本文選題：扭簧 + 應(yīng)力松弛��； 參考：《西南交通大學(xué)》2013年碩士論文

【摘要】：彈簧及彈性元器件廣泛應(yīng)用于鐵道車輛、飛機、汽車、拖拉機等機械行業(yè),是重要的承載零部件。在其長期服役過程中,主要失效形式有兩種：應(yīng)力松弛和疲勞斷裂。彈簧應(yīng)力松弛和疲勞試驗的常見加載方式主要有拉伸壓縮和彎曲二類,本文針對矩形截面硅錳彈簧鋼進行扭轉(zhuǎn)應(yīng)力松弛試驗研究,同時進行了扭轉(zhuǎn)疲勞試驗。 本文課題特別設(shè)計制作了新型應(yīng)力松弛試驗裝置,基于該裝置,可以研究扭簧在不同溫度下的剪切模量變化規(guī)律、應(yīng)力松弛變化規(guī)律。完成了六組矩形截面扭簧的常溫和高溫應(yīng)力松弛試驗,通過扭矩的變化規(guī)律,總結(jié)出剪切模量的變化規(guī)律及應(yīng)力松弛的變化規(guī)律,建立了硅錳合金彈簧鋼剪切模量關(guān)于溫度和時間的綜合影響函數(shù)和應(yīng)力松弛的曲線方程。 文中通過自由扭轉(zhuǎn)理論計算、ABAQUS有限元模擬計算,分析了扭簧內(nèi)部的應(yīng)力分布規(guī)律,確定了扭轉(zhuǎn)加載下剪應(yīng)力的分布特征,為分析扭簧的應(yīng)力松弛和疲勞性能奠定了基礎(chǔ)。兩種計算方法的相對誤差在2.5%以內(nèi)。 經(jīng)過一年的常溫應(yīng)力松弛試驗,發(fā)現(xiàn)常溫下扭簧應(yīng)力松弛比較緩慢,最大切應(yīng)力幾乎是沿一條水平線上下波動,相對穩(wěn)定,表明硅錳合金彈簧鋼常溫下抗應(yīng)力松弛性能好。經(jīng)過100小時的高溫應(yīng)力松弛試驗,發(fā)現(xiàn)扭簧的剪切模量和最大切應(yīng)力隨溫度的升高而線性降低：在初期的10～20小時內(nèi),剪切模量和最大切應(yīng)力隨時間下降速度比較快,之后下降緩慢；溫度在300℃以內(nèi),剪切模量和最大切應(yīng)力隨時間的增長而緩慢減小；溫度在300℃～400℃間,剪切模量和最大切應(yīng)力隨時間而顯著減小,且減小率隨溫度的增加而線性增大。 三組扭簧常溫下的扭轉(zhuǎn)疲勞試驗結(jié)果表明,疲勞應(yīng)力最大值發(fā)生在扭簧桿件的四條棱邊處,加工過程中表面質(zhì)量和表面光潔度對扭簧的疲勞性能有重要影響,試驗結(jié)果表明扭簧的疲勞性能滿足設(shè)計要求。 本文對硅錳彈簧鋼在常溫、高溫下的扭轉(zhuǎn)應(yīng)力松弛及扭轉(zhuǎn)疲勞的試驗研究結(jié)果,有助于改善扭簧的抗應(yīng)力松弛和抗疲勞性能,具有重要的工程價值和理論意義,并為研究其它形式彈簧的應(yīng)力松弛和疲勞提供了有益參考。
[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，

本文編號：1841078