大底脚螺纹抽钉芯杆强度计算方法研究

Research on Strength Calculation Method for Screws of Blind Bolted

因具有连接强度高、对复合材料损伤小、可实现单面连接、断口齐平免打磨等优点,大底脚螺纹抽钉被广泛应用于航空航天领域中复材结构的连接。复材用大底脚螺纹抽钉目前主要依赖于进口,尚未实现自主研发。本文针对某结构类型大底脚螺纹抽钉芯杆强度的计算方法,首先介绍了此结构大底脚螺纹抽钉的安装过程,并对其进行受力分析。然后基于材料力学第四强度理论(冯·米塞斯屈服准则)建立芯杆关键位置处(断颈槽和第一牙螺纹)最大应力的表达式,通过建立具有两段不同UNJF螺纹的芯杆有限元模型计算出表达式中的应力集中系数。最终分析得到各因素对芯杆关键位置处最大应力的影响规律。通过以上建立的大底脚螺纹抽钉芯杆强度计算方法,达到提升大底脚螺纹抽钉连接可靠性和经济效益的目的。

Due to the advantages of high connection strength,little damage to composite materials,single-sided connection and smooth fracture without grinding,blind bolted rivets are widely used for fastening composite structures in the aerospace field.At present,blind bolted rivets are mainly imported from foreign countries,lacking of stable manufacturing methods domestically.This paper focused on the strength calculation method for a certain type of blind bolted rivets,firstly introduced its installation process and analyzed mechanical property.Then based on the Fourth failure criteria(Von mises yield criterion),expressions for the maximum stress at key positions of the screw(fracture groove and first thread)were established.By establishing a finite element model of the screw with two different UNJF threads,the stress concentration coefficients in expressions were calculated.Finally,the influence of various factors on the maximum stress at critical positions was analyzed.This research would be meaningful and valuable in improving the connection reliability and economic efficiency through this established strength calculation method.