本文選題：復(fù)合材料層合板 + 分層理論��； 參考：《南昌航空大學(xué)》2015年碩士論文

【摘要】：復(fù)合材料層合板結(jié)構(gòu)因其比模量大,比強度高,抗疲勞性能好,可設(shè)計性和低噪聲性,被廣泛應(yīng)用于航空航天、船舶汽車制造等工業(yè)領(lǐng)域。復(fù)合材料層合板結(jié)構(gòu)在實際工程運用中難免受到外界激勵產(chǎn)生受迫振動,并向周圍輻射聲,產(chǎn)生噪聲污染。而層合板結(jié)構(gòu)振動一般處于中低頻段,其聲輻射特性與自身結(jié)構(gòu)參數(shù)、激勵位置及激勵頻率有關(guān)。因此,研究層合板結(jié)構(gòu)在中低頻時的聲振特性,對噪聲控制具有重要意義和實際價值。本文將以復(fù)合材料層合板結(jié)構(gòu)為對象,對其受迫振動及聲輻射性能展開研究。首先,對復(fù)合材料層合板的振動特性進行理論推導(dǎo)。本文采用分層理論結(jié)合有限元的方法,計算層合板結(jié)構(gòu)的各階固有頻率、結(jié)構(gòu)振型以及在外激勵下的動態(tài)響應(yīng)。通過數(shù)值模擬與參考文獻中的解析解及其它理論計算結(jié)果進行對比,驗證分層理論計算固有頻率的精確性。其次,基于分層理論計算層合板結(jié)構(gòu)的聲輻射模態(tài)伴隨系數(shù)及輻射聲功率,并在單點及兩點激勵下分別對層合板的聲輻射特性進行研究。分析了截斷模態(tài)數(shù)目、層合板的鋪設(shè)角度、激勵點位置、激勵頻率對聲輻射模態(tài)系數(shù)幅值及輻射聲功率的影響。結(jié)果表明,層合板結(jié)構(gòu)的鋪設(shè)角度、激勵位置及激勵頻率對層合板的聲振特性有不同程度上的影響。最后,基于遺傳算法對層合板結(jié)構(gòu)聲輻射的最小化進行優(yōu)化分析。在理論上,計算聲輻射模態(tài)伴隨系數(shù)需要整個板表面的振動速度信息,但在實際工程中難以實現(xiàn)且意義不大。由于聲輻射模態(tài)存在正交性,文中通過測量有限點的速度,利用最小二乘法來獲取前N階聲輻射模態(tài)伴隨系數(shù)近似值,進而對聲輻射最小化進行分析。并基于遺傳算法對有限測量點進行優(yōu)化,以實現(xiàn)控制聲輻射的最小化。
[Abstract]:Because of its large specific modulus, high specific strength, good fatigue resistance, good design and low noise, composite laminates are widely used in aerospace, shipbuilding and other industrial fields. The composite laminates are difficult to avoid forced vibration from external excitation in the practical application of the composite laminates, and produce noise from the surrounding area and produce noise. The vibration of laminates is generally in the middle and low frequency segments, and the acoustic radiation characteristics are related to their own structural parameters, the excitation position and the excitation frequency. Therefore, the study of the acoustic vibration characteristics of the laminate structure at low and low frequencies is of great significance and practical value for the noise control. The vibration and acoustic radiation performance are studied. First, the vibration characteristics of composite laminates are theoretically derived. In this paper, the hierarchical theory and finite element method are used to calculate the natural frequencies of each order of the laminate structure, the structure mode and the dynamic response under the external excitation. The theoretical calculation results are compared to verify the accuracy of the inherent frequency of the stratified theory. Secondly, based on the stratification theory, the acoustic radiation mode adjoint coefficient and radiation power are calculated, and the acoustic radiation characteristics of the laminates are studied under single and two excitation. The number of truncated modes and the laminates are analyzed. The effect of the laying angle, the position of the excitation point and the excitation frequency on the amplitude of acoustic radiation modal coefficient and the radiation sound power. The results show that the laying angle of the laminate structure, the excitation position and the excitation frequency have different influence on the acoustic vibration characteristics of the laminate. Finally, the optimization of the acoustic radiation of the laminate structure is optimized based on the genetic algorithm. In theory, the calculation of the adjoint coefficient of acoustic radiation mode needs the information of the vibration velocity of the whole surface of the plate, but it is difficult to realize in the actual project and has little significance. Because of the orthogonality of the acoustic radiation mode, the approximate value of the adjoint coefficient of the former N order acoustic radiation mode is obtained by measuring the velocity of the finite point in the paper. The minimum acoustic radiation is analyzed, and the limited measurement points are optimized based on genetic algorithm to minimize the acoustic radiation.

【學(xué)位授予單位】：南昌航空大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TB33;TB53

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本文編號：1895951