型材拉弯加工工艺的弯扭失稳计算

　　型材拉弯加工工艺的弯扭失稳计算根据拉弯与压弯构件弯扭失稳的相似性,推导出弯扭失稳时拉力与弯矩的理论相关公式,并采用有限元法对公式进行了验证;参考现行钢结构设计规范提出了设计用的拉力弯矩相关公式,与欧洲规范EC3的公式进行了比较.结果表明,在弹性阶段,双轴对称截面的计算公式更加接近有限元计算结果,而对于单轴对称截面和T形截面,EC3的公式有时偏于不安全.

　　An analytical and numeric al analysis on flexural-torsional buckling of members in combined ben ding and axial tension is carried out.The interaction relations of a xial force and bending moment are established for members with diffe rent uniaxial-symmetrical cross-sec tion,and confirmed by finite eleme nt analysis.At last,interaction eq uation of axial load and bending l oad is proposed for practical desi gn.A comparison is made between the proposed formulae and those of Eur ocode 3.

　　我国混凝土结构设计规范对截面受压区有预应力筋的正截面承载力计算公式的简化处理存在安全隐患。根据应变协调原则，提出了纯弯、压弯和拉弯三种受力模式通用的正截面承载力修正计算公式。利用纤维截面分析软件XTRACT验证了修正公式的正确性和计算精度。
　　There is a security risk in the simplified calculation formula of normal section bearing capacity of prestressed tendons in the section compressive zone in the concrete structure design codes of China Based on the principle of strain coordination,a universal modified calculation formula of normal section bearing capacity for three mechanical modes of pure bending compressive bending and tension bending is proposed.The analysis software XTRACT of fiber section is used to validate the correctness and calculation accuracy of the modified formula.
　　很多工程项目已不再局限于我国自行设讹自行施工，一些国际知名的设计公司、建筑公司参与国内重大项目建设的例子比比皆是。这就要求我们在熟知本国规范的同时，还要了解国外的相关规范，特别是要明晰不同规范之间的异同。基于上述考虑，本文拟从基本构件在简单荷载一拉弯、压弯作用下的相关计算规定出发。天津盛达鸿业科技有限公司经过多年科技创新，建筑拉弯与工业拉弯的贯通结合，形成了独特的拉弯体系。