本文關(guān)鍵詞：熱效應(yīng)對(duì)高頻聲振響應(yīng)與疲勞壽命影響研究　出處：《中國科學(xué)技術(shù)大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 統(tǒng)計(jì)能量分析 有限元 耦合損耗因子 熱效應(yīng) 聲振耦合 疲勞壽命

【摘要】：高超聲速飛行器在其巡航和再入階段將會(huì)面臨噪聲載荷、熱載荷、和機(jī)械載荷等復(fù)雜的力學(xué)環(huán)境。噪聲載荷主要是由激波振蕩和湍流邊界層引起的,該噪聲不僅分布的頻段比較寬,而且含有豐富的高頻成份,會(huì)影響飛行器重要儀器設(shè)備的工作精度和可靠性;熱載荷會(huì)導(dǎo)致飛行器的承載力下降,對(duì)結(jié)構(gòu)的固有特性、動(dòng)態(tài)響應(yīng)均會(huì)產(chǎn)生很大的影響。在熱聲載荷的聯(lián)合作用下會(huì)引起結(jié)構(gòu)劇烈聲振響應(yīng),而且可能在快速地交變應(yīng)力作用下,引發(fā)裂紋的萌生、擴(kuò)展,最終導(dǎo)致壁板、蒙皮等結(jié)構(gòu)疲勞破壞。因此考慮熱-聲-振疲勞失效是飛行器設(shè)計(jì)階段必須關(guān)注的問題。本文研究的主要內(nèi)容為典型結(jié)構(gòu)的熱-聲-振耦合及疲勞失效問題。首先采用有限元法探究如何獲取較高精度的耦合損耗因子。接著采用有限元法、統(tǒng)計(jì)能量分析分別研究了熱效應(yīng)對(duì)鋁合金壁板低頻、高頻聲振響應(yīng)以及疲勞壽命的影響。具體內(nèi)容如下:1.典型結(jié)構(gòu)耦合損耗因子計(jì)算及誤差分析采用有限元方法計(jì)算耦合損耗因子并和波法結(jié)果對(duì)比給出有限元方法誤差存在的原因。研究了L型板的邊長、厚度、內(nèi)損耗因子、集中質(zhì)量以及邊界條件對(duì)耦合損耗因子計(jì)算精度的影響,為采用有限元方法計(jì)算出精確耦合損耗因子給出指導(dǎo)。最后研究了預(yù)應(yīng)力對(duì)Y型板耦合損耗因子的影響。2.熱效應(yīng)對(duì)結(jié)構(gòu)低頻聲振響應(yīng)及疲勞壽命的影響采用有限元法分別考察了溫度變化導(dǎo)致結(jié)構(gòu)的剛度(彈性模量和熱應(yīng)力)、材料S-N曲線變化對(duì)鋁合金壁板低頻疲勞壽命的影響規(guī)律,進(jìn)而分析了非均勻溫度場(chǎng)作用下結(jié)構(gòu)的疲勞壽命。3.熱效應(yīng)對(duì)高頻聲振響應(yīng)及疲勞壽命的影響基于統(tǒng)計(jì)能量分析研究了在不同溫度條件下飛行器鋁合金壁板的高頻聲振響應(yīng)及均方應(yīng)力,采用零階矩應(yīng)力譜法獲得危險(xiǎn)點(diǎn)的簡化應(yīng)力功率譜,然后結(jié)合頻域疲勞壽命預(yù)報(bào)方法計(jì)算鋁合金壁板的高頻疲勞壽命。分別研究溫度變化導(dǎo)致結(jié)構(gòu)的剛度、材料S-N曲線變化對(duì)鋁合金壁板高頻疲勞壽命的影響規(guī)律。
[Abstract]:Hypersonic vehicles will face complex mechanical environments such as noise load thermal load and mechanical load during their cruise and reentry. The noise load is mainly caused by shock oscillation and turbulent boundary layer. The noise not only has a wide frequency range, but also contains rich high-frequency components, which will affect the working accuracy and reliability of the important instrument and equipment of the aircraft. The thermal load will lead to the reduction of the bearing capacity of the aircraft, which will have a great impact on the natural characteristics of the structure and the dynamic response, and the combination of the thermoacoustic load will cause the violent acoustic-vibration response of the structure. And it is possible to initiate crack initiation and propagation under the action of fast alternating stress and eventually lead to the wall plate. Therefore, it is necessary to pay attention to the thermal acoustic vibration fatigue failure in the design stage of aircraft. The main contents of this paper are the thermoacoustic vibration coupling and fatigue failure of typical structures. First, the finite element method is used to explore how to obtain the coupling loss factor with high precision. Then, the finite element method is used. The effect of thermal effect on the low frequency of aluminum alloy panel was studied by statistical energy analysis. Effects of high frequency acoustic vibration response and fatigue life. Details are as follows:. 1. The calculation and error analysis of coupling loss factor of typical structures using the finite element method to calculate the coupling loss factor and comparing with the results of the wave method, the reason of the error of the finite element method is given, and the side length of the L-shaped plate is studied. The influence of thickness, internal loss factor, lumped mass and boundary condition on the accuracy of coupling loss factor. Finally, the influence of prestress on coupling loss factor of Y plate is studied. 2. The influence of thermal effect on the low frequency acoustic vibration response and fatigue life of structure is studied. The stiffness of the structure caused by temperature change is investigated by finite element method. Elastic modulus and thermal stress). Influence of material S-N curve change on low frequency fatigue life of aluminum alloy panel. Furthermore, the fatigue life of the structure under the action of inhomogeneous temperature field is analyzed. 3. The effect of thermal effect on the high frequency acoustic vibration response and fatigue life of aircraft aluminum alloy panels under different temperature conditions is studied based on statistical energy analysis. High frequency acoustic vibration response and mean square stress. The simplified stress power spectrum of the dangerous point is obtained by using the zero-order moment stress spectrum method, and then the high-frequency fatigue life of the aluminum alloy panel is calculated by using the frequency-domain fatigue life prediction method. The stiffness of the structure caused by the temperature change is studied respectively. Influence of material S-N curve change on high frequency fatigue life of aluminum alloy panel.
【學(xué)位授予單位】：中國科學(xué)技術(shù)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：V215;O346.2

【相似文獻(xiàn)】

相關(guān)期刊論文 前10條

1 劉兵;何國球;蔣小松;朱e，

本文編號(hào)：1369509