Experimental Investigation and Finite Element Modelling for Solid Warren Dowelled Timber Roof Truss

Abstract

Timber trusses are available in various sizes and shapes and can be placed in situ or prefabricated. Unfortunately, the usage of solid timber as a structural material is limited in Malaysia compared to concrete and steel. Hence, this research investigates the structural experimental performance and finite element modelling for solid timber Warren dowelled connections roof trusses using Chengal species. The goals encompassed assessing flexural performance, establishing a correlation between strength and stiffness, and conducting a comparative study between finite element analysis and experimental findings. The experimental research entailed subjecting a Warren roof truss constructed entirely from solid wood under four-point bending load testing. The truss exhibited a linear response during both the application and removal of the load until it reached its elastic limit. Nonlinearity, resulting from the deformation and fracturing of timber at connections, was detected when the load reached 68.88 kN, ultimately leading to failure at 182.76 kN. The displacements of different components were measured, indicating ductile behaviour and failure of the joints. The objective of utilising the ABAQUS program for finite element modelling was to corroborate the experimental findings. The first model displayed a 42.91% disparity in modulus of rupture (MOR) compared to the experimental results. By meticulously calibrating material properties, the model updating process resulted in a significant 75.23% enhancement in stress. This adjustment successfully aligned the stress values obtained from the Finite Element Method (FEM) with the experimental findings. Comparisons between the experimental and Finite Element Method (FEM) results for the Modulus of Rupture (MOR) demonstrate significant enhancement after the updating process, resulting in a decrease of ΔS from 42.91–0.036%. Direct comparison of displacement values was not possible due to substantial discrepancies. This study provides significant findings on the performance of solid Warren-dowelled timber roof trusses, highlighting the crucial role of exact calibration of material properties for accurate finite element modelling.