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The functional performance of the mechanism plays a vital role in attracting customer concentration towards the product. It is the first interface for interaction with the customer. Hence it is important to evaluate the functional performance at the time of the design phase itself in order to eliminate the possibility of an increase in proto-builds. The functional performance of a mechanism comprises parameters like, a mechanism should perform its function for which it is designed, with minimum effort required and ease in functionality. Evaluation of such parameters at the design stage involves many assumptions and this brings chance variables in the methodology. In order to eliminate these assumptions, a methodology has been developed using the multi-body dynamics (MBD) model of mechanisms like gear shifting mechanism and cabin door outer handle mechanism.

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].

Leaf spring is a vital suspension component, such that the failure of leaf spring could cause fatal accidents. Due to frequent failures of leaf springs on vehicles, a method is developed to perform the numerical analysis using explicit solver which provides insightful analysis of leaf springs to prevent the occurrence of failure during engineering design. Since fatigue life assessment of leaf springs is a significant aspect during the design stage and due to the limitation of non-compatibility of output file of explicit solver for fatigue analysis, various studies are conducted and implicit solver is considered to perform FEA simulation of leaf spring. The present study delineates comparison of non-linear analysis of semi-elliptical leaf spring using explicit solver with that of implicit solver. Analysis using implicit solver gives us an advantage to export the model in fatigue life estimation solver which is not possible using explicit solver.

In an automobile, main function of the steering system is to allow the driver to guide the vehicle on a desired course. Steering system consists of various components & linkages. Using these linkages, the torque from steering wheel is transferred to tyre which results in turning of the vehicle. Over the life of vehicle, these steering components are subjected to various loading conditions. As steering components are safety critical parts in the vehicle, therefore they should not fail while running because it will cause vehicle breakdown. In commercial vehicle segment, vehicle breakdown means delay in freight delivery which results in huge loss to costumer. Therefore, while designing steering components one should consider all the possible loadings condition those are possible. But, it can’t be done through theoretical calculation. Therefore, physical tests have to be carried out to validate design of steering system, which is very costly & time-consuming process.

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 ensuring the comfort of the driver & passengers. The suspension also protects the vehicle itself and any cargo or luggage from damage and wear. Almost all heavy duty vehicles use inverted type suspension system which is also called as bogie type suspension system. The design of this type of suspension is a complex and difficult science which has evolved over many years. It was recognized very early in the development of suspensions that the interface between vehicle body and wheel needed some sort of cushioning system to reduce the vibration felt as the vehicle moved along. This was already part of road coach design and took the form of leaf (laminated) steel springs mounted on the axles, upon which the vehicle body rested.

At the time of invention of road coaches, the vehicle consisted only of an axle with wheels and a body attached. Smooth roads were built for a better ride comfort however they were not consistent. The road coaches were too bumpy and uncomfortable for the passenger along with the driver who was not able to control the vehicle. That's why the engineers had to shift their attention to the suspension system for a better ride comfort and handling. The technology has advanced with time so as the suspension system. Rubber ended type leaf spring is one of the suspension system types available in the industry. The main function of a suspension in order of importance is as below: 1 Acts as a cushioning device ensuring the comfort of the driver and passengers; 2 Maximizes the contact between the tires and the road surface to provide steering stability with good handling; 3 Protects the vehicle itself and any cargo or luggage from damage and wear.

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.

In commercial vehicle, Leaf Spring design is an important milestone during product design and development. Leaf springs are the most popular designs having multiple leaves in contact with each other and show hysteresis behavior when loaded and unloaded. Commonly used methods for evaluation of leaf spring strength like endurance trials on field and Rig testing are time consuming and costly. On the other hand, virtual testing methods for strength and stiffness evaluation give useful information early in the design cycle and save considerable time and cost. They give flexibility to evaluate multiple design options and accommodate any design change early in development cycle. A study has been done in Volvo-Eicher to correlate Rig result with Finite Element Analysis (FEA) simulation result of Multi-stage Suspension Leaf Spring, entirely through Finite Element Analysis route.

In commercial vehicle, Leaf Spring design is an important milestone during product design and development. Leaf springs are the most popular designs having multiple leaves in contact with each other and show hysteresis behavior when loaded and unloaded. Commonly used methods for evaluation of leaf spring strength like endurance trials on field and Rig testing are time consuming and costly. On the other hand, virtual testing methods for strength and stiffness evaluation give useful information early in the design cycle and save considerable time and cost. They give flexibility to evaluate multiple design options and accommodate any design change early in development cycle. A study has been done in Volvo-Eicher to correlate Rig result with Finite Element Analysis (FEA) simulation result of Multi-stage Suspension Leaf Spring, entirely through Finite Element Analysis route.