Sharif Digital Repository

The level and character of noise emitted by exhaust system has significant effect on the overall acoustic performance of vehicle powertrain and sound quality which is received by occupants. In addition to meeting aforementioned objective, the exhaust system must meet exterior noise regulation which is ordered by governments. In this study, acoustic performance of the vehicle exhaust system is investigated. Numerical simulation is applied for this aim that is the fastest and the most economical method in early design stages of vehicle development process. Thickness optimum design is performed in order to improve acoustic performance of exhaust system. Robust parameter design, based on Taguchi... 

Squeak and rattle (S&R) noises are important in-cabin sources of annoyance for occupants. Originally, S&R is generated as a result of colliding and slamming of car's trim and body structure which in turn occurs because of the dynamic displacements of components excited by road and power-train. Squeak noise is interpreted as periodic stick and slip phenomena in the contact boundary of two neighbor surfaces. While rattle noise is the emitted noise when adjacent surfaces collide and impact. Squeak noise takes place at low frequency while rattle phenomenon happens in high-frequency range, even though the excitation sources (road and power-train line) works in low frequency range. In practice,... 

Owing to the expensive and time-consuming nature of durability experiments, finite element based durability analysis is quite prevalent in the automotive industry. Numerical fatigue life analyses are typically divided into two different categories, the quasi-static methods which are faster and the dynamic methods which are more accurate. The aim of this paper is to compare the inertia relief and modal dynamic approaches in terms of formulation, accuracy and computation time. The chosen case study is the fatigue life of the vehicle body which is considered the main load-bearing component in a vehicle. By utilizing multi-body dynamics model and driving the vehicle on different standardized...