Crane Hooks are highly liable components and are always subjected to failure due to accumulation of large amount of stresses which can eventually lead to its failure. To study the stress pattern of crane hook in its l...Crane Hooks are highly liable components and are always subjected to failure due to accumulation of large amount of stresses which can eventually lead to its failure. To study the stress pattern of crane hook in its loaded condition, a solid model of crane hook is prepared with the help of CMM and CAD software. Real time pattern of stress concentration in 3D model of crane hook is obtained. The stress distribution pattern is verified for its correctness on an acrylic model of crane hook using Diffused light Polariscope set up. By predicting the stress concentration area, the shape of the crane is modified to increase its working life and reduce the failure rates.展开更多
Though the preferred welding process to weld aluminium alloy is frequently constant current gas tungsten arc welding (CCGTAW),it resulted in grain coarsening at the fusion zone and heat affected zone(HAZ).Hence,pulsed...Though the preferred welding process to weld aluminium alloy is frequently constant current gas tungsten arc welding (CCGTAW),it resulted in grain coarsening at the fusion zone and heat affected zone(HAZ).Hence,pulsed current gas tungsten arc welding(PCGTAW) was performed,to yield finer fusion zone grains,which leads to higher strength of AA6061 (Al-Mg-Si) aluminium alloy joints.In order to determine the most influential control factors which will yield minimum fusion zone grain size and maximum tensile strength of the joints,the traditional Hooke and Jeeves pattern search method was used.The experiments were carried out based on central composite design with 31 runs and an algorithm was developed to optimize the fusion zone grain size and the tensile strength of pulsed current gas tungsten arc welded AA6061 aluminium alloy joints.The results indicate that the peak current (Ip) and base current (IB) are the most significant parameters,to decide the fusion zone grain size and the tensile strength of the AA6061 aluminum alloy joints.展开更多
排气系统挂钩悬挂位置选取不准确极易导致汽车行驶过程中产生异响及振动,准确地选取排气系统挂钩悬挂位置极为重要。根据排气系统振动模态提取的挂钩悬挂位置,加权后采用均方根值(Root Mean Square,RMS)法进行数据处理,得到振动模态位...排气系统挂钩悬挂位置选取不准确极易导致汽车行驶过程中产生异响及振动,准确地选取排气系统挂钩悬挂位置极为重要。根据排气系统振动模态提取的挂钩悬挂位置,加权后采用均方根值(Root Mean Square,RMS)法进行数据处理,得到振动模态位移的均方根值法排气系统挂钩悬挂点布置。将采用平均驱动自由度位移(Average Driving Degree Of Freedom Displacement,ADDOFD)法得到的排气系统挂钩悬挂位置与采用均方根值法得到的悬挂位置进行对比验证。研究结果表明,使用均方根值法得到的排气系统挂钩悬挂位置在SUV上更加有效;均方根值法布点效率高于平均驱动自由度位移法,缩短了设计周期。展开更多
目的探讨以"挂钩"的方式顺行置入双J管在腹腔镜肾盂成形术中的应用。方法 2014年10月~2016年5月对28例肾盂输尿管连接部梗阻行腹腔镜肾盂成形术,在完成肾盂输尿管连接部后壁的缝合后,双J管以"挂钩"的方式顺行置入...目的探讨以"挂钩"的方式顺行置入双J管在腹腔镜肾盂成形术中的应用。方法 2014年10月~2016年5月对28例肾盂输尿管连接部梗阻行腹腔镜肾盂成形术,在完成肾盂输尿管连接部后壁的缝合后,双J管以"挂钩"的方式顺行置入输尿管内,双J管远端进入膀胱内,撤出导丝及推管,腹腔镜弯钳将双J管近端放置肾盂内,完成肾盂输尿管连接部的前壁缝合。结果 28例双J管均以顺行方式顺利置入,围手术期无并发症发生。镜下置管时间2 min 30 s^4 min 45 s,平均3 min 5 s。术后4~6周拔除双J管,复查泌尿系超声或静脉肾盂造影,肾积水较术前减轻(术前中度17例,重度11例;术后中度9例,轻度13例,无肾积水6例)。结论顺行"挂钩"法置入双J管安全、操作简便,利用双J管自身的优势,不需要额外辅助器械,为腹腔镜肾盂成形手术中置入双J管提供一种新的思路。展开更多
文摘Crane Hooks are highly liable components and are always subjected to failure due to accumulation of large amount of stresses which can eventually lead to its failure. To study the stress pattern of crane hook in its loaded condition, a solid model of crane hook is prepared with the help of CMM and CAD software. Real time pattern of stress concentration in 3D model of crane hook is obtained. The stress distribution pattern is verified for its correctness on an acrylic model of crane hook using Diffused light Polariscope set up. By predicting the stress concentration area, the shape of the crane is modified to increase its working life and reduce the failure rates.
基金Naval Research Board (NRB),Ministry of Defence,New Delhi for the financial support to carry out this investigation through sponsored project No.DNRD/05/4003/NRB/67.
文摘Though the preferred welding process to weld aluminium alloy is frequently constant current gas tungsten arc welding (CCGTAW),it resulted in grain coarsening at the fusion zone and heat affected zone(HAZ).Hence,pulsed current gas tungsten arc welding(PCGTAW) was performed,to yield finer fusion zone grains,which leads to higher strength of AA6061 (Al-Mg-Si) aluminium alloy joints.In order to determine the most influential control factors which will yield minimum fusion zone grain size and maximum tensile strength of the joints,the traditional Hooke and Jeeves pattern search method was used.The experiments were carried out based on central composite design with 31 runs and an algorithm was developed to optimize the fusion zone grain size and the tensile strength of pulsed current gas tungsten arc welded AA6061 aluminium alloy joints.The results indicate that the peak current (Ip) and base current (IB) are the most significant parameters,to decide the fusion zone grain size and the tensile strength of the AA6061 aluminum alloy joints.
文摘排气系统挂钩悬挂位置选取不准确极易导致汽车行驶过程中产生异响及振动,准确地选取排气系统挂钩悬挂位置极为重要。根据排气系统振动模态提取的挂钩悬挂位置,加权后采用均方根值(Root Mean Square,RMS)法进行数据处理,得到振动模态位移的均方根值法排气系统挂钩悬挂点布置。将采用平均驱动自由度位移(Average Driving Degree Of Freedom Displacement,ADDOFD)法得到的排气系统挂钩悬挂位置与采用均方根值法得到的悬挂位置进行对比验证。研究结果表明,使用均方根值法得到的排气系统挂钩悬挂位置在SUV上更加有效;均方根值法布点效率高于平均驱动自由度位移法,缩短了设计周期。
文摘目的探讨以"挂钩"的方式顺行置入双J管在腹腔镜肾盂成形术中的应用。方法 2014年10月~2016年5月对28例肾盂输尿管连接部梗阻行腹腔镜肾盂成形术,在完成肾盂输尿管连接部后壁的缝合后,双J管以"挂钩"的方式顺行置入输尿管内,双J管远端进入膀胱内,撤出导丝及推管,腹腔镜弯钳将双J管近端放置肾盂内,完成肾盂输尿管连接部的前壁缝合。结果 28例双J管均以顺行方式顺利置入,围手术期无并发症发生。镜下置管时间2 min 30 s^4 min 45 s,平均3 min 5 s。术后4~6周拔除双J管,复查泌尿系超声或静脉肾盂造影,肾积水较术前减轻(术前中度17例,重度11例;术后中度9例,轻度13例,无肾积水6例)。结论顺行"挂钩"法置入双J管安全、操作简便,利用双J管自身的优势,不需要额外辅助器械,为腹腔镜肾盂成形手术中置入双J管提供一种新的思路。
