Structural Response of a Protective Brake System Shield Under Thermal Load

Protective sheet-metal components located in the engine compartment are exposed to significant temperature variations generated by the powertrain and adjacent heat sources. These thermal loads can affect stress distribution, deformation behavior, and the performance of bolted joints. This study investigates the thermo-mechanical response of a steel protective shield mounted on a valve block support using an M6 class 8.8 bolted connection. A three-dimensional finite element model was developed to evaluate the assembly under an initial bolt preload of 8 kN and three thermal cycles between −40°C and +120°C. The analysis focused on equivalent von Mises stresses, total deformation, contact pressure, and bolt clamp force evolution. The results indicate that thermal cycling causes periodic variations in preload and localized stress concentrations, particularly around the mounting hole and geometric discontinuities. The maximum bolt force remained below the ISO 898-1 proof load limit, confirming elastic behavior of the fastener. Furthermore, no significant preload relaxation was observed, demonstrating that the assembly maintains adequate clamping performance and structural integrity under the investigated thermal conditions.