Ciro A. Soto

A design model to predict optimal two-material composite structures

A method is presented for the prediction of optimal configurations for two-material composite continuum structures. In the model for this method, both local properties and topology for the stiffer of the two materials are to be predicted. The properties of the second, less stiff material are specified and remain fixed. At the start of the procedure for computational solution, material composition of the structure is represented as a pure mixture of the two materials. This design becomes modified in subsequent steps into a form comprised of a skeleton of concentrated stiffer material, together with a nonoverlapping distribution of the second material to fill the original domain. Computational solutions are presented for two example design problems. A comparison among solutions for different ratios of stiffness between the two materials gives an indication of how the distribution of concentrated stiffer material varies with this factor. An example is presented as well to show how the method can be used to predict an efficient layout for rib-reinforcement of a stamped sheet metal panel.

Structural Topology Design Optimization for Controlled Crash Behavior

This paper presents a methodology to perform structural topology design optimization for crashworthiness considering a prescribed and safe structural behavior through the dynamic equilibrium equation. This implementation, called here controlled crash behavior, or CCB, is very useful for design engineers in the automotive industry since it allows them to ‘prescribe’ a structural behavior of the vehicle at given locations of interest. The methodology is based on previous work from the author where the optimum topology is determined using a heuristic (optimality) criterion to attain a design with prescribed levels of plastic strains and stresses. The paper includes a simple beam example to demonstrate the CCB approach. Results are consistent with the formulation of the optimization problem.Copyright

Integration of Traffic Simulation and Propulsion Modeling to Estimate Energy Consumption for Battery Electric Vehicles

The introduction of battery electric vehicles (BEV) creates many new challenges. Among them is driving a vehicle with limited driving range, long charging time and sparse deployment of charging stations. This combination may cause range anxiety for prospective owners as well as serious practical problems with using the products. Tools are needed to help BEV owners plan routes that avoid both range anxiety and practical problems involved with being stranded by a discharged battery. Most of these tools are enabled by algorithms that provide accurate energy consumption estimates under real-world driving conditions. The tools, and therefore the algorithms must be available at vehicle launch even though there is insufficient time and vehicles to collect good statistics. This paper describes an approach to derive such models based on the integration of traffic simulation and vehicle propulsion modeling.

Structural Topology Optimization Under Impact Loads Using Beam Ground Structures

This work presents a methodology to find the optimal topology of a three-dimensional structure subject to impact loads, using the approach of ground structure. The method uses of the concept of topology optimization as a material allocation problem, which has been successfully used in the past to design structures modeled with shell and solid finite elements in the automotive industry. A simple example is shown to demonstrate the method.Copyright

A METHOD FOR THE OPTIMAL DESIGN OF COMPOSITE CONTINUUM STRUCTURES

Introduction The model presented here comprises an application of the approach to formulation of optimal design problems where the modulus tensor of the elastic structural continuum material appears in the role of design variable [ see e.g. Bends<j)e et al (1994) ]. A procedure used in conjunction with this model to generate results for optimal layout (topology), namely the weighted unit relative cost method described in Guedes & Taylor (1997), is exploited for present purposes to predict the configuration of reinforcing material in composite structures. The procedure leads from a design at the start having continuously varying material properties through a stepwise procedure to the result providing the layout in the composite of concentrated reinforcement. The stepwise procedure is described in the form of an algorithm. Experience with its implementation for computational treatment indicates that the method is dependable and robust. Results for application of the method to the design of a cylindrical structure with relatively low volume ratio (sparse), and to the prediction of an optimal composite beam are described.