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In engineering development, simulation methods are frequently used to perform thermal and mechanical stress components analysis. In brake systems, where the components are exposed to mechanical and thermal loads, the numerical analysis is very helpful. Once a numerical model for brake assembly is available, it will be possible to understand the effects of successive brake applications on the temperature distribution in drum brake’s friction materials. This is a fundamental aspect to determine, for instance, the thermal stress distribution which is related to the warming and cooling of the brakes. In this work, an analytical solution to calculate stabilized temperature was used to establish a heat flux through a pneumatic S cam drum brake’s friction material applied to a numerical model in a finite element analysis.

Brake drums are components designed to dissipate kinetic energy of vehicles, converting it, mostly, into thermal energy. The stress state originated by thermal transients produced by braking cycles may nucleate fatigue cracks and lead the component to failure. The aim of this work is to analyze and compare thermal fatigue strength for brake drums, made in vermicular cast iron, with different design geometry. Firstly, fatigue life has been evaluated for the original geometry. The same analysis has been performed after reducing the thickness of the brake drum. From thermal and structural analisys, via finite element method, temperature evolution and loading history for the component have been obtained. The life of the component has been estimated for the region with the highest probability for crack nucleation by thermal fatigue. The rain-flow method of counting cycles has been applied and Goodman equation has been used to evaluate the fatigue life of the component.

The AISI 41B30H steel is one of the materials used to produce cylinders for storing natural gas for vehicles. These pressure vessels are normally produced by flow forming of a seamless tube of this material and followed by spinning process, a hot forming process that closes the ends of the tube. In this work, the mechanical properties of an AISI 41B30H steel heat-treated in the intercritical region, to produces a dual-phase microstructure of ferrite-martensite have been studied and compared with that of the material in the normalized as-received condition. The determination of quenching temperature within the intercritical region was obtained using computer simulation with THERMO CALC software and these results have been validated by metallographic analysis. The forming properties have been analyzed by means of tensile tests.

The brake drums are designed to convert kinetic energy of the vehicle into thermal energy. The stress originated by thermal transients produced by braking process may nucleate fatigue cracks and lead the component to failure. The aim of this work is to study thermal fatigue life for brake drum made with gray cast iron and vermicular cast iron. The loading transients due to different braking events were determined by thermal analysis, using FEM methods. Stress amplitudes and mean stresses were obtained. The fatigue life of the component has been evaluated and the points with the highest probability for crack nucleation were determined. The highest level of stress was observed in the hoop direction when the brake drum is made in gray cast iron and in the radial direction when it is made with vermicular graphite cast iron.