本文選題：通風盤式制動器 + 熱-結(jié)構(gòu)耦合　； 參考：《華南理工大學》2016年碩士論文

【摘要】：車輛的制動性一直以來都是汽車設(shè)計中最重要的性能指標,它直接影響到交通安全性,而制動器作為車輛制動系統(tǒng)最終的執(zhí)行部件,則直接決定著汽車的制動性。車輛制動時,制動器摩擦副間由于快速的相互摩擦而產(chǎn)生大量的熱,使得制動器的溫度迅速升高,過高的溫度會使得制動器在制動時出現(xiàn)熱衰退現(xiàn)象從而影響汽車的制動性,同時也會導致制動盤表面易出現(xiàn)熱疲勞裂紋而降低其使用壽命。因此對制動器在制動過程中出現(xiàn)的熱-結(jié)構(gòu)耦合現(xiàn)象進行研究和分析,有助于改善汽車的制動性能并提高其使用壽命。本文以某乘用車前輪所使用的通風盤式制動器為研究對象,根據(jù)其實際尺寸建立三維模型,并進行適當?shù)暮喕?隨后將簡化后的三維模型導入有限元分析軟件中建立其熱-結(jié)構(gòu)耦合有限元仿真模型,并根據(jù)整車相關(guān)參數(shù)確定分析所需的邊界條件和載荷。最后對所建立的有限元模型進行仿真計算,并對所獲得的溫度場和應(yīng)力場結(jié)果進行分析。通過對制動盤溫度場的分析可知:制動過程中整個制動盤溫度場的分布并不是呈軸對稱的,在徑向、周向和軸向三個方向上均存在一定的溫差,其中徑向方向最大溫差達到了201℃,軸向方向上最大溫差也達到了178℃,周向方向上的溫差相比徑向和軸向則相對較小,在整個制動過程中不超過25℃,且隨著制動的持續(xù)整個制動盤的溫度場由于內(nèi)部熱傳導的作用而趨于均勻分布;通過對制動盤應(yīng)力場的分析可知:制動時制動盤的應(yīng)力主要以熱應(yīng)力為主,且在制動過程中其變化趨勢與溫度場的變化趨勢基本一致。同時本文還對所研究的通風盤式制動器進行了緊急制動、多次連續(xù)制動和下長坡持續(xù)制動三種工況下的臺架實驗,通過對所得的實驗數(shù)據(jù)進行分析發(fā)現(xiàn)各測溫點的溫度變化趨勢同有限元的分析結(jié)果是一致的,且將緊急制動工況下所測得的徑向5個測溫點的溫度值同有限元的計算值進行對比,其最大誤差僅為14℃,且兩者的相關(guān)系數(shù)均大于0.9,充分證明了本文所建立的通風盤式制動器熱-結(jié)構(gòu)耦合有限元模型的正確性。最后以建立的有限元模型為基礎(chǔ),以制動盤的質(zhì)量和熱疲勞壽命為優(yōu)化目標,對該通風盤式制動器的結(jié)構(gòu)進行多目標優(yōu)化。同時為了降低優(yōu)化成本,通過采用遺傳算法優(yōu)化的神經(jīng)網(wǎng)絡(luò)來構(gòu)建相關(guān)設(shè)計變量與響應(yīng)函數(shù)之間的近似模型,并在此近似模型的基礎(chǔ)上采用基于遺傳算法的多目標優(yōu)化法來對制動器的結(jié)構(gòu)進行優(yōu)化設(shè)計,最后根據(jù)優(yōu)化后的設(shè)計變量重新建立有限元模型并進行仿真計算,其計算結(jié)果證明了優(yōu)化的有效性。
[Abstract]:The braking property of vehicle is always the most important performance index in the automobile design. It directly affects the traffic safety, and the brake, as the final executive part of the vehicle braking system, directly determines the braking property of the vehicle. When the vehicle is braking, a large amount of heat is produced between the brake friction pairs because of the rapid mutual friction, which makes the temperature of the brake rise rapidly, and the excessive temperature will make the brake appear the phenomenon of heat decline during braking, thus affecting the braking performance of the car. At the same time, it will lead to thermal fatigue crack on the brake disc surface and reduce its service life. Therefore, the study and analysis of the thermo-structural coupling phenomenon in the braking process is helpful to improve the braking performance and prolong the service life of the automobile. In this paper, the ventilation disc brake used in the front wheel of a passenger car is taken as the research object. According to its actual size, a three-dimensional model is established and properly simplified. Then, the simplified 3D model is introduced into the finite element analysis software to establish the thermal-structural coupling finite element simulation model, and the boundary conditions and loads for the analysis are determined according to the relevant parameters of the whole vehicle. Finally, the finite element model is simulated, and the results of temperature field and stress field are analyzed. Through the analysis of the temperature field of the brake disc, it can be seen that the distribution of the temperature field of the whole brake disc is not axisymmetric during the braking process, and there is a certain temperature difference in the radial, circumferential and axial directions. The maximum temperature difference in the radial direction is 201 鈩，

本文編號：1994880