Session: 01-04-02: Advances in Aerospace Structures

Paper Number: 137443

137443 - Agile and Resilient Parametric Stiffened Structure Concepts Leveraging Seamless Modeling and Simulation (Modsim) in 3dexperience Platform 

Many industrial structures rely on stiffening elements to provide lightweight panel designs thanks to their high strength-to-mass and stiffness-to-mass ratios. Combined with composite materials, it provides a very wide design space enabling to look for even lighter structures. Indeed, the layouts, cross-sections and material properties of the stiffening elements as well as the panel’s skin and material properties (metallic or composite) can be tailored to achieve the design requirements. However, this also represents a significant design challenge, as a compromise between the skin definition (resulting from the external shape) and the stiffening structure (which can be managed with significantly different stiffener arrangements) must be found. In addition, handling the connection between the skin and the stiffening elements is not trivial as it significantly impacts the design depending on the method used (fastening, bonding, soldering, …) and must thus be taken into account as early as possible in the design process. Finding the best design alternatives is achieved by ranking their simulation KPIs (stiffness, strength, stability, dynamic, …) which require the computation of simulations models. The related challenge is to chose the simulation model’s refinement to find a compromise between the cost and accuracy of the computation. 

The objective of this work is to straightforwardly build variable refinement simulation model by leveraging the 3DEXPERIENCE Platform, which enables to always keep the design and simulation content synced (MODSIM). The method relies on new technologies that can be found in these two roles: Concept Structure Engineering and Stiffened Structure Concept. The former enables to build a robust definition of the shape for a conceptual exploration. The Stiffened Structure Concept role is used to parametrize the material definition (multi-materials and variable thickness definition) thanks to a partitioning of the design surfaces, called the Grid. This partition enables to define different laminates over each cell. A further advantage of the role is that when composites laminates are defined, thanks to the Grid, composite plies for detailed design and manufacturing preparation can be automatically generated. Both roles combined thus allow both the control of robust shapes and material definition to generate different Finite Elements Representations (FEM). Three different levels of representation can then be defined: smeared, hybrid beam-shell and explicit shells. The most simplistic representation is the smeared approach in which the stiffness of the stiffeners is merged to the stiffness of the skin which is modeled by shell elements. This allows the global sizing but limits the understanding of stress analyses. To retrieve the internal forces in the stiffeners, a hybrid beam-shell representation is used, where the stiffeners are modeled by beam elements attached to the skin modeled by shell elements. Latest configuration is to fully model both skin and stiffeners using shell elements with the fastener definition (bolted, glued, …). The stiffeners are properly offset-ed considering the thickness of the skin having varying material definition. 

The proposal for the study is to apply the robust conceptual engineering capabilities to the design of a wind turbine blade. The objective is to manually trade-off on the shape, material definition and loads and measure their effects on the simulations KPIs. Relying on a hybrid FEM model, most of the blade is modeled with 1D beam elements. The root and trailing edges at the largest position of the blade profile are modeled with 2D shell elements to measure the local wall buckling modes with maximum computation accuracy.

Presenting Author: Pierre-Yves Mechin Dassault Systèmes

Presenting Author Biography: Alongside graduation with a PhD in Material Sciences & Engineering Mechanics, Pierre-Yves Mechin worked for the Marine engineering of racing yachts (60 feet boats IMOCA, VOR 70 feet, Ultime boat, America’s Cup...) to contribute on structural design and material mechanical tests. In 2017, he joined Dassault-Systèmes as part of the CATIA Composites team to pursue the double goal of first improving the accuracy of virtual simulation, taking into account the microstructure of composite & possible effect of defects, second of extending the unique 3DEXPERIENCE to deal with integrated Design, Simulation & Manufacturing.