本文選題：裂紋 + 懸臂梁��； 參考：《振動與沖擊》2017年08期

【摘要】：基于扭轉(zhuǎn)彈簧模型和修正Paris公式,提出了一種在不同外界溫度下含初始裂紋懸臂梁的疲勞壽命估算方法。在模態(tài)分析過程中,通過彈性模量引入溫度模塊,利用扭轉(zhuǎn)彈簧等效該裂紋,將懸臂梁轉(zhuǎn)化為由扭轉(zhuǎn)彈簧聯(lián)接的兩段彈性梁;推導(dǎo)出不同溫度下含裂紋梁固有振型的特征方程,分析溫度和裂紋幾何參數(shù)對裂紋梁固有頻率的影響。在疲勞壽命分析過程中,利用復(fù)彈性模量引入阻尼損耗因子,基于修正Paris方程和同步分析法,考慮裂紋梁振動與疲勞裂紋擴(kuò)展的相互作用,分析溫度、阻尼和懸臂梁根部區(qū)域裂紋幾何參數(shù)對裂紋梁疲勞壽命的影響。結(jié)果表明:隨著裂紋相對位置的減小以及裂紋相對深度的增大,裂紋懸臂梁的固有頻率和疲勞壽命則逐漸降低;而外界溫度的升高也會導(dǎo)致裂紋懸臂梁固有頻率和疲勞壽命的降低;同時(shí)隨著阻尼損耗因子的逐漸增大,裂紋懸臂梁的疲勞壽命也會逐漸增加。
[Abstract]:Based on torsional spring model and modified Paris formula, a fatigue life estimation method for cantilever beams with initial cracks at different external temperatures is proposed. In the process of modal analysis, the temperature module is introduced into the elastic modulus and the torsional spring is used to equivalent the crack. The cantilever beam is transformed into a two-segment elastic beam connected by torsional spring, and the characteristic equation of the inherent mode of the beam with cracks at different temperatures is derived. The influence of temperature and geometric parameters of crack on the natural frequency of cracked beam is analyzed. In the process of fatigue life analysis, the damping loss factor is introduced by using complex modulus of elasticity. Based on the modified Paris equation and synchronous analysis method, the interaction between vibration and fatigue crack propagation of cracked beam is considered, and the temperature is analyzed. The effects of damping and geometric parameters of crack at the root of cantilever beam on fatigue life of cracked beam. The results show that the natural frequency and fatigue life of cracked cantilever gradually decrease with the decrease of the relative position of crack and the increase of relative depth of crack. The increase of external temperature also leads to the reduction of natural frequency and fatigue life of cracked cantilever beam, and the fatigue life of cracked cantilever beam increases gradually with the increase of damping loss factor.
【作者單位】： 南京航空航天大學(xué)機(jī)械結(jié)構(gòu)力學(xué)及控制國家重點(diǎn)實(shí)驗(yàn)室;
【基金】：江蘇高校優(yōu)勢學(xué)科建設(shè)工程基金資助
【分類號】：TB123

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本文編號：1828731