Vladimir Glukhikh, Saint Petersburg State University of Architecture and Civil Engineering
2018 Architecture and Engineering  
The article presents a solution to a problem on the establishment of mathematical relations between elastic constants of anisotropic fiber composites in principal anisotropy directions. A stress function in the form of a polynomial sum was used to solve the fourth-order differential equation in partial derivatives for an orthotropic body, thus allowing determining elastic constants of fiber composites with different directions of reinforcing fibers by means of mathematical calculations. It was
more » ... lculations. It was established that all anisotropic materials could be conditionally divided into two groups. One group includes composites in which elastic constants take an intermediate extreme value at 60° upon change of the reinforcing fibers position from 0 to 90°. The other group includes composites with two extreme values -at 0 and 90°. This new knowledge obtained for the first time shall be used to provide rationale for the method of composite strength assessment by means of calculations depending on the position of reinforcing fibers, which was previously possible only upon execution of experimental studies.
doi:10.23968/2500-0055-2018-3-4-13-23 fatcat:r3gdk5ceejbq3ezu7c4we76puy