No abstract

No abstract

<div class="section abstract"><div class="htmlview paragraph">Two wheelers are very popular as means of transportation in ASIA. Chassis is a very critical part of a two wheeler taking most of the loads coming from the roads. During the design and development stage, stiffness of the frame needs to be established. Stiffness is one of the critical parameter, which decides the handling performance of the vehicle. Conventionally, the main tube of motorcycle frame will be of uniform cross section throughout the axis of the tube. Variable thickness cannot be achieved in this method. In the new process called hydro forming, variable sections can be achieved. FE analysis has been done on the frame and the stresses are predicted. The stress pattern helped in identifying the critical areas. The critical areas identified are validated through experimental strain measurement. The validated model is further used to optimize the design by reducing the stresses at critical areas to below the acceptable limit &amp; improving the stiffness values. The final optimized frame cleared the structural &amp; handling tests without any failure. With this method, we were able to improve the stiffness to weight ratio.</div></div>

No abstract

<div class="section abstract"><div class="htmlview paragraph">In recent times gearless scooters are becoming popular means of transport in ASIA because of their ease of handling in crowded traffic and superior comfort over motorcycles. Major difference, which is contributing for least vibrations incase of scooters is mechanism of engine mounting on the frame. In most of the cases motorcycle engines are rigidly fixed to the frame where as in case of scooters engine will be swinging with respect to frame. It is easy to design muffler mounting for fixed engines. Since there is no relative motion between engine and frame for motorcycle both can be fixed to frame. Swinging scooter engine demands muffler mounting directly on engine. These direct mounts may include bosses, brackets, and bolts. While useful for their intended purpose, it is possible that vibrational energy can pass between the exhaust components and the engine through this direct mounting. This occurs due to directly coupling a large radiating surface (the exhaust component) to an active vibrating structure engine. There is also the possibility that the exhaust mounting bolts get loose because of vibration and in turn leads to shear failure of bolts and structural failure of muffler and engine parts.</div><div class="htmlview paragraph">This paper is aimed at simulating complex behavior of muffler mounting system for scooter engines in design level itself. Critical locations for structural failure are identified through first level simulation and these critical areas are used for measuring the strain experimentally. Simulation model for the existing design was refined through experimental measurement of natural frequencies and strain values. On validated simulation model Design of Experiments (DOE) was done for minimizing stress at critical locations and optimize design. The concept of robust design was used for optimizing the design for manufacturing and assembly variations. Optimized design through this process helped us in reducing product development cycle by minimizing number of physical prototype testing.</div></div>