Self-piercing riveting(SPR)is a cold forming technique used to fasten together two or more sheets of materials with a rivet without the need to predrill a hole.The application of SPR in the automotive sector has becom...Self-piercing riveting(SPR)is a cold forming technique used to fasten together two or more sheets of materials with a rivet without the need to predrill a hole.The application of SPR in the automotive sector has become increasingly popular mainly due to the growing use of lightweight materials in transportation applications.However,SPR joining of these advanced light materials remains a challenge as these materials often lack a good combination of high strength and ductility to resist the large plastic deformation induced by the SPR process.In this paper,SPR joints of advanced materials and their corresponding failure mechanisms are discussed,aiming to provide the foundation for future improvement of SPR joint quality.This paper is divided into three major sections:1)joint failures focusing on joint defects originated from the SPR process and joint failure modes under different mechanical loading conditions,2)joint corrosion issues,and 3)joint optimisation via process parameters and advanced techniques.展开更多
Out-of-plane mechanical properties of the riveted joints restrict the performance of the wing box assembly of airplane.It is necessary to investigate the pull-through performance of the composite/metal riveted joints ...Out-of-plane mechanical properties of the riveted joints restrict the performance of the wing box assembly of airplane.It is necessary to investigate the pull-through performance of the composite/metal riveted joints in order to guide the riveting design and ensure the safety of the wing box assembly.The progressive failure mechanism of composite/aluminum riveted joint subjected to pull-through loading was investigated by experiments and finite element method.A progressive damage model based on the Hashin-type criteria and zero-thickness cohesive zone method was developed by VUMAT subroutine,which was validated by both open-hole tensile test and three-point bending test.Predicted load-displacement response,failure modes and damage propagation were analysed and compared with the results of the pull-through tests.There are 4 obvious characteristic stages on the load-displacement curve of the pull-through test and that of the finite element model:first load take-up stage,damage stage,second load take-up stage and failure stage.Relative error of stiffness,first load peak and second load peak between finite element method and experiments were 8.1%,-3.3%and 10.6%,respectively.It was found that the specimen was mainly broken by rivet-penetration fracture and delamination of plies of the composite laminate.And the material within the scope of the rivet head is more dangerous with more serious tensile damages than other regions,especially for 90°plies.This study proposes a numerical method for damage prediction and reveals the progressive failure mechanism of the hybrid material riveted joints subjected to the pull-through loading.展开更多
A new testing methodology was developed to quantitively study galvanic corrosion of AZ31B and thermoset carbon-fiber–reinforced polymer spot-joined by a friction self-piercing riveting process.Pre-defined areas of AZ...A new testing methodology was developed to quantitively study galvanic corrosion of AZ31B and thermoset carbon-fiber–reinforced polymer spot-joined by a friction self-piercing riveting process.Pre-defined areas of AZ31B in the joint were exposed in 0.1 M NaCl solution over time.Massive galvanic corrosion of AZ31B was observed as exposure time increased.The measured volume loss was converted into corrosion current that was at least 48 times greater than the corrosion current of AZ31B without galvanic coupling.Ninety percent of the mechanical joint integrity was retained for corroded F-SPR joints to 200 h and then decreased because of the massive volume loss of AZ31B。展开更多
Self-piercing riveting(SPR)has been widely used in automobile industry,and the strength prediction of SPR joints always attracts the attention of researchers.In this work,a prediction method of the cross-tension stren...Self-piercing riveting(SPR)has been widely used in automobile industry,and the strength prediction of SPR joints always attracts the attention of researchers.In this work,a prediction method of the cross-tension strength of SPR joints was proposed on the basis of finite element(FE)simulation and extreme gradient boosting decision tree(XGBoost)algorithm.An FE model of SPR process was established to simulate the plastic deformations of rivet and substrate materials and verified in terms of cross-sectional dimensions of SPR joints.The residual mechanical field from SPR process simulation was imported into a 2D FE model for the cross-tension testing simulation of SPR joints,and cross-tension strengths from FE simulation show a good consistence with the experiment result.Based on the verified FE model,the mechanical properties and thickness of substrate materials were varied and then used for FE simulation to obtain cross-tension strengths of a number of SPR joints,which were used to train the regression model based on the XGBoost algorithm in order to achieve prediction for cross-tension strength of SPR joints.Results show that the cross-tension strengths of SPR steel/aluminum joints could be successfully predicted by the XGBoost regression model with a respective error less than 7.6%compared to experimental values.展开更多
This paper studies the effects of fiber orientaion and holes position on stress concentration and the determination of weakened areas in the composite of glass fiber reinforced epoxy resin around the hole for joints b...This paper studies the effects of fiber orientaion and holes position on stress concentration and the determination of weakened areas in the composite of glass fiber reinforced epoxy resin around the hole for joints by using the finite element method.In this study,for the observation of areas affected by stress concentration Tsai-Wu failure criterion is used to determine the failed elements and ANSYS Software is implemented for modeling.In order to compare the effect of geometric parameters on stress concentration around the holes,two types of hole position arrangement along with fibers orientation have been studied.Results show that the stress concentration coefficient is lower in the second type of holes arrangement in comparison with the first type for the same component dimensions.Increasing the distance from hole center to upper or lower edge of the sample and also decreasing the distance between holes,would result in an increase in the stress concentration.展开更多
目的 探讨异体肌腱联合带线铆钉治疗Ⅲ型肩锁关节脱位远期疗效。方法 选取2017年6月至2018年12月湖州市第一人民医院骨科收治的98例Ⅲ型肩锁关节脱位患者为研究对象,将入选患者根据治疗方式分为Dd组(带线铆钉治疗)和Lh组(异体肌腱联合...目的 探讨异体肌腱联合带线铆钉治疗Ⅲ型肩锁关节脱位远期疗效。方法 选取2017年6月至2018年12月湖州市第一人民医院骨科收治的98例Ⅲ型肩锁关节脱位患者为研究对象,将入选患者根据治疗方式分为Dd组(带线铆钉治疗)和Lh组(异体肌腱联合带线铆钉治疗),比较两组患者手术时间、术中出血量、住院时间、喙锁间距,术前及术后3个月、6个月美国肩肘外科协会评分(rating scale of the American Shoulder and Elbow Surgeons,ASES)、视觉模拟评分法(visual analogue scale,VAS)评分;1年后复查两组患者关节功能恢复情况。结果 Lh组患者手术时间和住院时间均显著长于Dd组(P<0.05),术中出血量显著多于Dd组(P<0.05)。术后3个月、6个月,两组患者ASES评分均显著高于术前(P<0.05),VAS评分均显著低于术前(P<0.05),喙锁间距测定值均显著小于术前(P<0.05);Lh组患者ASES评分均显著高于同期Dd组(P<0.05),VAS评分均显著低于同期Dd组(P<0.05),喙锁间距测定值均显著低于同期Dd组(P<0.05)。两组患者术后1年肩关节功能比较,差异无统计学意义(P>0.05)。Lh组患者并发症总发生率显著低于Dd组(P<0.05)。结论 异体肌腱联合带线铆钉治疗Ⅲ型肩锁关节脱位效果好于单独应用带线铆钉治疗,联合治疗远期疗效较好,并发症发生率低。展开更多
文摘Self-piercing riveting(SPR)is a cold forming technique used to fasten together two or more sheets of materials with a rivet without the need to predrill a hole.The application of SPR in the automotive sector has become increasingly popular mainly due to the growing use of lightweight materials in transportation applications.However,SPR joining of these advanced light materials remains a challenge as these materials often lack a good combination of high strength and ductility to resist the large plastic deformation induced by the SPR process.In this paper,SPR joints of advanced materials and their corresponding failure mechanisms are discussed,aiming to provide the foundation for future improvement of SPR joint quality.This paper is divided into three major sections:1)joint failures focusing on joint defects originated from the SPR process and joint failure modes under different mechanical loading conditions,2)joint corrosion issues,and 3)joint optimisation via process parameters and advanced techniques.
基金National Natural Science Foundation of China(Grant Nos.U21A20165,52205515,52105431)Applied Basic Research Program of Liaoning Province of China(Grant No.2022JH2/101300221)+2 种基金Dalian Science and Technology Innovation Fund of China(Grant No.2022JJ12GX033)National Key Research and Development Project of China(Grant No.2020YFB2009805)China Postdoctoral Science Foundation(Grant Nos.2020M680937,2020M670734)。
文摘Out-of-plane mechanical properties of the riveted joints restrict the performance of the wing box assembly of airplane.It is necessary to investigate the pull-through performance of the composite/metal riveted joints in order to guide the riveting design and ensure the safety of the wing box assembly.The progressive failure mechanism of composite/aluminum riveted joint subjected to pull-through loading was investigated by experiments and finite element method.A progressive damage model based on the Hashin-type criteria and zero-thickness cohesive zone method was developed by VUMAT subroutine,which was validated by both open-hole tensile test and three-point bending test.Predicted load-displacement response,failure modes and damage propagation were analysed and compared with the results of the pull-through tests.There are 4 obvious characteristic stages on the load-displacement curve of the pull-through test and that of the finite element model:first load take-up stage,damage stage,second load take-up stage and failure stage.Relative error of stiffness,first load peak and second load peak between finite element method and experiments were 8.1%,-3.3%and 10.6%,respectively.It was found that the specimen was mainly broken by rivet-penetration fracture and delamination of plies of the composite laminate.And the material within the scope of the rivet head is more dangerous with more serious tensile damages than other regions,especially for 90°plies.This study proposes a numerical method for damage prediction and reveals the progressive failure mechanism of the hybrid material riveted joints subjected to the pull-through loading.
基金financially sponsored by the US Department Energy Vehicle Technologies Office, as part of the Joining Core Programmanaged by UT-Battelle LLC for the US Department of Energy under Contract DE-AC05-00OR22725。
文摘A new testing methodology was developed to quantitively study galvanic corrosion of AZ31B and thermoset carbon-fiber–reinforced polymer spot-joined by a friction self-piercing riveting process.Pre-defined areas of AZ31B in the joint were exposed in 0.1 M NaCl solution over time.Massive galvanic corrosion of AZ31B was observed as exposure time increased.The measured volume loss was converted into corrosion current that was at least 48 times greater than the corrosion current of AZ31B without galvanic coupling.Ninety percent of the mechanical joint integrity was retained for corroded F-SPR joints to 200 h and then decreased because of the massive volume loss of AZ31B。
基金Supported by National Natural Science Foundation of China(Grant No.51805375).
文摘Self-piercing riveting(SPR)has been widely used in automobile industry,and the strength prediction of SPR joints always attracts the attention of researchers.In this work,a prediction method of the cross-tension strength of SPR joints was proposed on the basis of finite element(FE)simulation and extreme gradient boosting decision tree(XGBoost)algorithm.An FE model of SPR process was established to simulate the plastic deformations of rivet and substrate materials and verified in terms of cross-sectional dimensions of SPR joints.The residual mechanical field from SPR process simulation was imported into a 2D FE model for the cross-tension testing simulation of SPR joints,and cross-tension strengths from FE simulation show a good consistence with the experiment result.Based on the verified FE model,the mechanical properties and thickness of substrate materials were varied and then used for FE simulation to obtain cross-tension strengths of a number of SPR joints,which were used to train the regression model based on the XGBoost algorithm in order to achieve prediction for cross-tension strength of SPR joints.Results show that the cross-tension strengths of SPR steel/aluminum joints could be successfully predicted by the XGBoost regression model with a respective error less than 7.6%compared to experimental values.
文摘This paper studies the effects of fiber orientaion and holes position on stress concentration and the determination of weakened areas in the composite of glass fiber reinforced epoxy resin around the hole for joints by using the finite element method.In this study,for the observation of areas affected by stress concentration Tsai-Wu failure criterion is used to determine the failed elements and ANSYS Software is implemented for modeling.In order to compare the effect of geometric parameters on stress concentration around the holes,two types of hole position arrangement along with fibers orientation have been studied.Results show that the stress concentration coefficient is lower in the second type of holes arrangement in comparison with the first type for the same component dimensions.Increasing the distance from hole center to upper or lower edge of the sample and also decreasing the distance between holes,would result in an increase in the stress concentration.
文摘目的 探讨异体肌腱联合带线铆钉治疗Ⅲ型肩锁关节脱位远期疗效。方法 选取2017年6月至2018年12月湖州市第一人民医院骨科收治的98例Ⅲ型肩锁关节脱位患者为研究对象,将入选患者根据治疗方式分为Dd组(带线铆钉治疗)和Lh组(异体肌腱联合带线铆钉治疗),比较两组患者手术时间、术中出血量、住院时间、喙锁间距,术前及术后3个月、6个月美国肩肘外科协会评分(rating scale of the American Shoulder and Elbow Surgeons,ASES)、视觉模拟评分法(visual analogue scale,VAS)评分;1年后复查两组患者关节功能恢复情况。结果 Lh组患者手术时间和住院时间均显著长于Dd组(P<0.05),术中出血量显著多于Dd组(P<0.05)。术后3个月、6个月,两组患者ASES评分均显著高于术前(P<0.05),VAS评分均显著低于术前(P<0.05),喙锁间距测定值均显著小于术前(P<0.05);Lh组患者ASES评分均显著高于同期Dd组(P<0.05),VAS评分均显著低于同期Dd组(P<0.05),喙锁间距测定值均显著低于同期Dd组(P<0.05)。两组患者术后1年肩关节功能比较,差异无统计学意义(P>0.05)。Lh组患者并发症总发生率显著低于Dd组(P<0.05)。结论 异体肌腱联合带线铆钉治疗Ⅲ型肩锁关节脱位效果好于单独应用带线铆钉治疗,联合治疗远期疗效较好,并发症发生率低。
