论文部分内容阅读
我国历次版本锅炉强度计算标准对筒壳中孔排加强计算方法多有变化~([1]),而且限制条件过于严格,表现为:30多年前,制定JB 2194—77水管锅炉受压元件强度计算标准~([2])时,由于担心如果接管(管接头)过厚,则刚度大,会使孔边缘应力增大~([3]),故该标准规定孔桥加强方法只能将原有的(未加强时的)孔桥减弱系数φ_w提高1/3(33%);1979年的“JB2194—77水管锅炉受压元件强度计算标准的补充规定”~([4])在JB 2194—77标准基础上,只允许相邻2孔中存在1个大孔,不允许孔排中全为大孔:
In our country, the calculation standard of boiler strength in the previous editions has many changes to the calculation method of the midline of the shell ([1]), and the restrictive conditions are too strict. The performance is as follows: 30 years ago, the strength of the pressure element of JB 2194-77 When calculating the standard ~ ([2]), there are concerns that if the pipe joint is too thick, the stiffness will increase the stress on the edge of the hole ~ ([3]). Therefore, The original (un-strengthened) bridge attenuation coefficient φ_w is increased by 1/3 (33%); the 1979 Supplementary Provisions of “JB2194-77 Calculation Standards for Strength of Compression Elements of Water Tube Boilers” On the basis of JB 2194-77 standard, only one large hole is allowed in the adjacent two holes, and the big hole is not allowed in the row of holes: