【摘要】：針對涂層結(jié)合界面剛度在非破壞條件下難以精確測量的問題,提出了一種超聲檢測特征參量表征剛度系數(shù)的方法。利用聲波在n層各向同性介質(zhì)中的反射、透射原理,結(jié)合界面的彈簧模型,建立了多層介質(zhì)界面剛度系數(shù)的超聲檢測數(shù)學(xué)模型�；w選用鋼、鑄鐵、鋁合金,表面選用不同噴涂工藝得到的Al2O3陶瓷涂層,獲得了不同界面剛度系數(shù)的超聲反射頻譜。仿真結(jié)果表明:分離界面和理想界面時,諧振頻率都具有周期性,但周期大小不同;弱結(jié)合界面時,隨著界面的剛度系數(shù)逐漸增加,諧振頻率逐漸增多,這些諧振頻率均向高頻方向移動。與頻率較高處相比,頻率較低處的諧振頻率隨著剛度系數(shù)的增加向高頻移動的速度更快。因此建立了第一個諧振頻率與剛度系數(shù)之間的關(guān)系。在同一剛度系數(shù)下,由諧振頻率與材料的特性阻抗關(guān)系獲得如下規(guī)律:當(dāng)涂層材料不變時,諧振頻率隨著基體特性阻抗的增大而增大;當(dāng)基體材料不變時,諧振頻率隨著涂層特性阻抗的增大而減小。給出了以指數(shù)函數(shù)形式擬合的剛度系數(shù)與諧振頻率的變化曲線。通過對該指數(shù)函數(shù)參數(shù)與材料特性阻抗之間關(guān)系的分析,獲得了弱界面時諧振頻率與剛度系數(shù)和材料特性阻抗三者之間的函數(shù)表達(dá)式。該方法為涂層復(fù)合材料弱界面的超聲檢測提供了理論支持。
[Abstract]:In order to solve the problem that it is difficult to accurately measure the interface stiffness of the coating under the condition of non-failure, a method to characterize the stiffness coefficient by ultrasonic testing characteristic parameters is proposed. Based on the principle of reflection and transmission of sound waves in n-layer isotropic medium and the spring model of interface, a mathematical model of ultrasonic testing for the stiffness coefficient of interface of multi-layer medium is established. Steel, cast iron, aluminum alloy and Al2O3 ceramic coating with different spraying process were used to obtain the ultrasonic reflection spectrum of different interface stiffness coefficients. The simulation results show that the resonant frequency is periodic when the interface is separated from the ideal interface, but the period is different. When the interface is weakly bonded, the resonant frequency increases with the increase of the stiffness coefficient of the interface, and these resonant frequencies all move to the high frequency direction. Compared with the higher frequency, the resonant frequency at the lower frequency moves faster to the high frequency with the increase of the stiffness coefficient. Therefore, the relationship between the first resonant frequency and the stiffness coefficient is established. Under the same stiffness coefficient, the relationship between the resonant frequency and the characteristic impedance of the material is obtained as follows: when the coating material is constant, the resonant frequency increases with the increase of the substrate characteristic impedance; When the substrate material is invariant, the resonant frequency decreases with the increase of the characteristic impedance of the coating. The variation curve of stiffness coefficient and resonance frequency is given in the form of exponential function. Based on the analysis of the relationship between the parameters of the exponential function and the material characteristic impedance, the functional expressions of resonance frequency, stiffness coefficient and material characteristic impedance at weak interface are obtained. This method provides theoretical support for ultrasonic detection of weak interface of coated composites.
【作者單位】： 景德鎮(zhèn)陶瓷大學(xué)機械電子工程學(xué)院;
【基金】：國家自然科學(xué)基金(51305184;51565020) 江西省教育廳科技項目(GJJ150925)
【分類號】：TG174.453
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本文編號：2345094