Journal of Science and Transport Technology

Numerical study of punching shear behavior of flat slab with openings

Fri, 10 Jul 2026 00:00:00 +0000

Punching shear is a critical failure mode in reinforced concrete flat slabs, particularly when openings are located near slab–column connections, where they disrupt load transfer and intensify stress concentration. This study develops a validated nonlinear finite element model to investigate the punching shear behaviour of flat slabs with openings. The model shows good agreement with experimental results in terms of load–deflection response and failure mode, with discrepancies in ultimate load below 4%. A systematic parametric study is conducted to quantify the effects of opening location, size, and shape. The results show that openings adjacent to the column reduce the ultimate load to 166.7 kN, while increasing the distance to 50 mm and 100 mm enhances capacity by 23.86% and 24.93%, respectively. Increasing opening size leads to strength reductions of up to 12.4%, whereas circular openings exhibit higher capacity than square ones due to reduced stress concentration. The study provides a validated numerical framework and a quantitative assessment of the combined influence of opening geometry and position on punching shear behaviour, offering new insight into the governing failure mechanisms.

Thermomechanical vibration of sandwich beams with FGP core based on a Timoshenko beam formulation

Nguyen Dinh Kien, Le Thi Ngoc Anh — Sun, 05 Jul 2026 00:00:00 +0000

This paper investigates the thermomechanical vibration of sandwich beams with isotropic homogeneous face layers and a core of porous material by using a Timoshenko finite element beam formulation. The material properties of the sandwich beams are dependent on the environmental temperature, and the porosity distribution in the core through the beam thickness follows a cosine function. Applying the finite element method, a beam element formulation is derived and used to construct the discretized motion equation. The present formulation employs the solution of the homogeneous equilibrium equations to approximate the rotation and deflection of the beams, which helps to improve the efficiency and to avoid the shear-locking problem. The finding emphasizes the significant impact of the environmental temperature and the porous parameter on the thermomechanical vibration responses. A detailed investigation is presented to illustrate the effects of the temperature variations, the porous coefficient, the specific beam configuration, and the ratio of span to height of the beam on the vibration of the sandwich beams.

A Three-variable Isogeometric Model for Free Vibration Analysis of Triply Periodic Minimal Surface Plates

Thoai N. Tran, Nam V. Nguyen — Sat, 11 Jul 2026 00:00:00 +0000

Triply Periodic Minimal Surface (TPMS) architectures offer an optimal balance of minimal weight and superior mechanical resilience. Consequently, they have emerged as excellent candidates for advanced engineering applications, including aerospace and biomedical structures. To better understand their vibrational behavior, this study presents an effective framework dedicated to the free vibration analysis of TPMS-based plates. The computational model employs isogeometric analysis (IGA) in conjunction with a higher-order plate theory. This approach efficiently reduces the required independent variables to three while automatically satisfying stress-free boundary conditions. The reliability of this numerical approach is first confirmed through benchmark comparisons. Subsequently, the study investigates the vibrational characteristics of plates modeled with Gyroid, Primitive, and I-graph and Wrapped Package-graph (IWP) architectures. A key focus is placed on the impact of architectural variation. Therefore, uniform (Uni.), symmetric (Sym.), and asymmetric (Asym.) porosity distributions along the plate's thickness are systematically analyzed. The computational results indicate a profound sensitivity of the natural frequencies to both the selected porosity distribution functions and the underlying TPMS geometries. Ultimately, these findings demonstrate the critical role of these parameters in optimizing lightweight, high-performance structural designs.