The combined debarking and chipping equipment designed in this study is suitable for debarking and chipping such logging residuals as small-diameter timber and wood branches. The overall design scheme of the combined debarking and chipping equipment is analyzed and the combined debarking and chipping equipment designed based on Solidworks software platform is introduced. Based on the SolidWorks Motion plugin, the key equipment for using log residue to produce high quality wood chips. Firstly, the overall design of the motion simulation of the combined debarking and chipping equipment is conducted, thereby verifying the feasibility of the design scheme.

A self-propelled combined debarking and chipping machine is studied and designed and it mainly consists of waling, peeling, chipping and auxiliary supporting devices. With a diesel generator providing power, the requirements for infeed, peeling and chipping operations are met. The machine is suited to be used in forest areas and can process small-diameter trees and logging residues into high-quality bark-free chip, which can not only save labor cost but also reduces transport cost.

Considering the each frame unit of continuous flat press machine,in which the pressure is equal, as one hot-press stage in continuous pressing,the authors take advantage of single-opening press to simulate each frame unit and study the best hot pressing technology of 3mm,5mm,12mm and 16mm thickness fiberboard by orthogonal test.The results show that the hot pressing technology of 210℃,0.8×P_2 MPa and speed 1 000mm/s is best for 3mm fiberboard;the hot pressing technology of 210℃,0.9×P_2 MPa and speed 800mm/s is best for 5mm fiberboard;the hot pressing technology of 220℃,1.3×P_1 MPa and speed 350mm/s is best for 12mm fiberboard;and the hot pressing technology of 220℃,1.3×P_1 MPa and speed 250mm/s is best for 16mm one.

According to the production situation that the pressure in one frame unit of continuous hot press was uniform,a single-opening hot press was applied to simulate the working status of different frame unit for investigating the properties of fiberboards with different thickness(7.8 mm and 10.8 mm) under two kinds of pressure curve(P1,P2).The results showed that P1 was better than P2 when thickness of fiberboard was 7.8 mm;P2 was better than P1 when thickness of fiberboard was 10.8 mm,and at this time all the properties of fiberboards which started from frame 36 under both pressure curves were in accordance with national standard of fiberboard.Moreover,the starting position of applying pressure in the whole of frame units was related to the thickness of fiberboard.The thinner the thickness of fiberboard,the earlier the applying pressure.

Acoustic emission system was used to obtain acoustic emission signals of fracture from plywood and chipboard specimen subjected by three-point-bending.Two acoustic emission signals of cumulative energy and total ring counts were used to discuss the fracture process and characteristics of plywood and chipboard.By using amplitude and RMS,the process of internal fracture formation,crack propagation,appearance of macro-cracks and rupture of plywood and chipboard was discussed with the increase of deflection.The results showed that internal damage evolution of wood-based composites could be effectively characterized by parameters of acoustic emission signals,such as amplitude,RMS,cumulative energies and total ring counts.Fracture damage occurred earlier in chipboard than that in plywood,and damage evolution process of chipboard could be divided into two stages,that of plywood into three stages.

Acoustic emission technology,as one of the new types of dynamic NDT method,was introduced in this paper from aspects of its definition,theory and characteristics as well as its application in wood industry.The research progress of acoustic emission technology in wood and wood based composite materials both home and abroad was analyzed with emphasis.It was indicated that the acoustic emission characteristic of wood and wood based composite materials could monitor the fracture initiation time of the crack tip in wood materials,the position of destructive source and the damage degree of the wood materials.It could also distinguish the different stages of damage and fracture in wood materials,which had very important significance to the safety detection of the component.Base on this,the development of acoustic emission technology in wood material science was pointed out.