Seminar khoa học của PGS.TS. Đỗ Văn Thơm và TS. Nguyễn Hoàng Quân
Vào 13h30 ngày 29/9/2023, Viện IAST tổ chức buổi trao đổi học thuật tại Phòng họp C với nội dung chi tiết như sau:
PGS.TS. Đỗ Văn Thơm trình bày về "Finite element modeling of the bending and vibration behavior of three-layer composite plates with a crack in the core layer"
For multi-layered composite plates made up of different types of material components, each layer commonly has a different reinforcement angle (angle-ply). In the working process, cracking defects may appear, which also due to there being numerous layers, cracks can appear only in a certain inner layer without the surface layers being cracked. This necessitates considerable research. Therefore, this study uses the third-order shear deformation theory in conjunction with the phase-field theory to model the free vibration response and static bending of laminated composite plates with just a core layer fracture. Additionally, this is the first investigation to integrate the finite element method with phase-field theory in order to model the appearance of a fracture in a portion of the plate thickness. The phase-field variable is utilized to convert the crack to a continuous domain, which simplifies calculation; this is also a property that other computational theories lack. The results of the calculations show some surprising things that have never been seen before. For example, the length of the crack changes, but the natural frequency and maximum deflection of the plate don't change much, which makes it hard to find this kind of fault.
TS. Nguyễn Hoàng Quân trình bày về "Numerical approach to predict the flexural damage behavior of pervious concrete"
This paper aims to develop a new numerical model to evaluate the flexural damage behavior of pervious concrete from its compositions. By considering this material within the framework of the quasi elasto-brittle approach, failure is modeled by the phase field method. Then, a taking-placing generation process of the extensive Monte Carlo simulation-type was constructed to account for the statistical effect of the pervious concrete structure. Various numerical investigations have been performed using this model. First, the modeling parameters were calibrated with the threepoint bending test, then numerical-experimental correlations were well captured for both elastic and post softening regimes for the different structure sizes. Archived crack pattern analyses were used to examine the influence of the pore structure on certain values of peak load. Finally, the linear relationship between the flexural strength and the porosity was confirmed by agreement with the simulation results, which comprised of empirical references.