外文翻譯--研究汽車盤式制動(dòng)器熱和力學(xué)性能的優(yōu)化設(shè)計(jì)

1、<p>　　研究汽車盤式制動(dòng)器熱和力學(xué)性能的優(yōu)化設(shè)計(jì) </p><p>　　摘要: 運(yùn)用ABAQUS軟件,對(duì)轎車盤式制動(dòng)器在不同車速、不同摩擦片材料下的模擬仿真,</p><p>　　據(jù)不同工況下的計(jì)算結(jié)果得出磨擦片熱分布規(guī)律,最后提出盤式制動(dòng)器的改進(jìn)設(shè)計(jì)方案。</p><p>　　關(guān)鍵詞:盤式制動(dòng)器;摩擦熱;有限單元 </p><p&

2、gt;　　制動(dòng)系統(tǒng)是汽車最重要的系統(tǒng)。如果制動(dòng)失敗,結(jié)果是很可怕的。制動(dòng)系統(tǒng)實(shí)際上是能量轉(zhuǎn)換裝置,將汽車的動(dòng)能轉(zhuǎn)換為熱能。典型的制動(dòng)系統(tǒng)包括盤式制動(dòng)器和鼓式制動(dòng)器。</p><p>　　汽車上使用的是兩個(gè)完整的獨(dú)立的制動(dòng)系統(tǒng)。他們是行車制動(dòng)和駐車制動(dòng)。行車制動(dòng)在減速，停車或正常行駛時(shí)駐車起作用。他們通過(guò)司機(jī)踩踏和放松制動(dòng)踏板來(lái)實(shí)現(xiàn)。制動(dòng)器的主要目的是在無(wú)人看管是保持車輛平穩(wěn)停止。駐車制動(dòng)是在拉起手剎或制動(dòng)腳踏板時(shí)

3、由機(jī)械操縱的。 </p><p>　　盤式制動(dòng)器因?yàn)楫a(chǎn)生的熱和停車時(shí)的機(jī)械載荷很容易引起噪聲和震動(dòng)問(wèn)題。這種噪音,震動(dòng)和NVH現(xiàn)象不僅不舒服，而且很危險(xiǎn)。此外，由于熱摩擦產(chǎn)生的溫度變化，導(dǎo)致制動(dòng)盤和轉(zhuǎn)子之間摩擦轉(zhuǎn)變和墊襯材料機(jī)械壓力系數(shù)變化。壓力變化是一種非線性現(xiàn)象，正如摩擦現(xiàn)象是一般非線性耦合問(wèn)題。特別是在汽車盤式制動(dòng)系統(tǒng)中熱抖動(dòng)噪聲振動(dòng)是非線性耦合問(wèn)題。這些現(xiàn)象也共享核心設(shè)計(jì)等因素,如轉(zhuǎn)子和襯里之間的壓力分布

4、，轉(zhuǎn)子的形狀和剛度,空氣排氣口組成，散熱的性能和摩擦的變化。因此，應(yīng)在考慮和分析抖動(dòng)和噪聲的同時(shí)優(yōu)化盤式制動(dòng)器的設(shè)計(jì)。</p><p>　　當(dāng)出現(xiàn)嚴(yán)重的摩擦加熱超過(guò)一定的轉(zhuǎn)子和墊之間的滑動(dòng)速度，臨界速度時(shí)，會(huì)發(fā)生熱彈性形變。一些關(guān)鍵的因素，如臨界速度，外部溫度，運(yùn)動(dòng)時(shí)閥板厚度變化可能會(huì)導(dǎo)致制動(dòng)盤的熱變形。此外,頻繁制動(dòng)也能誘導(dǎo)制動(dòng)器的高熱。這些情況導(dǎo)致較高的熱變形和熱點(diǎn)，這是熱顫動(dòng)的原因之一。一個(gè)相對(duì)高強(qiáng)度，低頻

5、率的震動(dòng)，應(yīng)該是從盤式制動(dòng)系統(tǒng)通過(guò)樞紐，懸浮驅(qū)動(dòng)，方向盤，剎車踏板和地板。此外，頻繁和高溫?zé)狳c(diǎn)結(jié)合，很容易導(dǎo)致物質(zhì)損失，其中包括制動(dòng)盤表面裂紋的產(chǎn)生。該熱點(diǎn)現(xiàn)象也稱為摩擦性熱彈性不穩(wěn)定，被Barber首次發(fā)現(xiàn)并應(yīng)用到摩擦系統(tǒng)。Lee和Barber解決了假設(shè)隨著時(shí)間推移，在溫度和應(yīng)力場(chǎng)的擾動(dòng)成倍增加的TEI 問(wèn)題。他們表明，不穩(wěn)定的發(fā)病總是由一個(gè)反對(duì)稱的對(duì)應(yīng)圓周屈曲變形模式導(dǎo)致熱點(diǎn)在制動(dòng)盤兩側(cè)交替。此外，使用汽車盤式模型，他們發(fā)現(xiàn)，由兩個(gè)

6、半空間模型計(jì)算的臨街轉(zhuǎn)速高出實(shí)驗(yàn)。Yeo和Barber衍生出的有限元攝動(dòng)方法，即線性方程組是利用時(shí)間獲取與指數(shù)變化擾動(dòng)分隔的變量的解決方案制定。他們利用有限元分析解決了盤式制動(dòng)器和離合器的TEI問(wèn)題。他們解釋說(shuō)，主波長(zhǎng)和臨界速度并非主要受三維效果的影響，被很好的預(yù)測(cè)一個(gè)二維（平面）的</p><p>　　盡管努力減少或消除噪聲的發(fā)生，噪聲呈現(xiàn)出另一種整個(gè)汽車行業(yè)的主要制動(dòng)器的NVH問(wèn)題。這是一種當(dāng)司機(jī)減速或低速是

7、產(chǎn)生的高頻率的噪聲。因?yàn)樗邱詈系闹苿?dòng)系統(tǒng)，噪聲不容易解決。因此，噪聲問(wèn)題應(yīng)該仔細(xì)評(píng)估。有兩種利用有限元分析的方法來(lái)模擬和分析盤式制動(dòng)器的噪聲問(wèn)題，一是非線性瞬態(tài)模擬或動(dòng)態(tài)瞬態(tài)分析，另一種是線性或非線性穩(wěn)定分析。這兩種方法各有優(yōu)缺點(diǎn)，要準(zhǔn)確的分析和預(yù)測(cè)噪聲，都需要在轉(zhuǎn)子和其他制動(dòng)元件固有特性研究方面有良好的相關(guān)性。目前有很多以通過(guò)實(shí)驗(yàn)方法和仿真的研究。Dessouki等把噪聲分為卡鉗托架誘導(dǎo)（2-6.5千赫），墊誘導(dǎo)（4-11千赫）和轉(zhuǎn)

8、子誘導(dǎo)（7-16千赫）幾類。通過(guò)FEA，Junior等研究了某些操作參數(shù)如摩擦系數(shù)，材料性能，磨損以及絕緣體對(duì)盤式制動(dòng)系統(tǒng)的影響。Fieldhouse根據(jù)一些具體的噪聲頻率研究了墊的形狀，并解釋說(shuō)動(dòng)態(tài)的不穩(wěn)定行能被預(yù)測(cè)。Kung等使用復(fù)雜的特征值問(wèn)題的方法研究了低頻噪聲，并報(bào)告說(shuō)這是種有效的分析方法。Dihau和Jiang利用有限元分析研究耦合模式解決了復(fù)雜的特征值問(wèn)題。Triches等采用模態(tài)分析技術(shù)選擇適當(dāng)?shù)闹苿?dòng)閘以減少剎車噪聲。

9、Kung等</p><p>　　在這項(xiàng)研究中，通過(guò)三個(gè)轉(zhuǎn)子標(biāo)本對(duì)TEI和機(jī)械穩(wěn)定性進(jìn)行了研究。制動(dòng)測(cè)功機(jī)和高速紅外攝像機(jī)被用于TEI分析。圓錐角是根據(jù)制動(dòng)盤的形狀確定，角度的改變能改變制動(dòng)盤和墊之間的接觸壓力分布，是改變壓力分布的主要因素。壓力分布影響著熱穩(wěn)定性和機(jī)械穩(wěn)定性。首先，熱變形和圓錐角的在恒定溫度下的變化是計(jì)算所考慮的幾何轉(zhuǎn)子。焊盤的壓力分布按照卡尺增壓類型計(jì)算，并將結(jié)果和TEI進(jìn)行分析和比較。臨界轉(zhuǎn)速

10、的分析結(jié)果通過(guò)商業(yè)軟件HOTSPOTTER獲得。將從實(shí)驗(yàn)和分析方法得到的結(jié)果進(jìn)行比較和分析。要進(jìn)行復(fù)雜的特征值分析，自然頻率和模式是由制動(dòng)盤和墊片的模態(tài)試驗(yàn)和有限元分析得出的。通過(guò)有限元分析，按照制動(dòng)盤厚度，襯砌弧長(zhǎng)度和增壓類型來(lái)決定不穩(wěn)定耦合模式并估計(jì)不穩(wěn)定的機(jī)械力學(xué)性能差異來(lái)解決復(fù)雜的特征值問(wèn)題。最后，利用這些成果為優(yōu)化熱性能和力學(xué)性能進(jìn)行評(píng)估和分析。</p><p>　　盤式制動(dòng)器轉(zhuǎn)子部分由頂部，頸部，氣孔

11、和內(nèi)外側(cè)板組成。摩擦熱被認(rèn)為是轉(zhuǎn)子的主要熱源，其產(chǎn)生是由于內(nèi)外側(cè)板和剎車片之間的接觸摩擦。如熱傳導(dǎo)，熱對(duì)流過(guò)程，和輻射產(chǎn)生的轉(zhuǎn)子溫度梯度，并導(dǎo)致熱變形。此外，內(nèi)外側(cè)的密度層不僅在接觸表面的局部熱集中，由于密度方向傳到速度的差異，還影響轉(zhuǎn)子剛度，特別是在外平面。這三個(gè)幾何模型是基本模型，2t-0t模型和2t-2t模型。所有這3個(gè)轉(zhuǎn)子直徑均為254毫米。在2t-0t轉(zhuǎn)子模型中，外側(cè)的鋼板厚度減少了2毫米。類似的，在2t-2t轉(zhuǎn)子模型中，內(nèi)側(cè)

12、和外側(cè)的鋼板厚度均減少了2毫米。</p><p>　　轉(zhuǎn)子的熱變形是由于摩擦生熱產(chǎn)生的制動(dòng)盤和焊盤之間的非均勻壓力分布。轉(zhuǎn)子之間的接觸壓力和高墊影響TEI和機(jī)械不穩(wěn)定性。摩擦熱源是法向力，摩擦系數(shù)和相對(duì)速度的一個(gè)表現(xiàn)。制動(dòng)盤和墊之間眼里分布產(chǎn)生的偏心是由于錐角偏轉(zhuǎn)，DTV和加壓性卡鉗及可能導(dǎo)致的快速非均勻發(fā)熱。在這些因素中，可以對(duì)轉(zhuǎn)子的形狀設(shè)計(jì)適當(dāng)降低圓錐角。對(duì)此進(jìn)行熱變形和壓力分布的有限元分析。</p&g

13、t;<p>　　圓錐角沒(méi)有固定值由于在行駛時(shí)轉(zhuǎn)子的溫度分布變化。通常，通過(guò)實(shí)驗(yàn)和有限元分析調(diào)節(jié)制動(dòng)工況來(lái)實(shí)現(xiàn)圓錐角，熱應(yīng)力和熱容量。然而，在這項(xiàng)研究中，為了通過(guò)轉(zhuǎn)子厚度有限元分析來(lái)尋找相應(yīng)的圓錐角假定了一個(gè)均勻100°C的溫度。通過(guò)仿真結(jié)果，對(duì)熱性能進(jìn)行評(píng)價(jià)并按照內(nèi)外側(cè)的厚度差別進(jìn)行分析。根據(jù)TEI和按照墊形狀和增壓條件的機(jī)械不穩(wěn)定性對(duì)壓力分布進(jìn)行非線性有限元分析。為了產(chǎn)生一個(gè)墊上對(duì)應(yīng)一點(diǎn)到兩點(diǎn)加壓卡鉗的壓力分布

14、，應(yīng)用一個(gè)反映卡鉗活塞形狀的壓力條件。靜態(tài)和動(dòng)態(tài)條件下都適用。在靜態(tài)條件下，旋轉(zhuǎn)速度為零，靜壓力為1.5MPa。在動(dòng)態(tài)條件下，轉(zhuǎn)子轉(zhuǎn)速為10轉(zhuǎn)/分，壓力大小為1.5MPa，摩擦系數(shù)為0.4。在TEI分析，該墊的壓力分布可用于預(yù)測(cè)有效壓力和有效內(nèi)襯弧長(zhǎng)，它反映了熱點(diǎn)數(shù)目和臨界速度。熱點(diǎn)數(shù)目和臨界速度與內(nèi)襯弧長(zhǎng)密切相關(guān)。因此，利用有效壓力和有效內(nèi)襯弧長(zhǎng)的概念可以使TEI模型更加準(zhǔn)確。使用有限元分析套件ABAQUS 6.6對(duì)熱變形和結(jié)構(gòu)分析來(lái)

15、計(jì)算出圓錐角和壓力分布。</p><p>　　圓錐角是根據(jù)制動(dòng)盤厚度并通過(guò)對(duì)熱結(jié)構(gòu)有限元分析來(lái)計(jì)算的。模擬結(jié)果顯示了再100°C時(shí)圓錐角和內(nèi)測(cè)板的偏轉(zhuǎn)。圓錐角的相對(duì)比率是轉(zhuǎn)子標(biāo)準(zhǔn)錐角和基準(zhǔn)的比。結(jié)果表明，圓錐角有一個(gè)相對(duì)較低的絕對(duì)值。然而，由于恒定溫度邊界條件需要根據(jù)轉(zhuǎn)子形狀實(shí)現(xiàn)一個(gè)相對(duì)熱變形差，所以相對(duì)圓錐角差值比絕對(duì)圓錐角更重要。根據(jù)轉(zhuǎn)子的基本標(biāo)準(zhǔn)，2t-0t模型顯示了最小的圓錐角比例。這一結(jié)果表明

16、，頸部的截面差異很大的作用于導(dǎo)致變形差的幾何約束。因此，內(nèi)外側(cè)厚度差異不僅顯著的影響結(jié)構(gòu)特征，而且引起熱變形。在實(shí)際的汽車上，在嚴(yán)重的熱負(fù)荷和機(jī)械負(fù)荷下，轉(zhuǎn)子邊緣的撓度與由于DTV和跳動(dòng)產(chǎn)生的非均勻壓力下相比相對(duì)值較高。因此，它不能夠被忽視。雖然DTV和跳動(dòng)還增加了制動(dòng)盤和焊盤之間的局部壓力，他們不依賴與轉(zhuǎn)子橫截面的形狀。因此，為了制動(dòng)盤的優(yōu)化設(shè)計(jì)考慮熱變形和轉(zhuǎn)子錐角以及熱容量是必要的。</p><p>　　熱

17、力耦合和熱抖動(dòng)過(guò)程造成制動(dòng)盤表面產(chǎn)生熱點(diǎn)，不穩(wěn)定的摩擦生熱，熱彈性形變和彈性接觸?？偹苤紫?，司機(jī)會(huì)感到如方向盤，踏板的抖動(dòng)，在較高頻率內(nèi)伴隨著震動(dòng)聲音。然后，制動(dòng)抖動(dòng)主要影響舒適性，或有可能當(dāng)一個(gè)沒(méi)有經(jīng)驗(yàn)的司機(jī)第一次面對(duì)時(shí)導(dǎo)致了錯(cuò)誤的反應(yīng)會(huì)影響行車安全，最后，熱抖動(dòng)會(huì)造成制動(dòng)盤永久性的扭曲或開(kāi)裂。高溫也可能導(dǎo)致剎車過(guò)度磨損，尤其是在出現(xiàn)熱點(diǎn)的位置。實(shí)驗(yàn)技術(shù)在熱力耦合調(diào)查中發(fā)揮主要作用。在捷克克大學(xué)最新技術(shù)研究中心，Pilsen，對(duì)

18、在實(shí)驗(yàn)室和實(shí)際情況下的熱力耦合進(jìn)行實(shí)驗(yàn)研究。其目的是弄清各種物理參數(shù)的影響，包括起源，發(fā)展和熱力耦合在宏觀和微觀的后果。其結(jié)果將被應(yīng)用到設(shè)計(jì)人員的結(jié)構(gòu)建議中，并轉(zhuǎn)化為對(duì)制動(dòng)系統(tǒng)和技術(shù)用戶的技術(shù)建議。 </p><p>　　A study of thermal and mechanical behaviour for the optimal design of automotive disc brakes <

19、/p><p>　　Abstract:With finite element analys is software ABAQUS , the work statements of car disk brake in different speeds and different materials are analysis . Then according to the results of heat is tribut

20、ions in the different statements , the rules of heat distributions are given . Finally , improvement methods about designing disk brake are presented.</p><p>　　Keywords : Disk brake ; Friction heat ;Finite e

21、lement method</p><p>　　The braking system is the most important system in cars. If the brakes fail, the result can be disastrous. Brakes are actually energy conversion devices, which convert the kinetic ener

22、gy (momentum) of the vehicle into thermal energy (heat). The typical brake system consists of disk brakes in front and either disk or drum brakes.</p><p>　　Two complete independent braking systems are used o

23、n the car. They are the service brake and the parking brake. The service brake acts to slow, stop, or hold the vehicle during normal driving. They are foot-operated by the driver depressing and releasing the brake pedal.

24、 The primary purpose of the brake is to hold the vehicle stationary while it is unattended. The parking brake is mechanically operated by when a separate parking brake foot pedal or hand lever is set.</p><p>

25、;　　Disc brake systems are prone to noise and vibration problems arising because of the severe thermal and mechanical loads applied to stop the vehicle. This noise, vibration, and harshness (NVH) phenomenon is not only un

26、comfortable but also dangerous. In addition thermal variations, which occur by frictional heat, generate mechanical pressure variation between the disc and lining owing to a change in the friction coefficient between the

27、 rotor and pad lining materials. The pressure variation is a no</p><p>　　When severe friction heating occurs over a certain sliding speed (critical speed) between the rotor and pad, thermoelastic distortion

28、occurs. Some critical factors such as the critical speed, external temperature, run-out, and disc thickness variation (DTV) can cause thermal distortion of the brake disc. In addition, frequent braking also induces high

29、thermal deformation in the brake disc. These conditions cause relatively high thermal distortion and hot spots, which are one of the origins of h</p><p>　　Despite efforts to reduce or eliminate its occurren

30、ce, squeal noise presents another major brake NVH problem throughout the automotive industry .It is a high-frequency noise produced when the driver decelerates and/or stops the vehicle at a low speed. Because it is coup

31、led to the brake system, squeal cannot be solved easily. Therefore, the squeal problem should be evaluated carefully. There are two main approaches to simulate and analyse disc brake squeal using FEA methods: one is non

32、-linear t</p><p>　　In this study, TEI and mechanical instability are investigated in accordance with three rotor specimens: lining arc lengths of one-pot pressurization and two-caliper pressurization types (

33、one-pot and two-pot types). A brake dynamometer and a high-speed infrared camera are used for the TEI analysis. The coning angle is formed in accordance with brake disc shapes such as hat and neck, and this angle alters

34、the contact pressure distribution between the disc and the pad, and is one of the main facto</p><p>　　The disc brake rotor consists of a hat section, neck section, air vent, and outboard and inboard plates.

35、Frictional heat, which occurs because of contact between the inboard and outboard plates and the brake pad, is assumed to be the main heat source of the rotor. Thermal processes such as heat conduction, convection, and r

36、adiation generate temperature gradients on the rotor and cause thermal deformation. In addition, the inboard and outboard thicknesses govern not only the local heat concentrat</p><p>　　The thermal deformatio

37、n of the rotor due to frictional heating produces a non-uniform pressure distribution between the disc and pad. The contact pressure between the rotor and pad highly affects the TEI and the mechanical instability. The fr

38、ictional heat source is a function of the normal force, friction coefficient, and relative velocity. This eccentric pressure distribution between the disc and pad arises because of the coning angle, run-out, DTV, and pre

39、ssurization type of caliper and can le</p><p>　　The coning angle has no fixed value because the temperature distribution of the rotor varies during driving. Generally, experiment and FEA through regulated br

40、aking condition are performed to achieve coning angles, thermal stress, and thermal capacity [25,28,29]. However, in this study, a uniform temperature distribution of 100 °C is assumed in the thermal FEA for finding

41、 the relative coning angle according to the rotor thicknesses. Through the simulation results, thermal behaviours were evaluat</p><p>　　The coning angles in accordance with the thicknesses of the brake disc

42、were calculated by a thermal structural FEA. Table 1 shows the simulation results for the coning angle and deflection of the inboard plate at 100 °C. The relative ratio of coning angle is the ratio between the conin

43、g angle of the rotor specimen and the base rotor. The results show that the coning angle has a relatively low absolute value. However, the relative coning angle difference is more important than the absolute coning</p

44、><p>　　A uniform pressure distribution between the rotor and lining is one of the most important factors in the optimal design. A uniform pressure distribution implies larger contact area, broader contact heat

45、 generation, and stiffer lining, which can result in hot spots and more noise in the brake system. A uniform pressure distribution can also cause brake NVH problems. However, to obtain highly efficient braking force unde

46、r stability, a uniform pressure distribution is more stable than a relatively</p><p>　　Thermomechanical coupling or thermal judder processes result in hot spots on the urface of a brake disc and unstable int

47、eraction between frictional heating,thermoelastic istortion , and elastic contact. It is well known, first, that the driver feels brake udder as vibrations in the steering wheel, brake pedal, and the floor (i