Recurring cost minimization of composite laminated structures-optimum part size as a function of learning curve effects and assembly

The cost of a laminated composite plate is examined in detail. The fabrication process is broken out into individual steps and simple equations to estimate the cost on the basis of part size and complexity are developed. The option to divide the plate into modules is also included in the approach. The effects of learning curve and assembly are also incorporated. The cost equations developed are implemented in a simple optimization algorithm that minimizes the fabrication cost as a function of module size, overall plate size, thickness, learning curve, and fastener type and spacing. It is found that there is a range of values for these parameters for which the total cost of the plate is lower if it is made by assembling smaller identical modules instead of making it in a single piece. There is a module size that minimizes the total fabrication and assembly cost and results in cost values significantly lower than the cost of the plate if it were fabricated in one piece. The modular approach is also compared to an approach where the plate is made of pieces optimized locally for minimum weight based on local applied loads. The cost of the plate made by identical modules (at the optimum size found by the analysis) is found to be lower than that for a plate assembled with pieces each of which is optimized for weight. On the other hand, the weight of the plate made by identical modules is higher than the weight of the plate made by assembling pieces locally optimized for weight.