四、螺纹联接的强度计算螺纹联接通常是采用紧固件。对这些螺纹联接件的螺拴头、螺纹牙、螺母、垫圈等尺寸是不需要进行强度计算的。需要计算部分是螺拴直径或校核危险断面的强度。下面用较简化方法列出最常用的几种计算方法。因绝大多数螺拴联接都是在未受工作载荷前就拧紧螺母,螺拴中产生很大预紧力P_o,这种螺拴联接称为紧联接。另一种情况,在安装时不必把螺母拧紧,工作载荷作用前螺拴若不受力称为松联接。现将常用几种受力情况列表计算如下: Fourth, the strength of the thread connection Thread connection is usually used fasteners. For these threaded coupling bolt, thread teeth, nuts, washers and other dimensions do not need to calculate the intensity. The part to be calculated is the bolt diameter or the strength of the dangerous section. The following simplified method used to list the most commonly used several calculation methods. Because the vast majority of bolted joints are tightened before the work load nut, bolts have a lot of pre-stress P_o, this bolted connection called tight connection. In another case, it is not necessary to tighten the nut during the installation. If the working load is not affected by the force, the bolt should be loosely connected. Several commonly used force list is now calculated as follows: