for underground structures, particularly in terms of establishing appropriate parameters.
{"title":"A 3D micromechanical model to predict the complete stress-strain relation of microencapsulated self-healing concrete","authors":"Kaihang Han, J Woody Ju, Xiangsheng Chen, Le-Yang Lv, Shuai Zhou, Gang Wei, Zhiguo Zhang, Hongzhi Cui","doi":"10.1177/10567895241245956","DOIUrl":"https://doi.org/10.1177/10567895241245956","url":null,"abstract":"The research on the concrete structure built with self-healing materials brings inspiration to increase the safety and sustainability of underground structures in the whole life cycle. The utilization of microencapsulated healing agents in self-healing concrete has demonstrated efficacy in the repair of microcracks within concrete structures. Nevertheless, there exists a dearth of effective methodologies for assessing the impact of microcapsule parameters on the mechanical properties of self-healing concrete. This study introduces an innovative three-dimensional micromechanical model that can be utilized to analyze the micromechanical response of microencapsulated self-healing concrete under tensile loading conditions. The 3D micromechanical model is accomplished through the utilization of the elastic secant compliance tensor. Subsequently, a comprehensive examination is undertaken to analyze the progression of damage-healing in self-healing concrete incorporating microcapsules. Finally, a parametric investigation is conducted to elucidate the impact of the micro-parameters on the mechanical behavior of self-healing concrete. The present discovery holds significant implications for the development of microencapsulated self-healing concrete for underground structures, particularly in terms of establishing appropriate parameters.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":"43 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141092003","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 : 2024-05-17DOI: 10.1177/10567895241253735
Di Wu, Laiwang Jing, Wei Jing, Shaochi Peng
This study aims to establish a strain instanton equation and damage factor evolution law for gypsum specimens by considering damping. First, damping energy is calculated based on the single-degree-of-freedom vibration model, and the instantaneous strain equation is obtained based on the stress balance equation. Second, the dissipation energy is divided into damping and damage energies, and a damage-factor correction algorithm is obtained. Third, cyclic loading and unloading tests were performed at different loading rates and stress amplitudes to verify the accuracy of the strain equation. Finally, the specimens’ magnitude curves and crack characteristics were monitored using moment–tensor acoustic emission simulations. The factors influencing the damping energy and strain equations, energy and damage evolution laws of the specimens, and damage patterns of the specimens at different loading rates were analysed. The results show that the instantaneous strain equation and the modified damage factor considering the damping effect can effectively reflect the deformation law and damage state of the specimens. In contrast, the damage to the specimens in the lower limit of the variable stress experiment was lower than that in the lower limit of the constant stress experiment. As the loading rate increases, the damage energy density of the specimen decreases, and the damage factor within a single cycle gradually decreases. As the loading rate increases, the number of crack events in the model increases significantly, size becomes more uniform, and sequentially exhibits dense and sparse distribution patterns, percentage of shear cracks decreases significantly, number of mixed cracks increases significantly, brittle behaviour of the specimen becomes obvious, and a complete damage state is attained known as the ‘crushed’ state. This study provides a theoretical reference for damage assessments of viscoelastic–plastic materials subjected to perturbing loads.
{"title":"Cyclic loading and unloading strain equations and damage evolution of gypsum specimens considering damping effects","authors":"Di Wu, Laiwang Jing, Wei Jing, Shaochi Peng","doi":"10.1177/10567895241253735","DOIUrl":"https://doi.org/10.1177/10567895241253735","url":null,"abstract":"This study aims to establish a strain instanton equation and damage factor evolution law for gypsum specimens by considering damping. First, damping energy is calculated based on the single-degree-of-freedom vibration model, and the instantaneous strain equation is obtained based on the stress balance equation. Second, the dissipation energy is divided into damping and damage energies, and a damage-factor correction algorithm is obtained. Third, cyclic loading and unloading tests were performed at different loading rates and stress amplitudes to verify the accuracy of the strain equation. Finally, the specimens’ magnitude curves and crack characteristics were monitored using moment–tensor acoustic emission simulations. The factors influencing the damping energy and strain equations, energy and damage evolution laws of the specimens, and damage patterns of the specimens at different loading rates were analysed. The results show that the instantaneous strain equation and the modified damage factor considering the damping effect can effectively reflect the deformation law and damage state of the specimens. In contrast, the damage to the specimens in the lower limit of the variable stress experiment was lower than that in the lower limit of the constant stress experiment. As the loading rate increases, the damage energy density of the specimen decreases, and the damage factor within a single cycle gradually decreases. As the loading rate increases, the number of crack events in the model increases significantly, size becomes more uniform, and sequentially exhibits dense and sparse distribution patterns, percentage of shear cracks decreases significantly, number of mixed cracks increases significantly, brittle behaviour of the specimen becomes obvious, and a complete damage state is attained known as the ‘crushed’ state. This study provides a theoretical reference for damage assessments of viscoelastic–plastic materials subjected to perturbing loads.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":"123 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140954299","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 : 2024-05-15DOI: 10.1177/10567895241245869
Yibo Yang, Li Zou, Xinyu Cao, Xinhua Yang, Yibo Sun
The Manson-Halford (M-H) nonlinear cumulative damage model is widely applied for fatigue life analysis problems under multi-level loading. In this model, the influence of loading sequence on the fatigue life can be better considerer, but the loading interaction effect is ignored. An improved whale optimization algorithm (IWOA) by integrating multiple strategies is proposed. The ability of global search and local exploitation is balanced and improved through nonlinear convergence factor, adaptive weighting factors and the Cauchy reverse learning strategies. In order to fully account for loading interaction effect, loading weighting factors are introduced to modify the M-H model, and the parameters are optimized through the global search properties of IWOA. The model is evaluated on multi-level loading fatigue experimental data from five metal materials and two aluminum alloy welded joints. The results suggest that the proposed IWOA has better optimization accuracy compared to the standard whale optimization algorithm (WOA). The proposed modified M-H model has better prediction performance compared to the four traditional cumulative damage models, which can be effectively applied to multi-level loading fatigue life analysis problems under actual working conditions. The proposed model is useful for the study of fatigue life evaluation methods.
{"title":"A modified Manson-Halford model based on improved WOA for fatigue life prediction under multi-level loading","authors":"Yibo Yang, Li Zou, Xinyu Cao, Xinhua Yang, Yibo Sun","doi":"10.1177/10567895241245869","DOIUrl":"https://doi.org/10.1177/10567895241245869","url":null,"abstract":"The Manson-Halford (M-H) nonlinear cumulative damage model is widely applied for fatigue life analysis problems under multi-level loading. In this model, the influence of loading sequence on the fatigue life can be better considerer, but the loading interaction effect is ignored. An improved whale optimization algorithm (IWOA) by integrating multiple strategies is proposed. The ability of global search and local exploitation is balanced and improved through nonlinear convergence factor, adaptive weighting factors and the Cauchy reverse learning strategies. In order to fully account for loading interaction effect, loading weighting factors are introduced to modify the M-H model, and the parameters are optimized through the global search properties of IWOA. The model is evaluated on multi-level loading fatigue experimental data from five metal materials and two aluminum alloy welded joints. The results suggest that the proposed IWOA has better optimization accuracy compared to the standard whale optimization algorithm (WOA). The proposed modified M-H model has better prediction performance compared to the four traditional cumulative damage models, which can be effectively applied to multi-level loading fatigue life analysis problems under actual working conditions. The proposed model is useful for the study of fatigue life evaluation methods.","PeriodicalId":13837,"journal":{"name":"International Journal of Damage Mechanics","volume":"21 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140949426","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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