用拘束度与拘束应力对对接接头裂纹试验的评定

本文根据拉伸拘束度的概念,建立了拘束度测量装置,对造船业中常用的铁研型、里海型、直缝型、H 型、刚性对接(巴东)型、窗型等对接接头裂纹试样的拘束度测量表明,H 型试样拘束度系数最大,窗型试样拘束度系数最小。相同试验焊缝长度下,铁研试样拘束度系数最大。同时,在某船船体大合拢建造过程中进行了拘束度测量。结果表明,在相同试验焊缝长度下,实船与铁研及刚性对接裂纹试样的拘束度相吻合。用切割释放应力电测法测量了铁研、刚性对接试样焊缝的拘束应力。结果表明,在一定结构型式下拘束度大小是结构拘束程度的判据。在二维应力状态下,不同结构型式的试样,其拘束度与拘束应力不完全有对应关系。

AN EVALUATION FOR BUTT JOINT CRACKING TESTS IN TERMS OF RESTRAINT SEVERITY AND RESTRAINT STRESS

An apparatus for measuring the restraint severity has been set up based on the concept of tensile restraint severity.The restraint severity of butt weld cracking specimens usually used in shipbuilding has been measured.The types of these specimens are the Tekken type,Lehigh type,Straight Slit type with circular holes at the ends,H-type,restraint butt joint and window type,etc.The results show that the restraint coefficient of H-type cracking specimen is highest and that of window type is lowest.At the same time,the measurements of the restraint severity are performed for joints connecting one block of a ship to another.The measurements indicate that at the same slit length there is a good agreement between the restraint severity of the ship structure and that of the Tekken type and restraint butt joint cracking specimens.The restraint stresses of the Tekken type and restraint butt joint cracking specimens are measured by means of the relieving stress electrometrical method.The experimental results indicate also that for a given configuration,the amount of restraint severity is a criterion for predicting the extent of restraint for the structure.In twodimentional stress state,the corresponding relationship between restraint severity and restraint stress for different specimen configurations is not always in existence.