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A methodology is presented to do accelerated vibration durability test, on Electro Dynamic Shaker (EDS) by using Power Spectral Density (PSD) profile based on typical customer usage pattern. A generalized iterative procedure is developed to optimize input excitation PSD profile on EDS for simulating the exact customer usage conditions. The procedure minimizes the error between the target channels measured on road and the response channels measured on EDS. Also, response of accelerometers and strain gauges at multiple locations on the test component are arrived at based on a single input excitation using this procedure. The same is verified experimentally as well. Different parameters like strain, acceleration, etc. are simulated simultaneously. This methodology has enabled successful simulation of road conditions in lab, thereby arriving at a correlation between rig and road. The correlation obtained is based on the simulation of the same failure mode as that of the road on the rig.

Scooters are becoming increasingly popular in India. Competition in this segment has forced the product developers to put focus on development time reduction and quality improvement. Any physical failure of critical parts in the actual customer usage conditions can delay the product launch. The present study is about simulation of failure of crankcase during field trials. This involved creation of Finite Element model, evolution of proper loading and boundary conditions which capture the failure area, development of a static and an accelerated dynamic test in laboratory to reproduce the field failure, the optimization of the crankcase design through FEM to achieve acceptable stress values at critical areas and validation of these results through newly developed laboratory tests. Simultaneously, field trials, which initially produced this failure were conducted and no failures were observed. Thus, the current study has saved time of actual field trials (3∼4 weeks) after the redesign.

In two wheelers the front suspension system is mounted on chassis by two steering bearings which are lubricated ball type angular contact bearings with significant radial force components. These bearings are designed to withstand maximum vehicle loads for target durability. Maximum load carrying capacity depends on the number and size of the balls, bearing size and material. For target durability with designed load carrying capacity, the ball contact pressure, bearing preload plays a major role as compared to other design parameters. Geometry parameters and maximum load defines contact pressure for given bearing design. But in two wheelers due to nature of usage and road conditions, the peak loads are dynamic and geometry based design calculations may not yield the most optimal bearing design. In this work the bearing ball race profile design is optimized by using dynamic bearing contact profiles by using nonlinear Finite Element Analysis.

Two wheelers are very popular as means of transportation in ASIA. It is also used as load carrier in some places. Chassis frame is a very critical part of a two wheeler taking most of the loads coming from the roads. During the design and development stage, structural integrity of the frame needs to be established. Bump test is one of the critical life tests performed on the vehicle for evaluating the fatigue life of the frame. Normally, three to four iterations take place before frame passes this bump test. This is a time taking test process (1week per iteration) and does not guarantee the end result. In the new approach, the bump test simulation is made using ADAMS software. The ADAMS model is validated by using the axle accelerations measured in the physical bump test. Subsequently, the loads obtained from ADAMS model are used in FEM software and the stresses are predicted. The stress pattern helped in identifying the critical areas.

Brake system is one of the most important safety related sub systems for any automobile. This requires all auto majors to put more effort in design optimization of brake system and exhaustive evaluation for the same. On-road evaluation of brakes is time consuming process and has other shortfalls like unsafe riding conditions, less repeatability, limitation of brake input force, speed, less control in test conditions, requirement of special track etc. Normal lab testing for brake system has several drawbacks like imprecise inertia simulation, more testing time, uncontrolled test environment, partial system level evaluation, huge rotating mass which may lead to unsafe operating conditions, frequent maintenance, etc. This paper describes about the methodology adopted, efforts involved and results obtained by developing an accelerated evaluation system for brakes as a complete sub system in laboratory.

A methodology is presented to obtain loads coming on the handle bar of a motorcycle of one model and calculating generic loads from the same for all other motorcycle models. The handle bar of a motorcycle of model M1 was instrumented with strain gages and calibrated for vertical and horizontal loads. The instrumented handle bar was assembled on the vehicle and data was collected on the test rig in laboratory. The vertical and horizontal loads acting on the handle bar, on test rig was obtained based on the calibration performed. The loads thus obtained are for a particular motorcycle model M1 and is dependent on the wheel loads of that motorcycle. These loads were converted into generic load cases, which are applicable for all models of motorcycles. The generalized loads thus generated were used in predicting the fatigue life of handle bar of a different motorcycle model (M2) using FE analysis and MSC fatigue.

This paper aims at the estimation of dynamic wheel loads of a two-wheeler through mathematical modeling that will aid during the initial stages of product development. A half car model that represents a two-wheeler was used for this purpose. Road displacements were given as input to the model and the wheel loads estimated. Actual road data obtained from two-poster rig was used as input to the model thereby making it possible to calculate the wheel loads for different customer usage conditions on different roads. In this paper, a severe rough road was chosen for verification of the model with that of the rig as the rider dynamics on such roads are the most difficult to simulate even on the rigs. The estimated values from model were verified with those measured using a two-poster rig for the same road displacement. Attempt has been further made to establish a correlation between the ride comfort predictions from the model and the two-poster rig.