Dr. Afdhal
Assistant Professor
Research Interest:
Dr. Afdhal’s research interests include material constitutive modeling, computational mechanics, and advanced experimental mechanics.
Education
- Bachelor Degree, (2013). Aerospace Engineering, Institut Teknologi Bandung, Indonesia. Project: “Numerical simulation of Split Hopkinson Pressure Bar to measure the mechanical properties of material at high strain rate”.
- Master Degree, (2015). Aerospace Engineering, Institut Teknologi Bandung, Indonesia. Thesis: “Development of Split Hopkinson Pressure Bar to measure mechanical properties of material at high strain rates: modeling, validation, and numerical simulation “
- Doctoral Degree, (2021). Aerospace Engineering, Institut Teknologi Bandung, Indonesia. Dissertation: “Development of a high fidelity anisotropic-viscoplastic constitutive model for finite element analysis of cold-rolled sheet metals”.
Latest Publications
The dynamic behavior of the lithium-ion battery is evaluated by simulating the full battery system and each corresponding component, including the jellyroll and thin-foil electrodes. The thin-foil electrodes were evaluated using a novel design of split Hopkinson tensile bar (SHTB), while the jellyroll was evaluated using the split Hopkinson pressure bar (SHPB). A new stacking method was employed to strengthen the stress wave signal of the thin-foil electrodes in the SHTB simulation. The characteristic of the stress–strain curve should remain the same regardless of the amount of stacking. The jellyroll dynamic properties were characterized by using the SHPB method. The jellyroll was modeled with Fu-Chang foam and modified crushable foam and compared with experimental results at the loading speeds of 20 and 30 m/s. The dynamic behavior compared very well when it was modeled with Fu-Chang foam. These studies show that the dynamic characterization of Li-ion battery components can be evaluated using tensile loading of stacked layers of thin foil aluminum and copper with SHTB methodology as well as the compressive loading of jellyroll using SHPB methodology. Finally, the dynamic performance of the full system battery can be simulated by using the dynamic properties of each component, which were evaluated using the SHTB and SHPB methodologies.
An accuracy of crushing performance indicators is critical to evaluate in finite element crushing simulations particularly for the press-formed capped tubular energy absorbing structures. It is essential to select the appropriate material constitutive model and to incorporate the forming parameters into the finite element crushing model as a vital input. Hence in the present article, the influence of various material constitutive models and forming (multi-stage deep drawing) parameters on the axial crashworthiness characteristics of thin-walled capped cylindrical tubes were investigated numerically. Both forming and crushing simulations were executed by nonlinear finite element LS-DYNA® code. The forming parameters such as thickness distribution, residual stress, and effective plastic strain were mapped to a finite element crushing model of the tube. The numerical predictions of the thickness distribution and final deformed profiles of the capped cylindrical tubes are correlated with the experiments. The results revealed that the forming parameters have a substantial effect on the crushing performance of the deep drawn capped cylindrical tubes. As a result of these analyses, the thickness and strain predictions strengthens the tube and significantly influenced the crushing performance indicators such as initial peak crushing force, mean crushing force, and the energy absorbing capacity.