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A METHODOLOGY FOR FINITE ELEMENT MODELING ACCURATELY ACCOUNTING FOR CASE-HARDENED STEEL WITH CONTINUALLY VARIED HARDNESS READINGS
ISSN: 0148-7191, e-ISSN: 2688-3627
To be published on April 14, 2020 by SAE International in United States
Presented here is finite element modeling of steel plates within which mechanical properties varied dramatically from their outer surfaces towards inside cores. The necessity to develop such a methodology in finite element analysis arises from the fact that many plate-structured components serving in automobiles are often made from relatively low carbon steel whose high ductility are needed for metal-forming operations. In order to strengthen the loading capability, various forms of heat treatment can be applied to a formed component, such as carburizing, carbonitriding, or induction-hardening. As a result, that component can no longer be considered as being homogeneous in its mechanical properties. Developing a finite element model that will truly represent what can be characterized as laminates has a great significance in the community of computer-aid-engineering. The benefits of this methodology will be discussed by numerous case studies of a centrifugal pendulum that has gained its popularity in high-end passenger cars because of its superior vibration suppression. The pendulum will be subject to excessively and destructive load due to centrifugal force at extremely high angular velocity. In the presented study, it can be shown that as the angular velocity is increased, the inner core with much softer mechanical properties quickly gets into the plastic state and significantly restrains it from carrying more loads. The outer case layers have to take an increased share of loads, and their stresses are rapidly raised. The author will study the effect of the thickness of hardened layer and hardness readings on the loading capacity. It is very interesting to demonstrate that it is the outer surface that would start to crack first, even if it has much higher ultimate tensile strength throughout the body, provided the load is destructive and non-cyclic. The attempt has been made to predict the maximum load capacity based on an intermediate result well prior to reaching its ultimate limits and compare it with the simulated results obtained exactly at the load of fracture.