The dimpling defects caused by conventional hemispherical punch in doubly curved sheet metal reconfigurable die forming process were considered.The rotatable cubic punch (RCP) was developed to suppress the dimpling de...The dimpling defects caused by conventional hemispherical punch in doubly curved sheet metal reconfigurable die forming process were considered.The rotatable cubic punch (RCP) was developed to suppress the dimpling defects more effectively and conveniently.The former punch contacts with the work-piece through a point-surface contact and the latter punch contacts with the work-piece through a surface-surface contact.A series of stamping experiments were carried out using three different punches (hemispherical punch,RCP,chamfered-RCP) with three different loads.Some finite element simulations about the stamping experiments were carried out.The dimple scales were evaluated through the dimple depths.The corresponding data were obtained by 3-D scanning and FE result analysis respectively.A 3-D plate forming machine was developed,in which chamfered-RCP was adopted.Plate forming experiments were carried out on this machine.The stamped samples show a clear basis for the performance of chamfered-RCP.The study provided a means to guide the design of punches for dimpling suppression used in reconfigurable die.展开更多
目的:分析应用掌侧接骨板方法治疗桡骨远端die-punch骨折的临床可行性。方法:选取我院2014年12月~2015年12月已接受掌侧接骨板治疗的远端die-punch骨折患者32例为对象。32例患者的die-punch骨折类型主要有三种,为纵向劈裂类型、掌侧类...目的:分析应用掌侧接骨板方法治疗桡骨远端die-punch骨折的临床可行性。方法:选取我院2014年12月~2015年12月已接受掌侧接骨板治疗的远端die-punch骨折患者32例为对象。32例患者的die-punch骨折类型主要有三种,为纵向劈裂类型、掌侧类型、背侧类型。治疗所用的接骨板的类型为万向双柱锁定加压类型及2.4 mm T类型。患者手术后选择性进行一些功能恢复训练,如术后1个月内行手掌和指关节的活动,术后超1个月行腕关节活动训练。对32例患者进行随访,相关内容有X片、DASH评分、腕部是否出现畸形、并发症情况、握力、腕关节活动情况。探究采用不同die-punch骨折类类型和不同接骨板类型患者之间上述指标的差异。结果:成功随访了32例患者,经X片发现骨折愈合状况良好,且关节面也较为平整,未出现并发症和腕部畸形现象。不同die-punch骨折类型和不同接骨板类型患者DASH评分、握力、腕关节活动状况差异均无统计学意义(P>0.05)。结论:应用掌侧接骨板方法治疗桡骨远端die-punch骨折具有临床可行性。展开更多
Based on the elastoplastic mechanical properties of the weld and heat affected zone metals obtained by a nanoindentation test, a theoretical calculation model was established for the forming limit diagram（FLD） of ta...Based on the elastoplastic mechanical properties of the weld and heat affected zone metals obtained by a nanoindentation test, a theoretical calculation model was established for the forming limit diagram（FLD） of tailor-welded blanks（TWBs） on the basis of plastic constitutive relations and Hosford yield criteria. Hemispherical punch bulging tests were performed to verify the FLD theoretical calculation results. The results demonstrated that not only the FLD theoretical calculation of base materials but also that of TWBs had a good agreement with their experiments. Besides, poorer formability of TWBs caused its FLD significantly lower than that of base materials. The theoretical calculation model offers a reliable approach to obtain the specific FLD of TWBs.展开更多
Experimental and numerical analyses for the effect of the thickness of gap generator blank（GGB） on the formability of the outer blanks were investigated. The thickness of the GGB has the greatest impact on the thinn...Experimental and numerical analyses for the effect of the thickness of gap generator blank（GGB） on the formability of the outer blanks were investigated. The thickness of the GGB has the greatest impact on the thinning of the lowest blank. In addition, the friction at different regions and the additional interlayer contacts can also affect the thinning of different regions as well as increase the punch force. This work will enhance the understanding of simultaneous multi-layered blanks forming and will help the composite design engineers to tailor requirement-specific hybrid parts such as fiber metal laminates（FMLs） and functionally graded structures（FGSs） for hi-tech applications.展开更多
基金the National Natural Science Foundation of China(Nos.51379167 and 51779200)。
文摘The dimpling defects caused by conventional hemispherical punch in doubly curved sheet metal reconfigurable die forming process were considered.The rotatable cubic punch (RCP) was developed to suppress the dimpling defects more effectively and conveniently.The former punch contacts with the work-piece through a point-surface contact and the latter punch contacts with the work-piece through a surface-surface contact.A series of stamping experiments were carried out using three different punches (hemispherical punch,RCP,chamfered-RCP) with three different loads.Some finite element simulations about the stamping experiments were carried out.The dimple scales were evaluated through the dimple depths.The corresponding data were obtained by 3-D scanning and FE result analysis respectively.A 3-D plate forming machine was developed,in which chamfered-RCP was adopted.Plate forming experiments were carried out on this machine.The stamped samples show a clear basis for the performance of chamfered-RCP.The study provided a means to guide the design of punches for dimpling suppression used in reconfigurable die.
文摘目的:分析应用掌侧接骨板方法治疗桡骨远端die-punch骨折的临床可行性。方法:选取我院2014年12月~2015年12月已接受掌侧接骨板治疗的远端die-punch骨折患者32例为对象。32例患者的die-punch骨折类型主要有三种,为纵向劈裂类型、掌侧类型、背侧类型。治疗所用的接骨板的类型为万向双柱锁定加压类型及2.4 mm T类型。患者手术后选择性进行一些功能恢复训练,如术后1个月内行手掌和指关节的活动,术后超1个月行腕关节活动训练。对32例患者进行随访,相关内容有X片、DASH评分、腕部是否出现畸形、并发症情况、握力、腕关节活动情况。探究采用不同die-punch骨折类类型和不同接骨板类型患者之间上述指标的差异。结果:成功随访了32例患者,经X片发现骨折愈合状况良好,且关节面也较为平整,未出现并发症和腕部畸形现象。不同die-punch骨折类型和不同接骨板类型患者DASH评分、握力、腕关节活动状况差异均无统计学意义(P>0.05)。结论:应用掌侧接骨板方法治疗桡骨远端die-punch骨折具有临床可行性。
基金Project(51275444) supported by the National Natural Science Foundation of ChinaProject(20121333110003) supported by the Specialized Research Fund for the Doctoral Program of Higher Education,China+1 种基金Project(E2014203271) supported by the Natural Science Foundation–Steel and Iron Foundation of Hebei ProvinceChina
文摘Based on the elastoplastic mechanical properties of the weld and heat affected zone metals obtained by a nanoindentation test, a theoretical calculation model was established for the forming limit diagram（FLD） of tailor-welded blanks（TWBs） on the basis of plastic constitutive relations and Hosford yield criteria. Hemispherical punch bulging tests were performed to verify the FLD theoretical calculation results. The results demonstrated that not only the FLD theoretical calculation of base materials but also that of TWBs had a good agreement with their experiments. Besides, poorer formability of TWBs caused its FLD significantly lower than that of base materials. The theoretical calculation model offers a reliable approach to obtain the specific FLD of TWBs.
基金Project(2010DFA52030)supported by the International Scientific Cooperation,ChinaProject(51175024)supported by the National Natural Science Foundation of China
文摘Experimental and numerical analyses for the effect of the thickness of gap generator blank（GGB） on the formability of the outer blanks were investigated. The thickness of the GGB has the greatest impact on the thinning of the lowest blank. In addition, the friction at different regions and the additional interlayer contacts can also affect the thinning of different regions as well as increase the punch force. This work will enhance the understanding of simultaneous multi-layered blanks forming and will help the composite design engineers to tailor requirement-specific hybrid parts such as fiber metal laminates（FMLs） and functionally graded structures（FGSs） for hi-tech applications.
