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

OPTIMAL DESIGN OF THE TRADITIONAL CHINESE WOOD FURNITURE JOINT BASED ON EXPERIMENTAL AND NUMERICAL METHODS

In this study, computer aided technology was utilized to improve the traditional grid shoulder mortise-and-tenon joint (GSMTJ). Firstly, the traditional GSMTJ was redesigned through using separated loose tenon by the computer aided design (CAD) software called AutoCAD. And then the mechanical strengths of the traditional GSMTJs and the improved GSMTJs were compared and analyzed using the experimentally validated finite element method (FEM) based on the computer aided engineering (CAE) software called ABAQUS. Finally, the GSMTJs were further investigated from perspective of manufacturing efficiency using the computer aided manufacturing (CAM) software called JDSoft SurfMill. Based on the above simulation analysis, the improved GSMTJ was validated to be equivalent strength, high manufacturing efficiency increasing by 11.5%, low processing load ratio decreasing by 30%, as well as less wood material cost reducing by 3.6% compared with the traditional GSMTJ. The proposed improved GSMTJ was validated to be more suitable to modern wood processing machines. In addition, the methodology of combining the CAD, CAE, and CAM to wood products design was proofed efficient, economic, and feasible, and can be also used in design of other products

Deformation behavior of circular saw blades with different body structures after roll tensioning

A roll tensioning process for circular saw blades with four typical body structures was built with the finite element method. After roll tensioning, the elastoplastic deformation behaviors of the four blades were simulated and tested and the effects of roll reduction displacement on flatness were analyzed. The abilities of the blades to withstand cutting temperature load after the roll tensioning process were compared. The theoretical results showed that each of the four circular saw blades with unique body structures had different process parameters in an appropriate tensioning state. Circular saw blades with different body structures showed variation in improvements of their ability to withstand cutting temperature load after an appropriate tensioning process.

Seismic evaluation of wood frame construction based on nail connection deflection status

This paper presents a concept for a seismic evaluation method for wood frame construction based on analyzing the nail connection performance status. An empirical nail model adjusted using an energy equivalence principle is proposed and experimentally validated. Then, a pushover analysis is conducted on a finite element model of a wood frame construction with a practical configuration, and the structural performances under different seismic hazard levels are evaluated based on the indicators given by FEMA 273. With the methodology proposed in this paper, engineers are able to directly perform an effective seismic evaluation by analyzing the nail connection performance status, from which the main nonlinearity of the wood frame construction originates.

Technique to improve paint utilizing efficiency of wooden board during electrostatic spraying process

A technique to improve paint utilizing efficiency of wooden board during electrostatic spraying process was proposed. An experiment was carried out for verification of its feasibility. A finite element model for electric field between spray gun and wooden board was built by ANSYS software. Experimental results show that paint weight per square meter of wooden board surface after electrostatic spraying is increased significantly when the technique is used. Simulation results show that the electric field intensity between spray gun and wooden board is increased obviously when the technique is used.

Numerical study on effects of tenon sizes on withdrawal load capacity of mortise and tenon joint

The effect of tenon length and tenon width on withdrawal load capacity of mortise and tenon (M-T) joint was studied based on the finite element method (FEM), and the relationship of withdrawal load capacity relating to tenon length and tenon width was regressed using response surface method. The results showed that the tenon length and tenon width had remarkable effects on withdrawal load capacity of M-T joint T-shaped sample. The effect of tenon length on withdrawal load capacity was greater than tenon width. The regression equation used to predict the withdrawal load capacity was capable of optimizing the tenon sizes of M-T joint with R-square of 0.926. Using FEM can get more knowledge of M-T joint visually, and reduce the costs of materials and time of experiments.