The effect of cryogenic temperatures on the mechanical properties and fracture mechanism of SnAgCu−SnPb mixed solder joints was investigated.The results showed that the tensile strength of mixed solder joints first in...The effect of cryogenic temperatures on the mechanical properties and fracture mechanism of SnAgCu−SnPb mixed solder joints was investigated.The results showed that the tensile strength of mixed solder joints first increased with the increase of Pb content and reached its maximum at 22.46 wt.%Pb;subsequently,it decreased as Pb content increased.However,cryogenic temperatures improved the tensile strength of the solder joints.Both Pb content and cryogenic temperature caused the fracture mode of the mixed solder joints to change;however,temperature remained the main influencing factor.As the temperature fell from 298 to 123 K,the failure pattern in the solder joints transformed from ductile fracture to quasi-ductile fracture to quasi-brittle fracture and finally,to brittle fracture.展开更多
The results of a theoretical study on the influence of strength of interphase boundaries in metal-ceramic composite on macroscopical characteristics of composite response such as strength, deformation capacity, fractu...The results of a theoretical study on the influence of strength of interphase boundaries in metal-ceramic composite on macroscopical characteristics of composite response such as strength, deformation capacity, fracture energy and fracture pattern are presented. The study was conducted by means of computer-aided simulation by means of movable cellular automaton method taking account of a developed ＂mesoscopical＂ structural model of particle-reinforced composite. The strength of interphase boundaries is found to be a key structural factor determining not only the strength properties of metal-ceramic composite, but also the pattern and rate of fracture. The principles for achievement of the high-strength values of particle/binder interfaces in the metal-ceramic composition due to the formation of the wide transition zones （areas of variable chemical composition） at the interphase boundaries are discussed. Simulation results confirm that such transition zones provide a change in fracture mechanism and make the achievement of a high-strength and a high deformation capacity of metal-ceramic composite possible.展开更多
Semivariogram is applied to fracture data obtained from detailed scanlinesurveys of nine field sites in western New York, USA in order to investigate the spatial patterns ofnatural fractures. The length of the scanlin...Semivariogram is applied to fracture data obtained from detailed scanlinesurveys of nine field sites in western New York, USA in order to investigate the spatial patterns ofnatural fractures. The length of the scanline is up to 36 m. How both fracture spacing and fracturelength vary with distance is determined through semivariogram calculations. In this study, theauthors developed a FORTRAN program to resample the fracture data from the scanline survey. Bycalculating experimental semivariogram, the authors found five different types of spatial patternsthat can be described by linear, spherical, reversed spherical, polynomial I (for aO) models, of which the last three arc newly proposed in this study. Thewell-structured semivariograms of fracture spacing and length indicate that both the location of thefractures and the length distribution within their structure domains are not random. The results ofthis study also suggest that semivariograms can provide useful information in terms of spatialcorrelation distance for fracture location and fracture length. These semivariograms can also beutilized to design more efficient sampling schemes for further surveys. as well as to define thelimits of highly probable extrapolation of a structure domain.展开更多
sing the natural limestone samples taken from the field with dimension of 500 mm×500 mm×1 000 mm, the D-D (dilatancy-diffusion) seismogeny pattern was modeled under the condition of water injection, which ob...sing the natural limestone samples taken from the field with dimension of 500 mm×500 mm×1 000 mm, the D-D (dilatancy-diffusion) seismogeny pattern was modeled under the condition of water injection, which observes the time-space evolutionary features about the relative physics fields of the loaded samples from deformation, formation of microcracks to the occurrence of main rupture. The results of observed apparent resistivity show: ① The process of the deformation from microcrack to main rupture on the loaded rock sample could be characterized by the precursory spatial-temporal changes in the observation of apparent resistivity; ② The precursory temporal changes of observation in apparent resistivity could be divided into several stages, and its spatial distribution shows the difference in different parts of the rock sample; ③ Before the main rupture of the rock sample the obvious ″tendency anomaly′ and ′short-term anomaly″ were observed, and some of them could be likely considered as the ″impending earthquake ″anomaly precursor of apparent resistivity. The changes and distribution features of apparent resistivity show that they are intrinsically related to the dilatancy phenomenon of the loaded rock sample. Finally, this paper discusses the mechanism of resistivity change of loaded rock sample theoretically.展开更多
The microstructure,fracture mechanisms,deformation modes,and their correlation with the mechanical properties of Mg-Zn-Gd alloys were analyzed,considering the influence of Y and Nd additions.Increasing Y content and d...The microstructure,fracture mechanisms,deformation modes,and their correlation with the mechanical properties of Mg-Zn-Gd alloys were analyzed,considering the influence of Y and Nd additions.Increasing Y content and decreasing Nd content resulted in an increase in grain size from 17.2 to 29.2μm,and two types of LPSO phases,14 H and 18 R,formed in the alloy.The mechanical properties of the alloys were predominantly influenced by the LPSO phase,with the grain size effect being relatively minor.Based on this analysis,higher Y and lower Nd contents enhanced the tensile strength,yield strength,and elongation of the alloys,with additional improvements observed following solid solution treatment.Changes in Y and Nd content caused a shift in fracture patterns,transitioning from ductile fracture to brittle fracture and then to mixed fracture.Following solid solution treatment,the alloy progressively transitions from intergranular to a combination of ductile and deconvolutional fracture.The deformation modes observed at each stage are as follows:an increase in LPSO phases and twins activates pyramidal slip and suppresses prismatic slip.展开更多
Supercritical CO_(2)(SC-CO_(2)) fracturing, being a waterless fracturing technology, has garnered increasing attention in the shale oil reservoir exploitation industry. Recently, a novel pre-SC-CO_(2) hybrid fracturin...Supercritical CO_(2)(SC-CO_(2)) fracturing, being a waterless fracturing technology, has garnered increasing attention in the shale oil reservoir exploitation industry. Recently, a novel pre-SC-CO_(2) hybrid fracturing method has been proposed, which combines the advantages of SC-CO_(2) fracturing and hydraulic fracturing. However, the specific impacts of different pre-SC-CO_(2) injection conditions on the physical parameters, mechanical properties, and crack propagation behavior of shale reservoirs remain unclear. In this study, we utilize a newly developed “pre-SC-CO_(2) injection → water-based fracturing” integrated experimental device. Through experimentation under in-situ conditions, the impact of pre-SC-CO_(2) injection displacement and volume on the shale mineral composition, mechanical parameters, and fracture propagation behavior are investigated. The findings of the study demonstrate that the pre-injection SC-CO_(2) leads to a reduction in clay and carbonate mineral content, while increasing the quartz content. The correlation between quartz content and SC-CO_(2) injection volume is positive, while a negative correlation is observed with injection displacement. The elastic modulus and compressive strength exhibit a declining trend, while Poisson's ratio shows an increasing trend. The weakening of shale mechanics caused by pre-injection of SC-CO_(2) is positively correlated with the injection displacement and volume.Additionally, pre-injection of SC-CO_(2) enhances the plastic deformation behavior of shale, and its breakdown pressure is 16.6% lower than that of hydraulic fracturing. The breakdown pressure demonstrates a non-linear downward trend with the gradual increase of pre-SC-CO_(2) injection parameters.Unlike hydraulic fracturing, which typically generates primary fractures along the direction of the maximum principal stress, pre-SC-CO_(2) hybrid fracturing leads to a more complex fracture network. With increasing pre-SC-CO_(2) injection displacement, intersecting double Y-shaped complex fractures are formed along the vertical axis. On the other hand, increasing the injection rate generates secondary fractures along the direction of non-principal stress. The insights gained from this study are valuable for guiding the design of pre SC-CO_(2) hybrid fracturing in shale oil reservoirs.展开更多
The experimental study in this paper focuses on the effects of the layer orientation and sample shape on failure strength and fracture pattern of samples tested under Brazilian test conditions(i.e.diametrical loading ...The experimental study in this paper focuses on the effects of the layer orientation and sample shape on failure strength and fracture pattern of samples tested under Brazilian test conditions(i.e.diametrical loading of cylindrical discs)for one particular layered sandstone which is from Modave in the south of Belgium.The variations of the strength in combination with the failure patterns are examined as a function of the inclination angle between the layer plane and the loading direction.The experimental,results clearly show that the induced fracture patterns are a combination of tensile and/or shear fractures.In shape effect experiments the layer thickness and the number of layer boundaries are investigated.Different blocks of Modave sandstone are used to prepare samples.The layer thickness is different among the various blocks,but the layer thickness in each studied rock block can be considered to be constant;hence,the number of layer boundaries changes according to the sample diameter for samples of the same block.The experimental study shows that the layer thickness plays a more important role than the number of layer boundaries per sample.展开更多
A thorough understanding of the fracture characteristics can assist the decision-making process for surgery.This study aimed to characterize the femoral neck fractures among middle-aged patients and illustrated a biom...A thorough understanding of the fracture characteristics can assist the decision-making process for surgery.This study aimed to characterize the femoral neck fractures among middle-aged patients and illustrated a biomedical visualization method using a fracture mapping model and augmented reality.We collected plain radiography and computed tomography(CT)data from 156 adult patients with a femoral neck fracture.The descriptive study showed that Type I and Type II fractures accounted for 8(5%)and 64(41%)cases.In comparison,Type IV fractures accounted for 44(28%)and 40(25%)cases according to the Garden classification.Comminuted fractures and cortical defects were identified in 14.74%and 29.49%of the cases.A fracture mapping model was reconstructed based on the CT data and demonstrated the location and distribution of the major fracture lines surrounding the head-neck junction.We also illustrated the application of augmented reality technology to visualize and interact with the patient-specific fracture model and the fracture mapping model that facilitated education,training,and surgical planning.Future studies may consider mapping other biomechanical data,such as joint loading and stress distribution,and exploring artificial intelligence via deep reinforcement learning for computer-aided fracture reduction and procedure planning.展开更多
In the study, mechanical abuse tests mainly in the form of indentation were performed on the cylindrical cell, pouch cell, and prismatic cell. The mechanical force-displacement response, open circuit voltage(OCV), and...In the study, mechanical abuse tests mainly in the form of indentation were performed on the cylindrical cell, pouch cell, and prismatic cell. The mechanical force-displacement response, open circuit voltage(OCV), and temperature distribution were recorded and compared. In spherical head indentation tests of the pouch and prismatic cell and lateral indentation of the cylindrical cell, the peak force is strongly correlated with OCV drop and local temperature increase. However, in flat-end cylinder indentation tests, the internal mechanical damage is progressively developed, and the OCV drop and the temperature increase occur before the peak force. The fracture surfaces of the post-mortem samples were examined to investigate the correlation between fracture patterns and internal short circuit(ISC) behaviors(OCVand temperature distribution). Two distinct fracture patterns were observed that the in-plane fracture induced by biaxial stretching and inter-layers' fracture induced by shearing. A strong correlation is observed between the number of shear fractures and OCV drop. An increase in the number of inter-layers' fractures increases the rate of OCV drop. Additionally, the fracture patterns influence the ISC area and location,thereby affecting the heat generation and conduction as well as the temperature distribution.展开更多
基金The authors are grateful for the financial supports from the National Natural Science Foundation of China(No.51965044)the Aeronautical Science Foundation of China(No.20185456005).
文摘The effect of cryogenic temperatures on the mechanical properties and fracture mechanism of SnAgCu−SnPb mixed solder joints was investigated.The results showed that the tensile strength of mixed solder joints first increased with the increase of Pb content and reached its maximum at 22.46 wt.%Pb;subsequently,it decreased as Pb content increased.However,cryogenic temperatures improved the tensile strength of the solder joints.Both Pb content and cryogenic temperature caused the fracture mode of the mixed solder joints to change;however,temperature remained the main influencing factor.As the temperature fell from 298 to 123 K,the failure pattern in the solder joints transformed from ductile fracture to quasi-ductile fracture to quasi-brittle fracture and finally,to brittle fracture.
基金The investigation has been carried out within the SB RAS Program Ⅲ.20.2 for Basic Researchat partial financial support of the RFBR Grant No.11-08-12069-ofi-m-2011+1 种基金the Project No.5 of the Belarus NASSB RAS Program for Joint Basic Research
文摘The results of a theoretical study on the influence of strength of interphase boundaries in metal-ceramic composite on macroscopical characteristics of composite response such as strength, deformation capacity, fracture energy and fracture pattern are presented. The study was conducted by means of computer-aided simulation by means of movable cellular automaton method taking account of a developed ＂mesoscopical＂ structural model of particle-reinforced composite. The strength of interphase boundaries is found to be a key structural factor determining not only the strength properties of metal-ceramic composite, but also the pattern and rate of fracture. The principles for achievement of the high-strength values of particle/binder interfaces in the metal-ceramic composition due to the formation of the wide transition zones （areas of variable chemical composition） at the interphase boundaries are discussed. Simulation results confirm that such transition zones provide a change in fracture mechanism and make the achievement of a high-strength and a high deformation capacity of metal-ceramic composite possible.
文摘Semivariogram is applied to fracture data obtained from detailed scanlinesurveys of nine field sites in western New York, USA in order to investigate the spatial patterns ofnatural fractures. The length of the scanline is up to 36 m. How both fracture spacing and fracturelength vary with distance is determined through semivariogram calculations. In this study, theauthors developed a FORTRAN program to resample the fracture data from the scanline survey. Bycalculating experimental semivariogram, the authors found five different types of spatial patternsthat can be described by linear, spherical, reversed spherical, polynomial I (for aO) models, of which the last three arc newly proposed in this study. Thewell-structured semivariograms of fracture spacing and length indicate that both the location of thefractures and the length distribution within their structure domains are not random. The results ofthis study also suggest that semivariograms can provide useful information in terms of spatialcorrelation distance for fracture location and fracture length. These semivariograms can also beutilized to design more efficient sampling schemes for further surveys. as well as to define thelimits of highly probable extrapolation of a structure domain.
文摘sing the natural limestone samples taken from the field with dimension of 500 mm×500 mm×1 000 mm, the D-D (dilatancy-diffusion) seismogeny pattern was modeled under the condition of water injection, which observes the time-space evolutionary features about the relative physics fields of the loaded samples from deformation, formation of microcracks to the occurrence of main rupture. The results of observed apparent resistivity show: ① The process of the deformation from microcrack to main rupture on the loaded rock sample could be characterized by the precursory spatial-temporal changes in the observation of apparent resistivity; ② The precursory temporal changes of observation in apparent resistivity could be divided into several stages, and its spatial distribution shows the difference in different parts of the rock sample; ③ Before the main rupture of the rock sample the obvious ″tendency anomaly′ and ′short-term anomaly″ were observed, and some of them could be likely considered as the ″impending earthquake ″anomaly precursor of apparent resistivity. The changes and distribution features of apparent resistivity show that they are intrinsically related to the dilatancy phenomenon of the loaded rock sample. Finally, this paper discusses the mechanism of resistivity change of loaded rock sample theoretically.
基金Project(2024QN05053)supported by the Natural Science Foundation of Inner Mongolia,ChinaProjects(U24A20106,51931005,52171048)supported by the National Natural Science Foundation of ChinaProject(2020ZDLGY12-02)supported by the Key Industry Innovation Chain Project of Shaanxi Province,China。
文摘The microstructure,fracture mechanisms,deformation modes,and their correlation with the mechanical properties of Mg-Zn-Gd alloys were analyzed,considering the influence of Y and Nd additions.Increasing Y content and decreasing Nd content resulted in an increase in grain size from 17.2 to 29.2μm,and two types of LPSO phases,14 H and 18 R,formed in the alloy.The mechanical properties of the alloys were predominantly influenced by the LPSO phase,with the grain size effect being relatively minor.Based on this analysis,higher Y and lower Nd contents enhanced the tensile strength,yield strength,and elongation of the alloys,with additional improvements observed following solid solution treatment.Changes in Y and Nd content caused a shift in fracture patterns,transitioning from ductile fracture to brittle fracture and then to mixed fracture.Following solid solution treatment,the alloy progressively transitions from intergranular to a combination of ductile and deconvolutional fracture.The deformation modes observed at each stage are as follows:an increase in LPSO phases and twins activates pyramidal slip and suppresses prismatic slip.
基金funded by Science Foundation of China University of Petroleum, Beijing (No. 2462021YXZZ009)The Strategic Cooperation Technology Projects of CNPC and CUPB (No. ZLZX 2020-01)Innovation Capability Support of Shaanxi (Program No. 2023-CX-TD-31) Technical Innovation Team for Low Carbon Environmental Protection and Enhanced Oil Recovery in Unconventional Reservoirs。
文摘Supercritical CO_(2)(SC-CO_(2)) fracturing, being a waterless fracturing technology, has garnered increasing attention in the shale oil reservoir exploitation industry. Recently, a novel pre-SC-CO_(2) hybrid fracturing method has been proposed, which combines the advantages of SC-CO_(2) fracturing and hydraulic fracturing. However, the specific impacts of different pre-SC-CO_(2) injection conditions on the physical parameters, mechanical properties, and crack propagation behavior of shale reservoirs remain unclear. In this study, we utilize a newly developed “pre-SC-CO_(2) injection → water-based fracturing” integrated experimental device. Through experimentation under in-situ conditions, the impact of pre-SC-CO_(2) injection displacement and volume on the shale mineral composition, mechanical parameters, and fracture propagation behavior are investigated. The findings of the study demonstrate that the pre-injection SC-CO_(2) leads to a reduction in clay and carbonate mineral content, while increasing the quartz content. The correlation between quartz content and SC-CO_(2) injection volume is positive, while a negative correlation is observed with injection displacement. The elastic modulus and compressive strength exhibit a declining trend, while Poisson's ratio shows an increasing trend. The weakening of shale mechanics caused by pre-injection of SC-CO_(2) is positively correlated with the injection displacement and volume.Additionally, pre-injection of SC-CO_(2) enhances the plastic deformation behavior of shale, and its breakdown pressure is 16.6% lower than that of hydraulic fracturing. The breakdown pressure demonstrates a non-linear downward trend with the gradual increase of pre-SC-CO_(2) injection parameters.Unlike hydraulic fracturing, which typically generates primary fractures along the direction of the maximum principal stress, pre-SC-CO_(2) hybrid fracturing leads to a more complex fracture network. With increasing pre-SC-CO_(2) injection displacement, intersecting double Y-shaped complex fractures are formed along the vertical axis. On the other hand, increasing the injection rate generates secondary fractures along the direction of non-principal stress. The insights gained from this study are valuable for guiding the design of pre SC-CO_(2) hybrid fracturing in shale oil reservoirs.
基金The fnancial support of the Research Council of the Katholieke Universiteit Leuven(OT-project OT/03/35)
文摘The experimental study in this paper focuses on the effects of the layer orientation and sample shape on failure strength and fracture pattern of samples tested under Brazilian test conditions(i.e.diametrical loading of cylindrical discs)for one particular layered sandstone which is from Modave in the south of Belgium.The variations of the strength in combination with the failure patterns are examined as a function of the inclination angle between the layer plane and the loading direction.The experimental,results clearly show that the induced fracture patterns are a combination of tensile and/or shear fractures.In shape effect experiments the layer thickness and the number of layer boundaries are investigated.Different blocks of Modave sandstone are used to prepare samples.The layer thickness is different among the various blocks,but the layer thickness in each studied rock block can be considered to be constant;hence,the number of layer boundaries changes according to the sample diameter for samples of the same block.The experimental study shows that the layer thickness plays a more important role than the number of layer boundaries per sample.
基金the Science and Technology Commission of Shanghai Municipality,China,under the Science and Technology Planning Project(Grant number:21410760200).
文摘A thorough understanding of the fracture characteristics can assist the decision-making process for surgery.This study aimed to characterize the femoral neck fractures among middle-aged patients and illustrated a biomedical visualization method using a fracture mapping model and augmented reality.We collected plain radiography and computed tomography(CT)data from 156 adult patients with a femoral neck fracture.The descriptive study showed that Type I and Type II fractures accounted for 8(5%)and 64(41%)cases.In comparison,Type IV fractures accounted for 44(28%)and 40(25%)cases according to the Garden classification.Comminuted fractures and cortical defects were identified in 14.74%and 29.49%of the cases.A fracture mapping model was reconstructed based on the CT data and demonstrated the location and distribution of the major fracture lines surrounding the head-neck junction.We also illustrated the application of augmented reality technology to visualize and interact with the patient-specific fracture model and the fracture mapping model that facilitated education,training,and surgical planning.Future studies may consider mapping other biomechanical data,such as joint loading and stress distribution,and exploring artificial intelligence via deep reinforcement learning for computer-aided fracture reduction and procedure planning.
基金supported by the International Science&Technology Cooperation Program of China(Grant No.2016YFE0102200)and the National Natural Science Foundation of China(Grant Nos.51675294 and U1564205)+1 种基金sponsored by Ford URP(University Research Program)State Key Laboratory of Vehicle NVH and Safety Technology(Grant No.NVHSKL-201604)
文摘In the study, mechanical abuse tests mainly in the form of indentation were performed on the cylindrical cell, pouch cell, and prismatic cell. The mechanical force-displacement response, open circuit voltage(OCV), and temperature distribution were recorded and compared. In spherical head indentation tests of the pouch and prismatic cell and lateral indentation of the cylindrical cell, the peak force is strongly correlated with OCV drop and local temperature increase. However, in flat-end cylinder indentation tests, the internal mechanical damage is progressively developed, and the OCV drop and the temperature increase occur before the peak force. The fracture surfaces of the post-mortem samples were examined to investigate the correlation between fracture patterns and internal short circuit(ISC) behaviors(OCVand temperature distribution). Two distinct fracture patterns were observed that the in-plane fracture induced by biaxial stretching and inter-layers' fracture induced by shearing. A strong correlation is observed between the number of shear fractures and OCV drop. An increase in the number of inter-layers' fractures increases the rate of OCV drop. Additionally, the fracture patterns influence the ISC area and location,thereby affecting the heat generation and conduction as well as the temperature distribution.
