Increasing the Bearing Capacity of Composite Plates in the Zone of Bolted Joints by Using Curvilinear Trajectories and a Variable Fiber Volume Fraction

Curved continuous fiber trajectories for composite plates with a bolted joint corresponding to the lines of maximum principal stresses were designed using the iterative finite-element modeling. On their basis, variable stiffness composite structures were modeled by the finite-element method, when each element was assigned variable material properties depending on the distribution of fiber trajectories. To simulate the progressive failure of the plates, a material property degradation method was employed. An analysis of progressive failure showed that it is possible to significantly increase the ultimate load and reliability of bolted joints of composite structural elements by transition from the unidirectional to a curvilinear reinforcement.