WOOD RESEARCH Volume 69, Number 3, 2024
RUNZHONG YU, YAN LIU, ARIF CAGLAR KONUKCU, and WENGANG HU

A METHOD OF SIMULATING SEAT LOAD FOR NUMERICAL ANALYSIS OF WOOD CHAIR STRUCTURE

This study aimed to investigate the characteristic values of the human-seat interface in a normal sitting posture, and to numerically mode the load on the chair seat for the structural design of chairs. The stress distributions and the characteristic values of seat were measured under normal sitting posture by using a human body pressure distribution measurement system considering the effects of gender and body mass index (BMI). The stress distribution on the seat was then numerically modeled using three modeling methods. The observed results and the numerical analysisresults were compared. The results showed that an inverted U-shaped pressure distribution was observed in normal sitting posture. The stress was concentrated on the ischial tuberosity with a maximum value of 0.066 MPa. The ratio of the load on the seat to the gravity of the human body weight was about 65.3%. The numerical model established using the body pressure mapping method was superior to those of the uniform load method and the standard loading pad method in terms of stress distribution, maximum stress, and contact area

WOOD RESEARCH Volume 67, Number 2, 2022
ARIF CAGLAR KONUKCU

Determination of mode I fracture behavior of southern yellow pine (Pinus taeda L.) wood using single-edge-notched bending test

The fracture behavior of southern yellow pine (Pinus taeda L.) was experimentally analyzed in the radial-longitudinal and the radial-tangential crack propagation systems using a single-edge-notched bending test method in mode I loading condition. Three fracture parameters, the initial slope, the fracture toughness, and the specific fracture energy, were determined from the obtained load-deformation curves of each test sample. The results were statistically analyzed and compared with each other using the independent samples t-test. The radial-longitudinal crack propagation system had a significantly greater fracture toughness than in the radial-tangential crack propagation system. The stiffness in the radial-longitudinal system was also significantly higher than in the radial-tangential system. It was observed that the crack growing in the tangential direction needed more energy per unit area to separate a wood sample into two halves. However, there was no significant difference between the specific fracture energy values of crack propagation systems.