Internal forces for statically indeterminate structures having different moduli in tension and compression

When a different tension-compression elastic modulus is introduced into the statically indeterminate structure, the flexural rigidity EI is no longer a constant, which is different from that of classic mechanics, but becomes the function of the internal force, the calculation of the internal force in the structure is a nonlinear problem. In light of this, the formula of internal force in statically indeterminate structures with different moduli has been deduced, the iterative program for calculating nonlinear internal force developed, and examples analyzed. Finally, we put forth reasonable suggestions for calculating this kind of structure and a new idea in optimizing the structures by using different modulus characters. A new and simple analytical-iterative method has been provided for calculating practical engineering problems by using different-modulus theory. This is different from the previous complete numerical solution, which characterizes complex calculation procedure, heavy calculation work, and slow convergence speed. Moreover, a new perspective has been provided for studying the mechanics characters of composite materials.