The present article gives a new direction for quality modeling and analysis of polymer matrix composite products. Quality of composite products depends upon conformance of requirements of the customer. These requirements are translated into design specifications of all the contributing factors and subsystems up to component level of composite system. Quality of interaction amongst different subsystems, sub-subsystems, and other factors affects quality of products are also to be considered. Therefore, the present article considers quality of subsystems as well as quality of all interactions together and modeled using graph theory, matrix algebra as quality graph, quality matrix, and quality permanent function of the composite product. These models are useful to design quality of every subsystem and factors in such a manner that can lead to achieve sixsigma limits (almost zero error) i.e. 3.34 defects per million products produced. A number of analytical tests derived from these models help to carry out optimum selection of qualities of subsystems and interactions for designing competitive composite products. SWOT (strength-weakness-opportunities-threats) analysis integrated with these models becomes very powerful tool to convert an unsuccessful product into successful competitive product. Evaluation, ranking, and comparison procedures can be developed with the help of these proposed models. Coefficients of similarity and dissimilarity are developed for comparison among feasible products.Step-by-Step procedure based on systems approach is useful to designer, manufacturer at conceptual stage of design, and during manufacturing stages of composite products. This is basically a virtual prototyping methodology of complete system, leading to high quality competitive composite products. POLYM. COM-POS., 27:329 -340, 2006.

An attempt is made to develop an integrated systems model for the structure of the composite product system in terms of its constituents and interactions between the constituents and the molding processes, curing kinetics, etc. using graph theory and matrix algebra. The composite product system is first modeled with the help of a graph theory, then by a variable adjacency matrix and then by a multinomial known as a permanent function. The permanent function provides an opportunity to carry out structural analysis of the composite product in terms of strength, weakness, improvement, and optimization by correlating the properties of a composite with its structure. A physical meaning has been associated with each term of the permanent function. Different structural attributes of the composite product are identified to develop a graph theoretic model, a matrix model, and a multinomial permanent model of the composite. A top-down approach for complete analysis of any composite product system is also given. A general methodology is also presented for characterization and comparison of two composite product systems. Usefulness of the present methodology is also illustrated.

The paper describes a methodology for evaluation, coding, ranking, and optimum selection of subsystems for composite product used directly by its manufacturers. This method is important from the point view of development of a reliable database, virtual design, customization, developing cutting-edge technology, and meeting the challenges of global competition in composite industry. The 77-attribute electronic coding scheme and the evaluation techniques presented in this paper are useful to the designer during all the phases of design process, and manufacturer for the selection of optimum subsystems, which meet global market requirements. Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) is a Multiple-Attribute Decision Making (MADM) approach, used for selection of subsystems for a composite product development in order of preference for given application. Two graphical methods of MADM approach for evaluation and comparison are also introduced. The proposed 3-stage selection methodology is explained with an illustrative example.

In this paper, a numerical method for the free vibration analysis of cantilever quadrilateral plates of general shape is presented. Using quadrilateral coordinates and integral equation of beams, the expressions for the strain energy and kinetic energy have been developed. The formulation and derivation of equations are in the matrix form "ab initio." Then the eigenvalue problem is solved for frequencies and mode shapes. Numerical work has been done for particular cases and the results compared with those of other investigators. The effect of sweep back angle has also been studied.

The resin transfer molding (RTM) process has been widely accepted for fabricating automobile, aircraft, and spacecraft components with high strength and stiffness to weight ratios of the composite products. This process is widely acceptable in various industries, i.e., wherever low manufacturing cost with high mass production is required compared to other processes like compression molding and hand lay-up. Designing the composite products requires a lot of skill with multidisciplinary knowledge. Considering the design and the manufacturing strategies as well as the product development, every aspect of the design is to be considered in a single approach without losing any information. The present approach gives a new methodology for combining all the design aspects together in concurrent design methodology, which finally leads to the achievement of the six-sigma limits i.e., almost defect-free products from the RTM technology. The present paper utilizes the advantages of the graph theoretic approach to considering all the design aspects together in a single methodology with the help of matrix algebra and permanents. It is basically a virtual design methodology, which decides the process, the product strength, and the weakness with the help of a multinomial defined by using the matrix algebra. The design index, developed using the proposed methodology, really decides if the overall design is acceptable or not by considering all the aspects of the design related to the product, process, environment, etc. Finally, a step-by-step procedure is proposed to help generate a new algorithm for software coding.