Seminar by Assoc. Prof. Dr. Bui Quoc Tinh, Dr. Vo Duy and Dr. Vuong Dinh Chanh

At 9:30 a.m., December 27, 2024, the lectures from Assoc. Prof. Dr. Bui Quoc Tinh, Dr. Vo Duy, and Dr. Vuong Dinh Chanh take place in the Meeting Room B with detailed content as follows:

Assoc. Prof, Dr. Bui Quoc Tinh presented "Research Activities at DRICE"

Abstract:

An overview on recent research activities at DTRICE is presented, showing some potential computational models and approaches in some relevant issues. DTRICE currently focuses on three major research areas including computational biomechanics; solids and structures; and geomechanics. In particular, simulation problems pertaining to failure of structures and aorta are some that have been deeply studied and conducted at the said institute. Advanced and modern fracture models have been developed. Topology optimizations using effective techniques have also been examined. The talk highlights some major issues, and presents some interesting results obtained so far.

Dr. Vo Duy presented "Isogeometric gradient-free proportional topology optimization (IGA-PTO)"

Abstract:

The talk presents the incorporation of the effective gradient-free proportional topology optimization algorithm into the framework of isogeometric analysis. The minimization of compliance is considered, and the solid isotropic material with penalization method is used. The geometry, displacements, and density are all described by non-uniform rational B-spline basis functions. The density at an integration point is determined proportionally to its compliance. Then, the NURBS description of the density is constructed elementwise by deriving a relation between densities assigned to integration points and control points. The global NURBS description of the density for the whole domain is a blend of those from elements. Furthermore, a multiresolution scheme is presented by means of k-refinement technique to enable the efficient performance for large-scale problems. The accuracy and efficiency of the proposed algorithm are assessed.

Dr. Vuong Dinh Chanh presented "Finite Strain Smoothing Gradient-enhanced damage models: Theory and Applications"

Abstract:

The presentation focuses on the basic concepts and applications of the smoothing gradient-enhanced damage model in a variety of fracture problems. The developed damage model employs a transient anisotropic gradient parameter to reduce the spurious damage bandwidth, an inherent issue of conventional gradient-enhanced damage models. Furthermore, a smoothing stress technique is adopted to alleviate stress oscillation, which occurs when the interpolation functions for displacement and damage-driven variable are identical. With these improvements, the developed damage model offers several advantageous features: i) mesh-independent solutions, ii) the utilization of low-order finite elements, iii) the alleviation of spurious damage growth, and iv) the ability to model multiple cracks. Then, the smoothing gradient-enhanced damage model is extended to several fracture analyses, such as damage propagation in rock-like materials, thermo-mechanical fracture, and damage propagation in hyperelastic materials. The effectiveness and robustness of the developed smoothing gradient-enhanced damage model are demonstrated through numerical examples.