在现代液压机设计理论中，全预紧组合框架结构是目前液压机本体结构的首选形式。拉杆预紧力的大小直接影响整个压机结构的稳定性。通过应用力学分析和数值模拟，对不考虑压机横梁变形和考虑压机横梁变形两种情况下预应力结构的工作过程进行分析，分别给出预应力机架在预紧过程中和加载后立柱和拉杆变形的理论计算公式；同时推导出加载后机架残余预紧力的理论计算公式，并与有限元计算结果进行对比。为反映压机工作时拉杆预紧程度对立柱残余压力的影响，给出立柱剩余预紧系数的概念及其计算公式并给出取值范围，为预应力结构液压机的设计计算提供新的理论计算方法。

In the modern design theory on the hydraulic press, reloaded composite frame becomes preferred structure of hydraulic press. The pre-tension force directly affects the stability of the structure of whole press. Through the analysis of the pre-stressed frame’s working process with and without deformation of beam by using the mechanical analysis and numerical simulation, vertical post and tension rod deformation calculation formulas are derived; At the same time, the theory formula of frame residual pre-tightening force after loading is given, and be compared with finite element calculation results. In order to reflect the tension rod preload degree effect on the vertical post’s residual stress, residual pre-tightening coefficient definition and calculation formula are given, and its scope is also given. New method for the force parameters of pre-stressed structure is provided.