Calibration and Validation of a Linear-Elastic Numerical Model for Timber Step Joints Based on the Results of Experimental Investigations

Abstract

The paper is dedicated to the numerical analysis of a single-step joint, enabling the prediction of stiffness and failure modes of both single- and double-step joints. An experimental analysis of the geometrically simplest version, the single-step joint, serves as a reference for the calibration of the subsequent finite element model. The inhomogeneous and anisotropic properties of solid timber make detailed modelling computationally intensive and strongly dependent on the respective specimen. Therefore, the authors present a strategy for simplified but still appropriate modelling for the prediction of local failure at certain load levels. The used mathematical approach is based on the linear elasticity theory and orthotropic material properties. The finite element calculations are performed in the environment of the software Abaqus FEA. The calibrated numerical model shows a good conformity until first failures occur. It allows for a satisfactory quantification of the stiffness of the connection and estimation of the force when local failure begins and is, therefore, recommended for future, non-destructive research of timber connections of various shapes.

Differential Energy Criterion of Brittle Fracture as a Criterion for Wood’s Transition to the Plastic Deformation Stage

“…These features manifest themselves at the post-peak stage of deformation due to the growth of plastic strains and, as a consequence, the appearance of an almost horizontal section on the load-displacement curve. For example, for cubic spruce specimens of 40 × 40 × 40 mm (humidity 18%) under compression along the fibers with a controlled displacement of 10 mm/min (Figure 1), experimental curves (Figure 2) were obtained (in the laboratory of the Institute of Forestry, Mining and Construction Sciences, Petrozavodsk State University), which are similar to other experimental curves of comparable tests known from the literature [30,[38][39][40]. We will analyze the behavior of wood under uniaxial compression using the plots in Figure 2 and the results of acoustic emission measurements in comparable tests known from the literature [30,33].…”

“…Regarding the validity of the simulation results, we note the following. Since we consider timber as a structure [4], it is permissible to compare the dependence according to Figure 4 with the results of tests of wooden structures known from the literature [38], according to which S secant = 123 2.73 = 45.1 kN mm ; Ŝtang = 29.6 0.38 = 77.9 kN mm does not contradict Equation ( 8) and its graphical interpretation (Figure 4), according to which the condition Ŝtang S secant = 77.9…”

“…Regarding the validity of the simulation results, we note the following. Since we consider timber as a structure [4], it is permissible to compare the dependence according to Figure 4 with the results of tests of wooden structures known from the literature [38], according to which 𝑆 . 45.1 ; 𝑆 .…”

Numerical and Experimental Analysis of the Load-Carrying Capacity of a Timber Semi-Rigid Dowel-Type Connection

“…It can be an excellent tool for the understanding of the behavior of connections in timber structures. Dobeš 2022 [ 35 ], Braun 2022 [ 36 ], and Kupniewska 2021 [ 37 ] dealt with the calibration and validation of numerical models according to experimental tests.…”

Wood-Based Materials in Building

“…An important aspect of current research is numerical modeling, which is an excellent tool for understanding the behavior of joints in wood constructions [5,6]. The numerical analysis of single-step joints, applied by Braun et al [7], made it possible to satisfactorily determine the stiffness and predict the forces at the onset of local failure of single-and double-step joints. In doing so, it was found that the prediction was more accurate for single-step joints, due to the fact that the model was calibrated for this type of joint, and that the joint itself is less susceptible to geometric inaccuracies.…”