The Boeing Company

Vladimir Balabanov

Mostafa Rassaian

Olaf Weckner

Yuan-Jye Wu

Hong Hue Tat

Richard Joel Thompson

Adriana Willempje Blom-Schieber

Michael Andrew Epton

Evin J Cramer

Abdelhai Maysara Saadi

Zachary Robert Meves

A method, a computing system and a computer program product are provided to efficiently define a guide that includes one or more defined sets of ordered ply orientations. In the context of a method, a plurality of stacking sequence rules are received. The method defines the guide including the one or more defined sets of ordered ply orientations in accordance with a constrained, linear integer optimization formulation. In this regard, the method defines the guide by dividing the guide into a plurality of blocks and determining a plurality of sublaminate stacks that satisfy the stacking sequence rules and that have a size limited by a size of the blocks. For each of the plurality of blocks, the method determines in accordance with the constrained, linear integer optimization formulation a sublaminate stack from among the plurality of sublaminate stacks that is compatible with a respective block.

Computing system and method for defining a guide having one or more defined sets of ordered ply orientations

A system comprises a model generation system and an analyzer. The model generation system is configured to modify a model of a laminated composite structure to meet a user defined objective and to meet at least one of user defined performance constraints or user defined manufacturing constraints by changing at least one ply characteristic of at least one ply of the model while maintaining ply boundary geometry constraints for each ply of the model. The ply boundary geometry constraints of the model generation system include a number of defined ply boundary geometries each described by a respective mathematical function. The analyzer is configured to return objective values or constraint function values for at least one ply of the model.

Controlling and adjusting ply shapes of laminated composite structures for performance and manufacturing considerations

Composite skin-stringer structures which reduce or eliminate the risk of delamination at the skin-stringer interface. This can be accomplished by arranging ply directions (i.e., the angles of the fiber paths of the ply) in a layup in a way such that for the dominant loading, the skin and stringer will each deform in a way that reduces relative opening (fracture Mode I) and/or sliding (fracture Mode II) and/or scissoring (fracture Mode III) at the skin-stringer interface. This is possible when coupling between specific deformations modes is purposefully activated instead of being suppressed. The ply directions in the stringer are adjusted so that the stringer deforms in a controlled fashion to suppress or 'close' cracks that are about to form&#x2014;before the undesirable modes of failure form&#x2014;as load is applied.

Skin-stringer design for composite wings

A design process that uses lamination parameter inversion to generate a set of baseline layups having desired stiffness properties. Then the underdetermined Newton's method can be applied to explore solution manifolds describing alternative designs having similar if not identical stiffness properties. The manifold of solutions can be methodically examined to find those with desirable properties. Desirable properties include those that have been traditionally captured by design rules or those that improve manufacturability. Combining lamination parameters as design variables with lamination parameter inversion provides an efficient optimization process for non-traditional laminates.

Lamination parameter-based method for optimal design and manufacturing options

A method of generating an optimized design model for a composite laminate may include computing a normalized set of lamination parameters and laminate stiffness matrices of an initial laminate design, and determining, using an optimizer operating on a finite element model, optimum values for the lamination parameters and the laminate thickness. The method may further include adjusting the optimum value of the laminate thickness, and performing an inversion process extracting multiple solutions from the lamination parameters, each solution including a unique set of individual fiber angles for each ply and representing an optimized design model of the composite laminate.

System and method for designing composite laminates using lamination parameters

A method of configuring a composite laminate may include selecting at least two different material systems for the laminate. Each one of the material systems may have material properties and corresponding material invariants. The laminate may be comprised of a stack of plies having a stacking sequence. The method may include characterizing the stacking sequence using lamination parameters for each material system. The method may further include calculating a transverse shear stiffness of the laminate using the material invariants and the lamination parameters.

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Mukilteo, WA, United States of America

Vladimir Balabanov