Material Modeling and Structural Analysis


Swami Venkat, M.Sc.

Contact Person

Tel. +49 (89) 289 - 10385
E-Mail
venkat@lcc.mw.tum.de

The Material Modeling and Structural Analysis research team focuses on the structural analysis of fiber reinforced plastics as well as mechanical and bonded joints at different length scales.

One research focus is the prediction of the constitutive behavior of textile-reinforced composites using unit cells. We develop new methods for measurement and prediction of non-linearities, such as plasticity and damage in composites and bonded joints. This requires development, application and validation of novel constitutive laws. Additionally, experiments are conducted to gain a better understanding of the material behavior, generate input values and validate the models. The structural analysis focuses on the application of these models on macroscopic problems, such as the analysis of structural joints and major components, including wind turbine blades, aircraft and automotive structures.

Textile / Braided Composites

Utilizing textile processes such as braiding in the production of carbon fiber reinforced plastics (CFRP) allows a significant decrease in manufacturing cost and cycle time. Due to their textile architecture, braided composites exhibit a reduction in stiffness and strength compared to traditional unidirectional composites. Research at the LCC includes experimental material characterization as well as unit cell and analytical material modeling in order to develop new structural analysis methods for braided composites.

Figure 1: Experimental characterization and unit cell modeling of braided composites

Damage and Failure Modeling of Composite Materials and Structures

Due to the distinctive heterogeneous and anisotropic behavior of CFRP materials the failure of composite structures is affected by several different local damage processes. Hence, it is reasonable to exceed the currently widely used assessment of the initial damage in order to consider the damage progression processes as well. Research is undertaken on material modeling, with the focus on stiffness and damage modeling and failure analysis on material and structural level.

Figure 2: Simulation of matrix damage progression during an OHT-test

Influence of Fiber Waviness on Stiffness and Strength Behavior

Fiber waviness is a frequently observed phenomenon during the manufacturing process of wind turbine blades. There are various causes for fiber waviness: it may e.g. occur during the draping and the curing process. The LCC researches the analytical, numerical and experimental evaluation of these manufacturing effects regarding stiffness and failure behavior.

Figure 3: FE analysis of a wind turbine blade

Analysis and Simulation of Adhesively-Bonded Joints with Fiber-Reinforced Adherends

Adhesive bonding is an increasingly utilized joining technique for modern engineering structures. Joints with fiber-reinforced adherends, in particular, can benefit from the advantages of adhesive bonding, as loads can be introduced into the structure via large surfaces and fibers do not need to be cut in the joining process. However, analysis of adhesively-bonded joints with fiber reinforced adherends presents some challenges. At the LCC research is focused to make scientific analysis techniques applicable for engineers to design safe and lightweight joints. Another focus of research lies in the numerical simulation of bonded joints under rate dependent loading, such as in crash applications.

Figure 4: Simulation and experiment of a single-lap joint

Interference-fit Assemblies

Introducing loads into composite components is often a critical point in the design and analysis process of such structures. At the LCC a variety of different shaft-hub-connections for torsionally loaded structures is investigated. The focus is on interference-fit assemblies that are suitable for composite parts due to their 2-dimensional load introduction. With numerical calculations shaft-hub-connections are investigated in terms of non-axis-symmetrical loads and viscoelastic material behavior.