Patent ID: 8433549

Claim:
A finite element method for simulating a structure employing multi-directional composite fibers, said method comprising: providing input data concerning the composite fibers; identifying a plurality of elements in the structure where each identified element of the plurality of elements includes a plurality of fibers having different orientations; for each of the identified plurality of elements, calculating a stiffness of each fiber in each of the identified elements, using the calculated stiffness of each fiber to calculate a stiffness of packets of fiber orientations, using the stiffness of the packets of fiber orientations to calculate engineering constants of the element that identify the stress of each of the identified elements for the combined fibers in each of the identified elements and calculating equivalent stress limits for a layer set-up of each of the identified elements; using the calculated engineering constants to calculate the stress on each of the identified elements; determining whether the calculated stress on each element of the identified elements exceeds a first predetermined stress limit; determining that the structure is satisfactory if the calculated stress on each element of the identified elements does not exceed the first predetermined stress limit; performing a ply-wise calculation of stress for each fiber in a particular element of the plurality of identified elements if the calculated stress for the particular element exceeds the first predetermined stress limit; and determining that the particular element is satisfactory if the ply-wise calculation of stress for each fiber in the particular element does not exceed a second predetermined stress limit.