Graduation Design (Dissertation) of Wuhan University of Technology

Cockpit Design and Human Factors for Driving Simulation System

College (Department): International Education

Specialty amp; class: Vehicle Engineering gj1302

Student name: Han Xia

Tutor: Lin Xu

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Abstract

In this paper, SCANIA-P380 is used as a prototype vehicle to develop a reverse matching compound air suspension. Under the normal circumstances, the full air suspension of independent suspension and four bar linkage mechanism is more complex than the full air suspension with spring guide arm or semi air suspension. The former have large number of parts and the hinge point and also the cost of maintenance is high and the cost is high. Most of them are higher from 50% to 100% than the suspension which uses leaf spring as the leading arm, and some even increased by 200%. The combined air suspension has the advantages of simple structure and be convenient to reconstruct. For the truck or bus chassis with longeron or segmented stringers, the structure arrangement of compound air suspension is relatively simple and the force is reasonable. The conventional front-axle beam and rear bridges that match the leaf spring suspension, especially the pre forged I-beam and the forged rear axle housing requires little modification and can be fitted directly with this composite air suspension. According to the existing conditions of the model, select the type of air damper and absorber; select plate spring; check the strength of the plate spring; Combined with the influence of the airbag on the stiffness of the whole elastic system, calculate the deflection frequency and the result is compared with the design requirement. Then design leaf spring support, absorber support and so on. Finally, CAE strength analysis of key parts is carried out.

Key words: air suspension, leaf spring leading arm , air spring , CATIA , CAE

catalogue

Abstract 3

Key words 3

catalogue 4

Chapter 1 Introduction 5

1.1 The Introduction of Combined Air Suspension 5

1.2 Overview 6

Chapter 2 Input of Design 7

2.1 Target Parameter Input 7

2.2 Boundary Conditions Input 7

Chapter 3 Design and Calculation 8

3.1 Design-related Technical Parameters Air Suspension 8

3.2 Hard Dots Arrangement 9

3.3 Preliminary Selection of The Airbag 9

3.4 Preliminary Selection of The Damper 11

3.4.1 Damper selection 12

Chapter 4 Part Design 14

4.1 Leaf Spring 14

4.2 Leaf Spring Support 14

4.3 Damper Bracket and Support 15

4.4 Airbag Stent 15

Chapter 5 Computing of Suspension Performance 16

5.1 Stiffness of leaf spring 16

5.2 Suspension Offset Frequency Calculation 18

5.2.1Total Stiffness of Suspension 18

5.2.2Air Suspension Offset Frequency: 18

5.3 Stiffness Roll Angle 18

5.3.1Angular Stiffness of The Air Spring 19

5.4 Strength check of the leaf spring 19

Chapter 6 Strength CAE Analysis of Key Parts 28

6.1 An Overview of Finite Element Analysis 28

6.2 Boundary Conditions 30

6.3 Key parts stress analysis 32

6.3.1 Stress analysis of damper support and the stand 32

6.3.2 Stress analysis of leaf spring support and taper leaf spring under different conditions 34

6.3.3 Results improvement 36

Summary and Prospect 36

Thank 36

Reference 37

Chapter 1 Introduction

1.1 The Introduction of Combined Air Suspension

Suspension is used to convey the role of the wheel and the frame between the force and the twist of the body. The elastic components buffer displacement and the damping element play the role of reducing vibration to ensure that the car can run smoothly.

Air suspension has been developed for a century since the mid-nineteenth century which is the birth of air suspension. It experienced "pneumatic spring - air suspension → airbag composite suspension → semi-active air suspension → central charge and discharge suspension and other changes in the type. To the fifties of the twentieth century was used in trucks, buses, cars and railway cars. At present, almost all foreign high-class bus use the air suspension. The proportion of Heavy truck using air suspension has reached more than 80%, the application of light vehicles using air suspension is also rapidly rising. Some of the cars are also gradually installed using air suspension, in some special vehicles (such as shockproof requirements of the high instrument car, ambulance, special military vehicles and the requirements of the container truck, etc.), the use of air suspension is almost the only choice.

In the domestic air suspension is still in its infancy, most of the domestic air suspension are composite air suspension, the real active all-air suspension is mostly imported from the luxury sedan such as: SUV models Porsche Cayenne, 911, Mercedes ML350, 500,550, Land Rover's Range Rover, Car Audi A8, Mercedes-Benz S600 and so on. The reasons for this situation, on the one hand, are the domestic technical level cannot be compared with developed countries such as Europe and the United States and the manufacture of air suspension has many difficulties, mostly in the trial or experimental research stage , lack of adequate technical support. On the other hand, because the actual consumption level is not high at home, and the manufacturing cost of the whole air suspension is much higher than the consumption budget of the ordinary people. Therefore, the whole air suspension is only used in the high-end passenger car. The air suspension is actually similar to a luxury.