A composite material design tool

Layup Creation and Edits

The Material Manager provides interactive graphics for managing metals, foams, honeycomb cores, ply tapes and fabrics. You can build composite laminates with any arbitrary stacking of materials. Use native Windows cut, paste, and copy functions for quick ply insertions and layup arrangements.

Composite Interactive Analysis

Calculate [A,B,D] stiffness and thermal terms and equivalent orthotropic properties. Graph temperature dependencies, failure envelopes, and stress/strain profiles interactively. Choose from many popular composite failure theories such as Tsai-Wu. Perform highly interactive 'what-if' design changes and see their effects real time. A Windows database (Access®) forms the underlying software foundation for all HyperSizer products. The open structure of the material database schema allows software developers to use it for their own tool development. 

Composite Failure Criteria

Many different composite failure criteria are provided. These fall primarily into three categories. The first is the more traditional ply approaches such as max strain, max stress, and quadratic interaction (for example, Tsai-Wu). All of these failure theories use the same primary material moduli and strain/stress allowables.

The second category of failure criteria are physically based approaches that attempt to distinguish between fiber and matrix failures. Hashin’s failure criteria was one of the first theories in this category, but recently NASA Langley has developed a theory in 2004 called LaRC03, that in many ways is as good as the Puck theory that was reported in the World Wide Failure exercises as being the most accurate. An end-user advantage to LaRC03 over Puck is that the additional material data required for its use is relatively easier to obtain, or if not available, can be approximated. For the most part the data required to execute the physically based failure criteria are essentially the same as traditional ply theories.

The third category of composite strength prediction are laminate approaches. A laminate approach does not attempt to define stress/strain allowables at the ply level, but instead for the laminate and has the advantage of being capable of more accurately capturing the effects of percent plies in the different layup orientations, but it has the disadvantage of requiring much more testing to establish allowables.  The allowables are essentially represented as design curves as function of %plies. The design curves can be for notched (damaged) and unnotched laminates.  Four different techniques are provided for characterizing these curves, such as the two-dimensional Angle Minus Load (AML) and more advanced three-dimensional polynomials. The laminate approach, by definition, requires a different set of material allowables. However, all the property data required for these different approaches, including temperature dependent data, is conveniently saved as one material, under one material name in the database. 

The graphic displays these different failure criteria. Along side each failure criteria is a numerical value representing the lowest margin-of-safety (MS), of any ply, to any loadcase, of the laminate. The red font indicates a negative margin (-MS), and for this example occurs for the Tsai-Wu ply based failure analysis, and also for the laminate based open hole tension allowable. The ‘(+) Load’ message in the MS cell indicates that the load is tensile and not applicable for the compression allowable check. Red also indicates a very low MS (for example with Hashin, likely because incorrect material data was entered for its additional data requirement).

Open hole tension (OHT) and compression (OHC) allowables can also be defined on the ply or laminate approach. For this example composite analysis, both ply and laminate based failure criteria were toggled on for OHT and OHC, but ply based material strain allowables for open holes were not entered into the material database. So the failure tab indicates that “Data is Required” in red font for these analyses. The user can choose to either enter in the required data, or turn off these failure criteria.  

Composite failure analyses have been validated to the World Wide Failure Exercises (WWFE) test data. This WWFE test data, along with hundreds of other test data, is used in an included probabilistic method reliability analysis based on correlation factors for test scatter and analysis inaccuracy

Advanced Composite Analysis Topics

• Composite Strength Reliability Analysis »
• Advanced Composite Strength Analysis »
• Laminate based strength approaches such as AML and polynomial test data curve fits »
• Open hole tension (OHT) and open hole compression after impact (OHC) allowables »
• Physically based fiber/matrix failure theory »
• Damage tolerance Strain Energy Release Rates (SERR) and the Virtual Crack Closure Technique (VCCT) »
• Composite bonded joints »
• Composite bolted joints »
• Micro-mechanics »