Search Results

The job of a suspension system is to maximize the friction between the tires and the road surface, to provide steering stability with good handling and to act as a cushioning device to ensure the comfort of the driver and passengers. The suspension system also protects the vehicle and any cargo or luggage from damage and wear. Commonly the strength of these suspension systems is evaluated by endurance trials on field or Rig testing which are time consuming and costly. On the other hand, virtual testing methods for strength and stiffness evaluation provide useful information early in the design cycle and save significant time and cost. However, the virtual method also needs validation, which can be achieved by physical co-relations (via rig tests). A study has been done to predict the behavior of Leaf Spring Suspensions entirely through the FEA (Finite Element Analysis) route and correlating those results with physical test.

Most popular practice for analyzing the Subsystem failures in commercial vehicles is physical testing. These physical tests are carried out by three tests; Endurance testing, Accelerated Endurance Testing and Rig test simulation. All the three methods are costly and repetitive iterations of these tests is not economical. Therefore, in our organization, we established a method in virtual domain in order to reduce the repetitive iterations and also reduction in time consumed per iteration. General practice in our organization for Finite Element Analysis (FEA) calculation was inclusive of Model preparation, Transient analysis using Nastran. The results from the Transient analysis are used for performing fatigue analysis in fatigue software. In this process, Transient analysis and Model preparation are very much time consuming processes. Model preparation cannot be reduced, but to reduce the transient analysis time, we established a method in frequency domain (vibrational fatigue) [1].

Tractor-semitrailers make up large proportion of heavy commercial vehicles, handling stability of tractor-semitrailers is critical to driving safety. Handling behavior of Tractor-semitrailers is complex and depends on various parameters. This paper presents a mathematical approach & multi body dynamics (MBD) simulation based study to gain an insight as to, how changes to different parameters of the articulated vehicle affect it’s handling behavior and thus to obtain an optimized design in terms of vehicle handling. A Full vehicle multi body dynamic model is created and steady state cornering maneuvers are performed on simulation tool MSC ADAMS/View for calculating understeer gradient using constant radius test method. Various parameters affecting understeer gradient are identified, studied and their relative effect on understeer gradient is measured. These critical parameters were then optimized using MSC ADAMS/View tool to achieve the desired handling targets.

In today’s automobile industry refined NVH performance is a key feature and of high importance governing occupant comfort and overall quality impression of vehicle. In this paper interior noise and vibration measurement is done on one of the light truck and few dominant low frequency noise booms were observed in operation range. Modal analysis was done for the cabin at virtual as well as experimental level and few modes were found close to these noise booms. Vibrations were measured across the cabin mounts and it was found that the isolation of front mounts is not effective at lower frequencies. Taking this as an input, the mount design was modified to shift the natural frequency and hence improve the isolation behavior at the lowest dominant frequency. This was followed by static and dynamic measurement of the mounts at test rig level to characterize the dynamic performance and stiffness conclusion.