往复泵曲轴断裂失效分析

应用理化检验对某往复泵曲轴断裂事故进行了宏观检查、材质化学成分分析、硬度测试、金相组织分析、断口形貌分析等检测。结果表明,曲轴断裂为多源疲劳断裂。主要原因是由于曲轴材质金相组织不均匀,不同部位硬度差异较大,内部夹杂物较多,曲轴的化学元素存在偏析,碳质量分数偏高,加之曲轴表面镀层厚度不均匀,镀层和基体的结合不好,在结合处产生应力集中等引起的疲劳断裂。据此,提出了相应的改进措施。     

蠕变条件下完整岩石的起裂和扩展准则

The mechanism and criterion of crack initiation and propagation of rocks were investigated by many researchers,And the creep behaviour of rocks was also theoretically and experimentally studied by some scientists and engineers.The characteristics of crack initation and propagation of rocks under creep condition.however,are very improtant for rock engineering and still not paid enough attention by researchers,In this paper,the criterion and mechanism of crack initiation and propagation under creep condition were investigated using specimens collected from sandstone rock formations outcropping in the Emei Mountain,the Sichuan Province of China.Cuboid specimens under three point bending were used in this investigation.All specimens were classified into four sorts and used for Mode-I fracutre of creep frcture tests.The experimental result shows that due to creep deformation.rock crack will inevitably initialt and propagate under a load of KI,which is less than fracture toughness KIC but not less than a constant(marked as KIC2),KIC2 indicates the ability of rock to resist crack initiation and propagation under creep conditions and is less than fracture tough ness KIC.defined as creep fracture toughness in this paper,KIC2 should be considered as an importnat parameter on design and computation of rock engineering.The microstructureal mechanism for crack initiation and propagation of rock materials under creep condition was introduced based on competitive model between softening effect and hardening effect,and the validity of test result was explained.The test result was also verified in rheological theory.When KI is more than KIC2 but less than KIC,rock crack will initiate and propagate after a time interval of sustained loading under creep condition.In order to find the relation between duration of sustained lading.which can lead to crack initiation and propagation,and the initial stress intensity factor KI,an unequal0interval time sequence forecasting and predicting model was introduced,and the relation was obtained for homogeneous and isotropic fine-grained red sandstone.Finally a modified fracture toughness formula was given,in which the influence of fracture process zone(FPZ) was fully considered.     

关于裂尖分枝模型在复合型断裂准则研究中的应用

关于裂尖分枝模型在复合型断裂准则研究中的应用早在１９７３年，Ｈｕｓｓａｉｎ等人提出了分枝裂纹尖端应力场强度的解析解￣［１］．随后，许多人对该解的正确性及合理性提出异议￣［２，３］．文献［４］将该封闭解引入复合型裂纹的断裂准则的研究，从结果看由此准则可...     

论醚键的酸催化断裂反应

文章讨论了醚键的酸催化断裂反应,重点论述了底物的的结构和亲核试剂的改变对亲核取代反应历程以及对生成物结构的影响     

运动创伤性跟腱断裂的功能重建

本文报告运动创伤性跟腱断裂２１例,新鲜损伤１７例,陈旧损伤４例,均行手术治疗,其中１８例经１～５年的随访,优良率为：８８．９％。新鲜损伤的病人疗效满意     

鸡西电厂新建工程区域稳定分析与评价

在火力发电厂的可行性研究阶段,应对厂址方案的稳定性作出最终评价。针对本工程较为复杂的工程地质条件,本文从地质条件、地震情况、断裂及构造运动出发,对场址区的区域稳定性做出分析与评价。     

抽油杆断裂原因分析及对策

随着采出程度的提高,油田在开发过程中不断地出现一些新的矛盾和技术难题,诸如抽油杆组合不合理、最大拉应力破坏、偏磨造成抽油杆损坏等使抽油杆断裂;由于油田采出程度较高,含水上升快,腐蚀、结蜡造成的影响、供液不足造成的影响等使抽油杆断裂;这日益成为影响油井正常生产的难题;针对这些矛盾和技术难题,通过深化对管杆分析认识,2007年开展了一系列油杆组合调整、老井措施挖潜和采油新工艺实施,取得了良好开发效果和经济效益。     

短跑训练对跟腱横截面积和弹性模量的影响

通过对短跑运动员和非运动员跟腱横截面积和弹性模量的研究后发现,短跑运动员和非运动员相比,跟腱的横截面积无显著性变化,弹性模量则明显增加,其差异有显著性,表明短跑训练后肌腱能够承受更大的应力可能是通过内部结构的改变而不是通过增粗、肥大来实现的.     

支架底座断裂处理方案

通过对1492(1)工作面第106#支架断裂底座成功更换,详细分析支架底座断裂后的处理方案及技术要点,对今后深水平高地压工作面支架底座断裂后提供了安全快速的处理经验。     

招平断裂带上盘金矿床石英流体包裹体同位素组成特征及地质意义

招-平断裂是胶东招掖金矿带的主要控矿断裂，其上盘金矿床受NE向断裂构造控制，赋矿围岩为胶东群变质岩，金矿化以含金硫化物石英脉为主。通过首次对招远灵雀山金矿床富金石英脉石英流体包襄体Rb-Sr等时线年龄的测定，获得116±23Ma成矿年龄。从而说明招-平断裂带上盘金矿大规模成矿期发生于早白垩世的构造体系转折期。对富金石英脉石英流体包襄体同位素特征研究表明。该地区成矿热液均以幔源为主，具有与招掖金矿带其它金矿类似的成矿热液系统。由此可以看出招．平断裂带上盘也具有良好的成矿条件。