1、PDF外文：http:/ 6020 字 出处： International Journal of Automotive Technology, 2009, 10(3): 321-328 毕 业 设 计（论 文） 外 文 参 考 资 料 及 译 文 译文题目： STRUCTURAL OPTIMIZATION OF A CIRCUMFERENTIAL FRICTION DISK BRAKE WITH CO
2、NSIDERATION OF THERMOELASTIC INSTABILITY 圆周摩擦的盘式制动器 结构优化（考虑热弹不稳定性） 学生姓名： 学 号： &
3、nbsp; 专 业： 机械设计制造及其自动化（现代汽车 技术 ） 所在学院： 机电工程学院 指导教师：
4、; 职 称： 2010 年 3 月 20 日 STRUCTURAL OPTIMIZATI
5、ON OF A CIRCUMFERENTIAL FRICTION DISK BRAKE WITH CONSIDERATION OF THERMOELASTIC INSTABILITY B.-C. SONG1) and K.-H. LEE2)* 1)Research Engineer, R&D Center, NEXEN TIRE Corporation, Yangsan-si, Gyeongnam 626-230, Korea 2)Department of Mechanical Engineering, Dong-A University, Busan 604
6、-714, Korea ABSTRACTThis research suggests a new disk brake design using circumferential friction on the disk of a front-wheel-drive passenger car. The paper compares mechanical performance between the conventional and suggested disk brakes under dynamic braking conditions. Thermoelastic
7、 instability is considered in simulation of the test condition. An optimization technique using a metamodel is introduced to minimize the weight of the suggested disk brake. To achieve this goal, the response defined in the optimization formulation is expressed in a mathematically explicit for
8、m with respect to the design variables by using a kriging surrogate model, resulting in a simple optimization problem. Then, the simulated annealing algorithm is utilized to find the global optimum. The design results obtained by the kriging method are compared with those obtained from ANSYS a
9、nalysis. KEY WORDS : Circumferential friction disk brake, Ventilated disk brake, Structural optimization, Thermoelastic instability, Kriging 1. INTRODUCTION Recently developed vehicle components aim for a light-weight design to achieve high fuel efficiency and vehicle performance.
10、The fact that certain components are developed with target weights in units of grams during the prototype design stage (Lee and Kang, 2007) underscores the importance of lightweight design. However, the current disk brake has a limit for possible weight reduction. This study introduces a new approac
11、h using a circumferential friction disk brake for active weight reduction. In order to investigate the thermal characteristics, the circumferential disk brake is compared with the ventilated disk brake that is currently used in the mid-size front-wheel drive car made by the Z Company. When developin
12、g an automobile disk brake, vibration and noise are the most important elements considered among the design requirements for mechanical performance. However, most vibrations and forms of noise are generated by resonance with the car body or chassis (Hwang and Park, 2005), and it may therefore be mea
13、ningless to investigate the related performance of the brake components as separate from the car body and chassis. In general, the first natural frequency of a four-door sedan is more than 30 Hz； thus, a design improvement in the brake component alone can eliminate or minimize the noise generated fr
14、om vibrations lower than 30 Hz. The judder is divided into cold judder and hot judder, where hot judder is known to be caused by the thermoelastic instability (TEI) phenomenon (Choi and Lee, 2003； Chung et al., 2005). It has been reported that reducing the thermal deformation is an effective way to
15、reduce hot judder (Koji et al., 2004). When the brake is applied during high-speed driving, a large contact pressure is generated on parts of the frictional surface due to unequal contact pressure between the pad and disk, such that the heat generated on certain parts is relatively higher than in ot
16、her locations. This unequal contact pressure causes the local temperature to rise such that it, in turn, generates additional increases in local contact pressure. This phenomenon, known as the TEI phenomenon, is repeated and progresses, eventually leading to generation of “hot spots”. In order to an
17、alyze the TEI, a coupled field composed of both the thermal and contact problems should be considered. Recent research related to ventilated disk brakes have focused on finite element analysis (FEA) or other experimental approaches that include consideration of the TEI (Kao et al., 2000； Oscar et al
18、., 2002； Lee and Brooks,2003； Choi and Lee, 2003； Koji et al., 2004； Hwang et al.,2005； Chung et al., 2005； Cho et al., 2007). In contrast, only a few research works have focused their studies on structural optimization of the disk brake (Lee et al., 2000； Lee et al., 2001). In the reference (Lee et
19、 al., 2000), the optimum shape of a disk brake rotor was obtained by using the gradient based optimization algorithm, in which the judder-induced deformation was minimized, satisfying the target weight goal. Meanwhile, in the reference (Lee et al.2001), the RSM (response surface method) was adopted
20、to determine the optimum shape of the disk section. However, both works only considered a thermal stress determined from the heat transfer analysis, without including the TEI effect. This study dedicates special attention to application of an approximated optimization process of the lightweight desi
21、gn of a circumferential friction disk brake, including consideration of the TEI phenomenon. To reduce computing time in the optimization process and to find a global optimum, an in-house program called the Kriging-SA is developed. The metamodels, called kriging methods (Guinta and Watson, 1998； Fang
22、 et al., 2006； Lee and Kang, 2007),are adopted to approximate true responses such as weight,stress, and natural frequency. The commercial FE software ANSYS is utilized for the coupled analysis, and the optimum results obtained by the suggested method are compared with the optimizer built into ANSYS.
23、 2. THERMOELASTIC CONTACT ANALYSIS OF DISK BRAKE 2.1. Thermal Analysis and Thermoelastic Contact Analysis 2.1.1. Heat transfer and elastic problems The second fade test in test procedure FMVSS 105-75,applied to the hydraulic and electric brake systems, specifies the following conditions.
24、 A vehicle traveling at a speed of 97 km/h reduces its speed at 0.6 g for 4.57 seconds, accelerates for 25 seconds until speed is back to 97 km/h, and then continues with the same speed for 5.43 seconds. This process is shown in Figure 1 (Taesung S&E, 2006). Each cycle lasts 35 seconds and a total of 15 cycles are performed.
