汽车车身NVH特性分析与结构优化设计
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1.1 课题研究的背景和意义 ........................................................................................................... 1 1.2 国内外研究现状 ....................................................................................................................... 2 1.2.1 国外 NVH 特性研究现状.................................................................................................. 2 1.2.2 国内 NVH 特性研究现状.................................................................................................. 3 1.2.3 响应面法研究现状 ............................................................................................................ 4 1.3 本文研究主要内容 ................................................................................................................... 4
A Thesis Submitted to Chongqing University in Partial Fulfillment of the Requirement for Professional Degree
By Hui Fei
Supervised by Prof. Zheng Ling Pluralistic Supervised by senior Engineer Suyu Specialty: ME （Automobile Engineering Field）
III
重庆大学硕士学位论文
IV
目
录
目
录
中文摘要.......................................................................................................................................... I 英文摘要....................................................................................................................................... III 1 绪 论 ...................................................................................................................................... 1
I
重庆大学硕士学位论文
II
英文摘要
ABSTRACT
With the improvement of requirement for vehicle comfort, improving NVH characteristics of vehicle is the principal means to upgrade the vehicle and improve the competitiveness. Based on a SUV, the finite element model of car body ,acoustic cavity and acoustical-structure interaction has been built. The characteristic of NVH has been analyzed, including BIW (body-in-white modal), vehicle modal, acoustic cavity modal, the torsion and bedding stiffness of BIW, acoustical-structure interaction NTF, acoustical-structure interaction VTF and acoustical-structure interaction IPI. Using the volume and one order torsion and bend frequency as the objective function and constraints, the optimization of improving the body frequency has been done by using response surface method and optistruct. The results as follow： ①The finite element models of car body, car and acoustic cavity have been built, the modal of car body, car and acoustic cavity has been analyzed. With the analysis one order torsion and bend frequency are get as 33.4Hz and 44.3Hz, which is the basis of the optimization of car body. ②Based on the actual driving situation of car boy, the torsion and bedding stiffness have been analyzed. Compared to the car boy stiffness of the car, the result is reasonable. The curves of torsion stiffness and bedding stiffness have been gotten. Which indicates the stiffness of car body is uniformly distributed. ③The finite element model of acoustical-structure interaction has been built by DIFF. the characteristic of NTF、VTF and IPI have been analyzed, with different stimulations the peaks of sound pressure, vibration and dynamic stiffness have been get, which indicate the characteristic of NVH is reasonable. ④The experimental matrix has been get by Latin hypercube design, and the response surface models of car volume, one order torsion stiffness and one order bedding stiffness have been built by using response surface method. The optimization of genetic algorithm is used to optimize the thickness of plate, the result shows the quality has decrease 22.8kg, the torsion stiffness has increased2Hz and the bedding stiffness has increased1.5Hz. Key words: NVH, modal, response surface method, structure optimization
College of Vehicle Engineering of Chongqing University, Chongqing, China May, 2015
中文摘要
摘
要
随着用户对汽车舒适性的要求越来越高，提高汽车 NVH 性能是国内汽车企业 提高其市场竞争力及其产品升级的重要方向之一。 本文针对某企业 SUV 项目车型， 采用有限元方法，建立了车身、声腔及声固耦合有限元模型，对其 NVH 特性进行 了分析，主要包括白车身模态、整车模态、声腔模态、白车身扭转及弯曲刚度、 声固耦合 NTF、声固耦合 VTF、声固耦合 IPI，并以车身体积为目标函数，整车一 阶扭转、弯曲频率等为约束条件，以响应面法对车身壁板厚度进行了优化，以达 到车身轻量化的目的。论文主要内容及结论如下： ①建立白车身、整车、声腔有限元模型，计算了白车身模态、整车模态及声 腔模态，得到了整车的一阶扭转频率 33.4Hz 和一阶弯曲频率 44.3Hz，为车身结构 优化提供了依据。 ②根据车身实际行驶情况，计算了白车身的弯曲刚度和扭转刚度，与项目车 型车身刚度要求进行比较，车身刚度符合要求，同时绘制了弯曲刚度和扭转刚度 变化曲线，两曲线连续光滑无突变，说明车身结构刚度分布均匀，无应力集中现 象。 ③以 DIFF 方式建立声固耦合有限元模型，分析了该车型的 NTF、VTF、IPI 特性，获得了在不同的激励下车身响应点的声压峰值、振动峰值、动刚度峰值， 验证该车型 NVH 特性的合理性。 ④采用拉丁超立方试验设计方法，将部分灵敏度大的车身板件厚度作为数据 样本点，计算响应矩阵，以多项式响应面法，建立车身体积、一阶扭转频率、一 阶弯曲频率的响应面模型，采用遗传算法优化板件厚度，优化结果表明，在质量 减少 22.8kg 的同时，一阶扭转频率和一阶弯曲频率分别提高 2Hz 和 1.5Hz。 关键词：汽车 NVH，模态，响应面法，结构优化
2 有限元分析理论与车内噪声产生机理 ................................................................. 7
2.1 有限元法概述 ........................................................................................................................... 7 2.1.1 有限元法的发展及基本思想 ............................................................................................ 7 2.1.2 有限元法的基本步骤 ......................................................................................................... 7 2.1.3 有限元法在汽车工程中的应用 ........................................................................................ 9 2.2 声学有限元法 ......................................................................................................................... 10 2.3 车内噪声产生机理 ................................................................................................................. 10 2.3.1 结构噪声 .......................................................................................................................... 10 2.3.2 空气噪声 .......................................................................................................................... 11 2.3.3 声腔共鸣 .......................................................................................................................... 11 2.4 Hyperworks 简介 .................................................................................................................... 12 2.4.1 Hypermesh 介绍 ................................................................................................................ 12 2.4.2 Optistruct 介绍 .................................................................................................................. 13 2.4.3 Hyperstudy 介绍................................................................................................................ 13 2.5 本章小结 ................................................................................................................................. 13
汽车车身 NVH 特性分析与结构优化设计
重庆大学硕士学位论文
（专业学位）
学生姓名：惠 指导教师：郑 兼职导师：苏
飞 玲 宇 教 高 授 工
学位类别：工程硕士（车辆工程领域）
Fra Baidu bibliotek
重庆大学汽车工程学院
二 O 一五年五月
NVH Performance Analysis and Structural Optimization Design of Vehicle Body
A Thesis Submitted to Chongqing University in Partial Fulfillment of the Requirement for Professional Degree
By Hui Fei
Supervised by Prof. Zheng Ling Pluralistic Supervised by senior Engineer Suyu Specialty: ME （Automobile Engineering Field）
III
重庆大学硕士学位论文
IV
目
录
目
录
中文摘要.......................................................................................................................................... I 英文摘要....................................................................................................................................... III 1 绪 论 ...................................................................................................................................... 1
I
重庆大学硕士学位论文
II
英文摘要
ABSTRACT
With the improvement of requirement for vehicle comfort, improving NVH characteristics of vehicle is the principal means to upgrade the vehicle and improve the competitiveness. Based on a SUV, the finite element model of car body ,acoustic cavity and acoustical-structure interaction has been built. The characteristic of NVH has been analyzed, including BIW (body-in-white modal), vehicle modal, acoustic cavity modal, the torsion and bedding stiffness of BIW, acoustical-structure interaction NTF, acoustical-structure interaction VTF and acoustical-structure interaction IPI. Using the volume and one order torsion and bend frequency as the objective function and constraints, the optimization of improving the body frequency has been done by using response surface method and optistruct. The results as follow： ①The finite element models of car body, car and acoustic cavity have been built, the modal of car body, car and acoustic cavity has been analyzed. With the analysis one order torsion and bend frequency are get as 33.4Hz and 44.3Hz, which is the basis of the optimization of car body. ②Based on the actual driving situation of car boy, the torsion and bedding stiffness have been analyzed. Compared to the car boy stiffness of the car, the result is reasonable. The curves of torsion stiffness and bedding stiffness have been gotten. Which indicates the stiffness of car body is uniformly distributed. ③The finite element model of acoustical-structure interaction has been built by DIFF. the characteristic of NTF、VTF and IPI have been analyzed, with different stimulations the peaks of sound pressure, vibration and dynamic stiffness have been get, which indicate the characteristic of NVH is reasonable. ④The experimental matrix has been get by Latin hypercube design, and the response surface models of car volume, one order torsion stiffness and one order bedding stiffness have been built by using response surface method. The optimization of genetic algorithm is used to optimize the thickness of plate, the result shows the quality has decrease 22.8kg, the torsion stiffness has increased2Hz and the bedding stiffness has increased1.5Hz. Key words: NVH, modal, response surface method, structure optimization
College of Vehicle Engineering of Chongqing University, Chongqing, China May, 2015
中文摘要
摘
要
随着用户对汽车舒适性的要求越来越高，提高汽车 NVH 性能是国内汽车企业 提高其市场竞争力及其产品升级的重要方向之一。 本文针对某企业 SUV 项目车型， 采用有限元方法，建立了车身、声腔及声固耦合有限元模型，对其 NVH 特性进行 了分析，主要包括白车身模态、整车模态、声腔模态、白车身扭转及弯曲刚度、 声固耦合 NTF、声固耦合 VTF、声固耦合 IPI，并以车身体积为目标函数，整车一 阶扭转、弯曲频率等为约束条件，以响应面法对车身壁板厚度进行了优化，以达 到车身轻量化的目的。论文主要内容及结论如下： ①建立白车身、整车、声腔有限元模型，计算了白车身模态、整车模态及声 腔模态，得到了整车的一阶扭转频率 33.4Hz 和一阶弯曲频率 44.3Hz，为车身结构 优化提供了依据。 ②根据车身实际行驶情况，计算了白车身的弯曲刚度和扭转刚度，与项目车 型车身刚度要求进行比较，车身刚度符合要求，同时绘制了弯曲刚度和扭转刚度 变化曲线，两曲线连续光滑无突变，说明车身结构刚度分布均匀，无应力集中现 象。 ③以 DIFF 方式建立声固耦合有限元模型，分析了该车型的 NTF、VTF、IPI 特性，获得了在不同的激励下车身响应点的声压峰值、振动峰值、动刚度峰值， 验证该车型 NVH 特性的合理性。 ④采用拉丁超立方试验设计方法，将部分灵敏度大的车身板件厚度作为数据 样本点，计算响应矩阵，以多项式响应面法，建立车身体积、一阶扭转频率、一 阶弯曲频率的响应面模型，采用遗传算法优化板件厚度，优化结果表明，在质量 减少 22.8kg 的同时，一阶扭转频率和一阶弯曲频率分别提高 2Hz 和 1.5Hz。 关键词：汽车 NVH，模态，响应面法，结构优化
2 有限元分析理论与车内噪声产生机理 ................................................................. 7
2.1 有限元法概述 ........................................................................................................................... 7 2.1.1 有限元法的发展及基本思想 ............................................................................................ 7 2.1.2 有限元法的基本步骤 ......................................................................................................... 7 2.1.3 有限元法在汽车工程中的应用 ........................................................................................ 9 2.2 声学有限元法 ......................................................................................................................... 10 2.3 车内噪声产生机理 ................................................................................................................. 10 2.3.1 结构噪声 .......................................................................................................................... 10 2.3.2 空气噪声 .......................................................................................................................... 11 2.3.3 声腔共鸣 .......................................................................................................................... 11 2.4 Hyperworks 简介 .................................................................................................................... 12 2.4.1 Hypermesh 介绍 ................................................................................................................ 12 2.4.2 Optistruct 介绍 .................................................................................................................. 13 2.4.3 Hyperstudy 介绍................................................................................................................ 13 2.5 本章小结 ................................................................................................................................. 13
汽车车身 NVH 特性分析与结构优化设计
重庆大学硕士学位论文
（专业学位）
学生姓名：惠 指导教师：郑 兼职导师：苏
飞 玲 宇 教 高 授 工
学位类别：工程硕士（车辆工程领域）
Fra Baidu bibliotek
重庆大学汽车工程学院
二 O 一五年五月
NVH Performance Analysis and Structural Optimization Design of Vehicle Body