An increase in the use of composite materials in areas of engineering has led to a greater demand for engineers versed in the design of structures made from such materials. This book offers students and engineers tools for designing practical composite structures. Among the topics of interest to the designer are stress-strain relationships for a wide range of anisotropic materials; bending, buckling, and vibration of plates; bending, torsion, buckling, and vibration of solid as well as thin walled beams; shells; hygrothermal stresses and strains; finite element formulation; and failure criteria. More than 300 illustrations, 50 fully worked problems, and material properties data sets are included. Some knowledge of composites, differential equations, and matrix algebra is helpful but not necessary, as the book is self-contained. Graduate students, researchers, and practitioners will value it for both theory and application.

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A beam theory for open and closed section, thin-walled, composite beams is presented. The layup of each wall segment is arbitrary, the effects of shear deformation and restrained warping are neglected. Closed form expressions are developed for the calculation of the 4×4 stiffness matrix. It is also shown that the local bending stiffnesses of the wall segments may be neglected when the laminate is either symmetrical or orthotropic.

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The changes in shapes of fiber-reinforced composite beams, plates and shells affected by embedded piezoelectric actuators were investigated. An analytical method was developed which can be used to calculate the changes in shapes for specified applied voltages to the actuators. The method is formulated on the basis of mathematical models using two-dimensional, linear, shallow shell theory including transverse shear effects which are important in the case of sandwich construction. Solutions to the governing equations were obtained via the Ritz method. A computationally efficient computer code with a user-friendly interface was written which is suitable for performing the numerical calculations. The code, designated as SHAPE1, provides the change in shape for specified applied voltages. To validate the method and the computer code, results generated by the code were compared to existing analytical and experimental results and to test data obtained during the course of the present investigation. The predictions provided by the SHAPE1 code were in excellent agreement with the results of the other analyses and data.

In this article, a new model for FRP-confined circular concrete columns based on a sophisticated material model is presented. With the aid of this model the effect of the stiffness of the confining material on the strength of the structure was investigated. It was found that: (i) in the case of a wide parameter range (low-stiffness confinement) the stiffness has a minor effect on the concrete strength; (ii) in the case of high-stiffness confinement a significant gain in concrete strength can be reached by taking into account the confinement stiffness; and (iii) in theory the concrete can be overconfined (with a lower strength); however, this case is not realistic for conventional FRP. Based on the new model an analytical expression is derived to determine the (lower limit of) strength of confined concrete, and the limit of insufficient confinement is also derived. The results are verified by experiments available in the literature.

The changes in shapes of fiber-reinforced composite beams, plates and shells affected by embedded piezoelectric actuators were investigated. An analytical method was developed to determine the voltages needed to achieve a specified desired shape. The method is formulated on the basis of mathematical models using two-dimensional, linear, shallow shell theory including transverse shear effects which are important in the case of sandwich construction. The solution technique is a minimization of an error function which is a measure of the difference between the deformed shape caused by the application of voltages and the desired shape. A computationally efficient, user-friendly computer code was written which is suitable for performing the numerical calculations. The code, designated as SHAPE2, gives the voltages needed to achieve specified changes in shape. To validate the method and the computer code, results generated by the code were compared to existing analytical and experimental results. The predictions provided by the SHAPE2 code were in excellent agreement with the results of the other analyses and data.