Search Results

Many methods have been developed to evaluate the fatigue life of structures when the joints are as per ideal case. But if the joints are loosening, it leads to increase in loading on the other members which causes failures. Most commonly in commercial vehicle segment welding joint & bolting joints are most popular ones. It is very easy to find out bolts strength & loosening effect in static conditions. But when vehicle is moving (i.e. dynamic condition), same method cannot be used. For this we have developed methodology to predict the bolts loosening in dynamic condition using vibration data. Similarly, loading may differ on the structural members if the welds are failing in dynamic conditions. To overcome this problem, in our organization we have a solution. Of course to simulate welding failures fatigue analysis is mandatory. We are using notch-stress approach for evaluating the welding strength of the joint.

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].

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.

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 Mounting system of component plays a major role in determining the structural durability, compatibility and synchronization of the systems with respect to each other. The major function of Engine mounts is to isolate the engine from the chassis and to align the power-train system of vehicle according to needs. Here we exclusively deal with the failure case of a Heavy duty commercial vehicle Engine Mounts and its optimization. We do formulate a theoretical calculation for the estimation of engine loads, Center of Gravity (C.G) and characteristics of existing engine mount followed by a failure root cause analysis based on design and transmissibility parameters. This is then correlated with data from Computed Aided Engineering and Matlab for analysis of the existing model which is compared to the experimental transmissibility from Road load data Acquisition (RLDA). This is to validate the conditions and propose optimizations to reduce critical failures.

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.