These clearly demonstrate that the mcc formatted by long - history processes with poly stages . by strain analysis , the fabrics deformational style of the yagan mcc are mainly shearing type , the yagan mcc is mainly a thinning shear zone with volume loss , which varies from - 31 % ~ - 58 % . analysis of kinematic vorticity ( wk varies from 0 . 453 - 0 . 809 ) shows shear type of the shear zone is neither pure shear nor simple shear but general shear 应变分析表明，亚干变质核杂岩主期变形为以剪切变形为主(罗德系数u在0 . 08 ? 0 . 32间)压扁次之( u0 . 89 )的变形类型，核杂岩区为一有体积损失的减薄型剪切带，体积损失率达- 31 ? - 58 。
The following conclusions are gained : ( 1 ) the located shear band prongs the ligament near the top crack tip and the structure may occur shear - mode fracture at the angle of 155 ? to crack when load is 87 . 92mpa ; the mode of fracture of the flange joint structure is not possible to be void - mode ; ( 2 ) it is proved that loading and then unloading repeatedly can not increase the possibility of invalidation of the structure when the times of loading and unloading are not too more when load is operating pressure ; the structure is safe when the vessel is operating ; ( 3 ) in the fe model of the thesis , not considering the influence of water pressure test which is in the process of fabrication of vessel in fe results in larger deviation in analysi 得出了以下结论：在8792mpa的载荷下筒体一封头连接结构处的集中剪切带贯穿韧带，可能发生沿与原裂纹线成155 “角方向剪切型断裂；筒体一封头连接结构不可能发生韧窝型断裂； （ 2 ）在工作压力下进行次数不多的反复加、卸载，结构不会破坏，也不会丧失安定性：结构在工作状态下是安全的； m在本文的弹塑性有限元模拟计算中，对于裂纹尖端进行力学分析时，不考虑压力容器制造过程中水压试验的影响，将导致计算结果出现较大的偏差； （ 4 ）筒体完全屈服时的载荷为92石3mpa ，封头完全屈服时载荷为86
Author thinks that the direction of the maximum plastic distortion along a constant radius around the crack tip may be considered as the direction of shear - mode fracture ( named pmax - criterion ) and the load when located shear band prongs the ligament in the front of crack tip is regarded as the limited load of shear - mode fracture . ( 3 ) the fad ( fracture assessment diagram ) of titled crack is proposed based on achievements of mesomechanics about i - ii complex ductile fracture of metal , and the titled crack is classified two kinds : void - mode fracture is assessed by fracture assessment curve , and shear - mode fracture by limited load . ( 4 ) using a fe program based on plantle - ressue theory to calculate some mesomechanical parameters , a flange joint structure of a high pressure vessel ( design pressure 31 . 4mpa and the thickness of the hemispherical head is half of that of shell . ) is analyzed to determine whether the structure under operation pressure is safe or not , forecast the mode of potential invalidation and argue for the rationality of design of the structure 试件的整体断裂为剪切型，但在试件芯部裂尖钝化区中部出现了韧窝型启裂并有一定的扩展，说明局部较高的应力三轴度也会使韧窝型机制得以发展，但是不改变试件整体的剪切型断裂模式；对韧性断裂的剪切模式的细观机理做了一定的探讨，并且提出了含裂纹构件剪切型断裂的宏观判据：认为裂纹前方的集中剪切带中与裂纹尖端等半径处最大有效塑性应变出现的方向可以作为裂纹剪切断裂的方向(可简称为_ ( pmax )准则) ，集中剪切滑移带贯穿裂纹前方承载韧带时的载荷可以作为极限载荷；本文运用金属韧性断裂细观力学在一复合型韧性断裂方面的研究成果，采用失效评定图的形式，提出了倾斜裂纹的安全性评定方法的基本框架。
