本文選題：非線性超聲 + 疲勞損傷　； 參考：《振動(dòng)與沖擊》2017年21期

【摘要】：為了有效地分析金屬疲勞損傷過程中裂紋擴(kuò)展與演化的特征,提出利用混沌分形理論對蘊(yùn)含疲勞裂紋擴(kuò)展規(guī)律的超聲非線性輸出信號進(jìn)行分析,用Lyapunov指數(shù)、K熵、關(guān)聯(lián)維數(shù)等特征量對金屬疲勞損傷過程的特性進(jìn)行表征和評價(jià)。采用RITEC公司的RAM-5000系統(tǒng)獲得具有不同疲勞損傷程度試件的超聲非線性輸出信號,計(jì)算疲勞過程中的Lyapunov指數(shù)、K熵、關(guān)聯(lián)維數(shù)。分析結(jié)果表明金屬疲勞損傷過程中超聲非線性輸出信號具有混沌特性;Lyapunov指數(shù)、關(guān)聯(lián)維數(shù)、K熵等特征值隨疲勞循環(huán)次數(shù)單調(diào)遞增,當(dāng)宏觀裂紋出現(xiàn)后趨于飽和,說明疲勞損傷過程中試件內(nèi)部的復(fù)雜程度和混沌特征逐漸增強(qiáng);由疲勞過程中微裂紋的演化規(guī)律可知,混沌分形特征值可以有效地表征試件在疲勞過程中裂紋的變化規(guī)律和群體性行為。因此混沌分形理論可以有效地分析金屬疲勞損傷過程中裂紋擴(kuò)展與演化的特征,根據(jù)混沌分形特征值—疲勞循環(huán)次數(shù)的關(guān)系,為試件的疲勞壽命預(yù)測提供了一種新的分析方法。
[Abstract]:In order to effectively analyze the characteristics of crack propagation and evolution in the process of metal fatigue damage, the chaotic fractal theory is used to analyze the ultrasonic nonlinear output signals containing the law of fatigue crack growth. The characteristics of the fatigue damage process of metal are characterized and evaluated with Lyapunov, K entropy and correlation dimension. The RIT is used to evaluate the characteristics of the fatigue damage process. The RAM-5000 system of EC company obtains the ultrasonic nonlinear output signal with different fatigue damage test parts, and calculates the Lyapunov index, the K entropy and the correlation dimension in the fatigue process. The analysis results show that the ultrasonic nonlinear output signal has chaotic characteristics in the process of metal fatigue damage, and the eigenvalues of the Lyapunov exponent, correlation dimension and K entropy are with fatigue. The cycle times are monotonically increasing, and when the macro cracks appear to be saturated, the complexity and chaotic characteristics of the specimens are gradually enhanced during the fatigue damage process. It is known from the evolution law of the micro cracks in the fatigue process that the chaotic fractal characteristic value can effectively characterize the change law and mass behavior of the cracks in the fatigue process. Therefore, the chaotic fractal theory can effectively analyze the characteristics of crack propagation and evolution in the process of metal fatigue damage. According to the relationship of the chaotic fractal characteristic value - fatigue cycle times, a new analysis method is provided for the fatigue life prediction of the specimen.
【作者單位】： 廣西大學(xué)輕工與食品工程學(xué)院;廣西大學(xué)機(jī)械工程學(xué)院;
【基金】：國家自然科學(xué)基金(51365006;51445013)
【分類號】：TG115.58

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