工程结构及其计算中常见的各种类型的曲线多属初等函数的图象,近似计算时,可以在限定的区间内将一曲线之函数表达式以另一曲线来替代,这种替代从数学上严格地讲并不属于相似,但为简便仍称其曲线为相似曲线。利用相似曲线,在满足计算精度的条件下,往往可以简化运算过程。对于变截面构件的变位及静不定结构的内力分析,若采用相似曲线,多半可以直接积分得出规律性的表达式。 The various types of curves commonly used in engineering structures and their calculations are mostly images of elementary functions. In approximate calculation, the function expression of a curve can be replaced by another curve within a defined interval. This substitution is from mathematics. Strictly speaking, it does not belong to similarity, but for the sake of simplicity, the curve is still called a similar curve. Using the similarity curve, the calculation process can be simplified by satisfying the calculation accuracy. For the analysis of the internal forces of the displacement and statically indeterminate structures with variable cross-sections, if similar curves are used, most of them can be directly integrated to derive regular expressions.