Several computer-aided tools have been introduced for engineers in order to satisfy different requirements
not only to design (i.e. CAD) but also to the broader areas of manufacturing (CAM) and enterprise-wide issues
(CAE) [10, 13]. Based on this philosophy, we provide an efficient computer-aided tool, called CAROD (Computer-Aided Reliable and Optimal Design), which integrates the reliability and the cost requirements into the design process. Not only a large amount of mathematical and numerical techniques are available in CAROD system but also the use of the concurrent engineering concept allows us to reduce the design phase and to satisfy cost and safety requirements. There are many perceptions about the nature of concurrent engineering. For example, [7] defined concurrent engineering as being “the process of forming and supporting multifunctional teams that set product and process parameters early in the design phase”. Therefore, concurrent engineering is designing for cost, safety, performance, manufacturability, assembly, availability, … etc. Therefore, CAROD system integrates several fields such as multidisciplinary optimization, reliability analysis, finite element analysis, geometrical modeling, sensitivity analysis and concurrent engineering.

When integrating these disciplines, many difficulties can be found such as model coupling and computational
time. Multidisciplinary optimization is a way of finding the “best” solution, given an objective and a set of
constraints, where the objective, the constraints and the variables come from the knowledge built in different
disciplines. In the last decade, multi-objective optimization has gradually crept in engineering [17]. Topology optimization, shape optimization, sizing optimization and reliability-based design optimization are components
of multidisciplinary optimization. The Reliability-Based Design Optimization(RBDO) is a multi-objective optimi-
zation because it extends optimization theory by allowing multiple objectives to be “optimized” simultaneously.
The principle of this concept is to integrate the reliability analysis in the design optimization problem in order to minimize the cost and to maximize the reliability level. Since the introduction of reliability considerations in
the shape optimization problems allows us to meet cost and safety requirements, we propose herein to integrate the reliability analysis in the topology optimization problem. This integration leads to a really optimal
topology and design. In the following sections, we present the CAROD system and then we explain how each
component is integrated in the process, a special attention is given to the RBDO components. Finally, two en-
gineering applications are illustrated in order to show the performance of the proposed methodology.