硅锰合金弹簧钢力学性能研究

发布时间：2018-05-04 02:04

  本文选题：扭簧 + 应力松弛　； 参考：《西南交通大学》2013年硕士论文

【摘要】：弹簧及弹性元器件广泛应用于铁道车辆、飞机、汽车、拖拉机等机械行业,是重要的承载零部件。在其长期服役过程中,主要失效形式有两种：应力松弛和疲劳断裂。弹簧应力松弛和疲劳试验的常见加载方式主要有拉伸压缩和弯曲二类,本文针对矩形截面硅锰弹簧钢进行扭转应力松弛试验研究,同时进行了扭转疲劳试验。 本文课题特别设计制作了新型应力松弛试验装置,基于该装置,可以研究扭簧在不同温度下的剪切模量变化规律、应力松弛变化规律。完成了六组矩形截面扭簧的常温和高温应力松弛试验,通过扭矩的变化规律,总结出剪切模量的变化规律及应力松弛的变化规律,建立了硅锰合金弹簧钢剪切模量关于温度和时间的综合影响函数和应力松弛的曲线方程。 文中通过自由扭转理论计算、ABAQUS有限元模拟计算,分析了扭簧内部的应力分布规律,确定了扭转加载下剪应力的分布特征,为分析扭簧的应力松弛和疲劳性能奠定了基础。两种计算方法的相对误差在2.5%以内。 经过一年的常温应力松弛试验,发现常温下扭簧应力松弛比较缓慢,最大切应力几乎是沿一条水平线上下波动,相对稳定,表明硅锰合金弹簧钢常温下抗应力松弛性能好。经过100小时的高温应力松弛试验,发现扭簧的剪切模量和最大切应力随温度的升高而线性降低：在初期的10～20小时内,剪切模量和最大切应力随时间下降速度比较快,之后下降缓慢；温度在300℃以内,剪切模量和最大切应力随时间的增长而缓慢减小；温度在300℃～400℃间,剪切模量和最大切应力随时间而显著减小,且减小率随温度的增加而线性增大。 三组扭簧常温下的扭转疲劳试验结果表明,疲劳应力最大值发生在扭簧杆件的四条棱边处,加工过程中表面质量和表面光洁度对扭簧的疲劳性能有重要影响,试验结果表明扭簧的疲劳性能满足设计要求。 本文对硅锰弹簧钢在常温、高温下的扭转应力松弛及扭转疲劳的试验研究结果,有助于改善扭簧的抗应力松弛和抗疲劳性能,具有重要的工程价值和理论意义,并为研究其它形式弹簧的应力松弛和疲劳提供了有益参考。
[Abstract]:Spring and elastic components are widely used in railway vehicles, aircraft, automobiles, tractors and other mechanical industries, is an important bearing parts. In the long service, there are two main failure forms: stress relaxation and fatigue fracture. The main loading modes of spring stress relaxation and fatigue test are tensile compression and bending. In this paper, torsional stress relaxation test and torsional fatigue test are carried out for rectangular silicon manganese spring steel. In this paper, a new type of stress relaxation test device is specially designed and manufactured. Based on this device, the variation of shear modulus and stress relaxation of torsion spring at different temperatures can be studied. The stress relaxation tests of six groups of rectangular torsion springs at room temperature and high temperature have been completed. The variation of shear modulus and stress relaxation have been summarized through the variation of torque. The comprehensive influence function of shear modulus of Si-Mn alloy spring steel on temperature and time and the curve equation of stress relaxation are established. In this paper, the stress distribution in torsion spring is analyzed by using Abaqus finite element method, and the characteristics of shear stress distribution under torsional loading are determined, which lays a foundation for the analysis of stress relaxation and fatigue behavior of torsion spring. The relative error of the two methods is within 2.5%. After one year's stress relaxation test at room temperature, it is found that the stress relaxation of torsion spring is slow at room temperature, and the maximum shear stress is almost fluctuating up and down a horizontal line, which is relatively stable, which indicates that the stress relaxation resistance of Si-Mn alloy spring steel is good at room temperature. After 100 hours of high temperature stress relaxation test, it is found that the shear modulus and maximum shear stress of the torsion spring decrease linearly with the increase of temperature. The shear modulus and maximum shear stress decrease slowly with the increase of time, and the shear modulus and maximum shear stress decrease significantly with time when the temperature is 300 鈩，

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