Reduction in strength requirements of material of the subframe of truck with independent suspension by topological optimization of the design and power scheme

The paper describes application of the method of topology optimization on the basis of finite element modeling when design highly loaded parts of the chassis of the vehicle. The brief theoretical information on method of optimization based on the application of the concept of body with variable density is given and two popular formulations of the problem were considered: with objective function in type of minimum strain energy of deformation and with objective function in type of minimum mass. In first case, constraints on objective function are set in the form of a maximum usage percentage of the original volume of space design, and in the second case, restrictions on objective function are set in form of maximum allowable displacements and stresses in the elements of space design. An example of the synthesis of the power scheme of the front sub-frame independent suspension of the truck with a description of the estimated model is given. For the solution of optimization problems were selected five the most heavy-load modes of the frame. The figure is shown of the available layout space design for subframe. The result of solving the problem of topological optimization is subject to a geometrical interpretation in the form of separate parts and combining them into assembly units. The result is the design of the subframe, close to the truss type (without the elements, working in bending and shear). For the design was carried out verifying calculation of strength at the same five load modes. The analysis results show the strength of low operating voltage in parts of the subframe, due to the lack of significant stress concentrators and compliance of space topology of the sub-frame structure to solution of the problem of topological optimization. Low operating voltage allows to use as construction material of sub-frame the cheap steel with low strength properties. Thus, the use of topology optimization to create an optimal constructive-power circuits of highly loaded structures allows to reduce the demands on the material properties while improving the performance characteristics of the products - durability, stiffness and reduced mass.

topological optimization, weight reduction, subframe, independent suspension, finite element method