Dynamic Analysis and Shape Optimization of Free Falling Steel Insert Used In Hand Brake Valve 2015-26-0205
The present investigation deals with the design and shape optimization of the steel insert used in the hand brake valve to withstand the impact load during brake off condition. This hand brake valve is used in the vehicles for parking brake application. It consists of a steel insert with a helical coil spring for locking and unlocking of a lever during brake on and off condition. Also a torsion spring with a cam mechanism is used for opening and closing of a hand brake valve. When the lever is locked the flexible elastic object (torsion spring) stores the mechanical energy when it is twisted. When it is unlocked (braking off) it exerts a force (actually torque) in the opposite direction, proportional to the angle it is twisted. During the braking off condition the steel insert gains the angular velocity from the stored mechanical energy of the torsion spring. There by the steel insert hits the top cover of the hand brake valve Subjected to the repetitive shock impulses where the force acts for a very short period of time. The angular velocity is calculated from the principle of work and energy and impacting force is calculated from the principle of impulse and momentum. To capture the real time stresses dynamic analysis is carried out. In this paper, steel insert which forms part of hand brake valve is subjected to the force for a very short period of time is analyzed with the 3D model using solid 186 elements. To compute the natural frequency of the system subjected to impact loading modal analysis was carried out using Block Lancoz method in ANSYS and the first two natural frequencies were computed. In order to find out the dynamic response of the steel insert modal superposition technique is used. The dynamic displacement of the steel insert shows the exponentially dying down behavior before it receives the next disturbance. The real time stress at the time of impact in the critical region shows the design adequacy of the steel insert. Fillet sensitivity analysis shows the shape optimization at the critical region. The theoretical results are in good agreement with the experiment and it is verified through endurance test.