Research Projects

Fatigue

• Global-local thermomechanical analysis of fracture in polycrystalline silicon shells using a phase-field approach.

  The photovoltaic (PV) modules containing multiple polycrystalline silicon solar cells (PSSCs) are one of the most common and widely used devices for the production of solar energy. However, the energy production efficiency degrades during their lifespan, which can be primarily associated with the cracking in a polycrystalline silicon wafer (PSW). The aim of this joint research project (ISD - Leibniz Universität Hannover, IAM - TU Braunschweig) is to evaluate the overall stiffness degradation of polycrystalline silicon solar cells (PSSCs) due to microcracking. PSSCs are intricate component consisting of multiple materials and modeling becomes computationally expensive. Therefore, modeling reduction techniques such as numerical homogenization were employed for evaluating the effective material properties of PSSCs including cracks. The cracks are to be modeled using a phase-field approach. An improved Voronoi-tessellation scheme was used to generate polycrystalline patterns of the PSW and a mean-field homogenization scheme was employed to determine the homogenized response of PSSCs. The accuracy of the homogenization scheme was verified and the material response of the heterogeneous and homogeneous PSSCs was compared.

  Led by: Prof. Dr-Ing. habil. Raimund Rolfes

  Team: M.Sc. Muzzamil Tariq, Dr.-Ing. Sven Scheffler

  Year: 2018

  Funding: DFG, German Research Foundation

  Duration: 01.08.2018 - 31.07.2021
• New methods for failure and fatigue analysis of suction panels for laminar flow control

  Although the suction panel concept holds a high potential to increase the sustainability of future aircrafts, it comes with some structural mechanical challenges that need to be carefully examined. With the panel’s underlying backbone structure adopting the load-carrying function of the outer airfoil in the suction area (see Fig. 1), the stress flux in the airfoil is considerably disturbed, resulting in multiple, potentially critical stress concentrations. To ensure a sufficient robustness of the suction panel concept in terms of static strength and fatigue resistance, the backbone structure is to be analyzed numerically by means of finite element simulations. With deep knowledge in the field of continuum damage mechanics and progressive fatigue analysis, ISD will perform high fidelity strength and fatigue analyses of the backbone structure to identify sufficiently robust designs of the backbone structure. To calibrate the numerical methods, experimental coupon tests of the backbone structure’s base material are scheduled to identify respective static and fatigue-related material properties. Beside the identification of mechanically robust designs of the suction panel, the numerical simulations are also to address topics like scalability of the suction concept and the benefits of thin ply laminates, which are well known to feature a superior fatigue resistance.

  Led by: Prof. Dr-Ing habil Raimund Rolfes

  Team: M. Sc. Muzzamil Tariq, M.Sc. Christian Gerendt, Dr-Ing. Sven Scheffler

  Year: 2019

  Funding: DFG, German Research Foundation

  Duration: 01.04.2019-31.12.2022
• SE2A-Excellence Cluster sustainable and energy efficient aviation

  Although the suction panel concept holds a high potential to increase the sustainability of future aircraft, it comes with some structural mechanical challenges that need to be carefully examined. With the panel’s underlying backbone structure adopting the load-carrying function of the outer airfoil in the suction area, the stress flux in the airfoil is considerably disturbed, resulting in multiple, potentially critical stress concentrations. To ensure sufficient robustness of the suction panel concept in terms of static strength and fatigue resistance, the backbone structure is to be analyzed numerically employing finite element simulations. With deep knowledge in the field of continuum damage mechanics and progressive fatigue analysis, ISD will perform high-fidelity strength and fatigue analyses of the backbone structure to identify sufficiently robust designs of the backbone structure. From the mechanical standpoint, thin-ply (TP) laminates are known to have better static strength and fatigue resistance in contrast to conventional laminates. A well-established fatigue damage model (FDM) was calibrated and modified in order to consider the influence of ply thickness under static and cyclic loading.

  Led by: Prof. Dr-Ing. habil. Raimund Rolfes

  Team: Muzzamil Tariq, M.Sc., Dr.-Ing. Sven Scheffler

  Year: 2019

  Funding: DFG, German Research Foundation

  Duration: 01.04.2019-31.12.2022