Simulation of lightweight structures in mechanical engineering

Transcription

1 Simulation of lightweight structures in mechanical engineering S. Hannusch 1 R. Herzog 2 M. Hofmann 3 J. Ihlemann 1 L. Kroll 1 A. Meyer 2 F. Ospald 2 G. Rünger 3 R. Springer 2 M. Stockmann 1 L. Ulke-Winter 1 1 Faculty of Mechanical Engineering, Technische Universität Chemnitz 2 Faculty of Mathematics, Technische Universität Chemnitz 3 Faculty of Computer Science, Technische Universität Chemnitz NESUS Working Group Meeting April 11, 2017 Bayreuth, Germany

2 Outline 1. Introduction 2. Simulation of lightweight structures 3. Optimization of lightweight structures 4. Experiments and validation 5. Summary and outlook April 11, 2017 M. Hofmann Simulation of lightweight structures in mechanical engineering 1 / 15

3 Introduction Outline 1. Introduction 2. Simulation of lightweight structures 3. Optimization of lightweight structures 4. Experiments and validation 5. Summary and outlook April 11, 2017 M. Hofmann Simulation of lightweight structures in mechanical engineering 2 / 15

4 Introduction Integrated Research Domain F within MERGE Modeling, simulation, and optimization of multifunctional lightweight structures Combining the examination of design and manufacturing conditions High precision simulation and multi-criteria optimization leading to high computational demands Research focuses Short fiber-reinforced plastics (SFRP) manufactured by injection molding Advanced material laws and manufacture-related residual stresses Component and manufacturing process optimization Efficient computing and data management strategies April 11, 2017 M. Hofmann Simulation of lightweight structures in mechanical engineering 3 / 15

5 Simulation of lightweight structures Outline 1. Introduction 2. Simulation of lightweight structures 3. Optimization of lightweight structures 4. Experiments and validation 5. Summary and outlook April 11, 2017 M. Hofmann Simulation of lightweight structures in mechanical engineering 4 / 15

6 Simulation of lightweight structures CFD simulation of the injection molding process Injection of molten plastic with mixed in fillers (e. g., glass or carbon fibers) Fiber orientations determine the mechanical properties of the parts Manufacturing parameters (e. g., injection position) influence the fiber orientation CFD simulation application Computational fluid dynamics (CFD) application based on OpenFOAM Compressible two phase flow with heat transfer and fiber orientation calculations Input: structure geometry, material properties, and manufacturing parameters Output: fiber orientation and temperature field within the structure April 11, 2017 M. Hofmann Simulation of lightweight structures in mechanical engineering 5 / 15

7 Simulation of lightweight structures FE simulation of cooling and load cases Simulation proceeds in two steps: 1. Instationary cooling process to obtain residual stresses 2. Operating load cases to determine mechanical properties Material of SFRPs described by a second order fiber orientation tensor FEM simulation application In-house 3D finite element method (FEM) application Adaptive mesh refinement based on residual type error indicators Input: structure geometry, CFD output (e. g., fiber orientation), load case Output: structure properties (e. g., deflection) under load April 11, 2017 M. Hofmann Simulation of lightweight structures in mechanical engineering 6 / 15

8 Simulation of lightweight structures Efficient computing strategies CFD and FEM simulations are compute-intensive (parallel) applications Numerical optimization performs simulations with different parameters Various software components, e. g.: numerical simulations control scripts data storage, transformation, visualization user interaction Various hardware platforms Simulation Component and Data Coupling (SCDC) Service-oriented coupling of independent software components Transparent data exchange across different computing platforms Communication library to cope with software and hardware diversities April 11, 2017 M. Hofmann Simulation of lightweight structures in mechanical engineering 7 / 15

9 Optimization of lightweight structures Outline 1. Introduction 2. Simulation of lightweight structures 3. Optimization of lightweight structures 4. Experiments and validation 5. Summary and outlook April 11, 2017 M. Hofmann Simulation of lightweight structures in mechanical engineering 8 / 15

10 Optimization of lightweight structures Injection molding optimization Injection Molding Process Optimization Tool (IMPOT) Configuration of optimization problems and parameters Selection of algorithms, applications, and compute resources Execution of solution methods and presentation of results GUI application and client that accesses simulation services Demonstration example Plate of Polypropylene with glass fibers Find injection position with minimal deflection! Kriging-based optimization algorithm: Arbitrary number of candidate positions Interpolation-based surrogate model April 11, 2017 M. Hofmann Simulation of lightweight structures in mechanical engineering 9 / 15

11 Optimization of lightweight structures Optimization of multilayer composites Demonstration example Three-layer composite consisting of carbon fibers Find ply orientations that maximize the minimal reserve factor of the component! Objective function has a large number of local maxima and requires derivative-free optimization algorithms Results of Nelder-Mead method depend on the initial ply orientations Advanced problems (e. g., more layers, additional manufacturing constraints) require nature-analogous algorithms (e. g., Particle Swarm Opt. or Ant Colony Opt.) / / April 11, 2017 M. Hofmann Simulation of lightweight structures in mechanical engineering 10 / 15

12 Experiments and validation Outline 1. Introduction 2. Simulation of lightweight structures 3. Optimization of lightweight structures 4. Experiments and validation 5. Summary and outlook April 11, 2017 M. Hofmann Simulation of lightweight structures in mechanical engineering 11 / 15

13 Experiments and validation Measurements of residual stresses Manufacture-related residual stresses influence mechanical properties Change stress state with hole-drilling to measure residual stresses Strain gauge rosettes measure only on the surface Embedding of Fiber Bragg grating (FBG) sensors for measurements in several depths 1. plain 3. plain Experiments Three epoxy plates with FBG sensors embedded in epoxy glue layers Fixed pressure on two sides to achieve a known stress state 5 mm hole, 9 mm depth in 1 mm steps Strain [µm/m] plain epoxy plates SG A SG B SG C Drilling depth [mm] April 11, 2017 M. Hofmann Simulation of lightweight structures in mechanical engineering 12 / 15 FBG A FBG B FBG C

14 Summary and outlook Outline 1. Introduction 2. Simulation of lightweight structures 3. Optimization of lightweight structures 4. Experiments and validation 5. Summary and outlook April 11, 2017 M. Hofmann Simulation of lightweight structures in mechanical engineering 13 / 15

15 Summary and outlook Summary and outlook Overview of the simulation and optimization approaches for lightweight structures consisting of fiber-reinforced plastics Coupling of software components with a dedicated communication library CFD and FEM applications for SFRPs exploit HPC resources Improve simulations, e. g. with advanced material laws Optimization of multilayer composites based on an analytic approach Coupling with numerical FE models and solvers Experimental method for measuring of strains in several plains Develop mathematical models for stress analysis April 11, 2017 M. Hofmann Simulation of lightweight structures in mechanical engineering 14 / 15

16 Acknowledgment This work was performed within the Federal Cluster of Excellence EXC 1075 MERGE Technologies for Multifunctional Lightweight Structures and supported by the German Research Foundation (DFG). Financial support is gratefully acknowledged. April 11, 2017 M. Hofmann Simulation of lightweight structures in mechanical engineering 15 / 15