Steering Wheel Core 진동해석을 통한 최적화 설계에 대한 고찰

With rapid change of automotive market, multi-function and complexity in limited shape, cost reduction and weight lightening become more and more popular topic in these days. So it is necessary to study on design optimization. Steering Wheel is one of the parts that drivers touch very often in a car and its main function is steering. Especially, steering wheel vibration and noise becomes one of important quality evaluation criterion. Steering Wheel needs to meet basic strength, resonance by low natural frequency, natural frequency that meets more than optimum level and avoids fatigue fracture. Though steering wheel weight will be increased and natural frequency will be decreased relatively, designers often add rib shape on weak part for strength reinforcement and optimum natural frequency. So those methods do not work effectively. This study focus on the method that improves both of strength and natural frequency by change of geometric moment of inertia through changing cross section shape of spoke (2~4 spoke) and keeping mass at same time.Model of steering wheel core for study was simplified and every model’s rim and base keep its own shape and changed only cross section shape of spoke. Natural frequency of steering wheel core was checked by Nastran FX that used as study solver (Mesh size: 2㎜, node qty: 390,000 ~ 430,000EA, element qty 240,000 ~ 250,000). The study was conducted at same condition of armature mass by every spoke quantity. It is possible to confirm the correlation between cross section size change and its natural frequency of steering wheel core through natural frequency study and it is also possible to apply cross section size change on stress concentrated point occurred for strength reinforcement. As result, it can be judged that cross section change in same mass works on strength reinforcement, high natural frequency and cost reduction.