Study On Deformation Control Of Asymmetrical Engineered Wood Flooring

In order to alleviate the imbalance between supply and demand of wood in China,increase added value of fast growing wood and utilization ratio of high quality wood,asymmetrical engineered wood flooring was developed,which took high quality wood as surface layer and fast growing wood as core layer.This structures of flooring play an important role in ecological,resource and social benefits of wood.In the process of use,no matter what kinds of asymmetrical flooring,the dimension stability and deformation resistance are the important indexes to measure the quality of the flooring.It is precisely because of the asymmetry which makes the flooring easy to warp.Warp is defined as the bending deformation of the initial flat slab,which is the prominent problem in wood processing in the wood industry.The United States Board Association believes that warping will be a leading issue in future research.This paper took asymmetrical engineered wood flooring as the research object,aiming at controlling its deformation.First,the properties of ten new wood flooring materials were analyzed,and then the deformation and moisture content of asymmetrical engineered wood flooring were simulated by the finite element method,and the tests were carried out to optimize the structure of asymmetrical engineered wood flooring.Finally,the optimized structure was obtained.On the basis of the process,the response surface method was used to discuss the effect of adhesive spread,press time and press pressure on the performance of the asymmetrical engineered wood flooring.The following conclusions are drawn:1)Studied on raw material properties of asymmetrical engineered wood flooring came to the following conclusions:The dry shrinkage coefficient of the 10 new species from small to large was as follows:BILINGA<OAK<OKOUME<KOSIPO<DIBETOU<BOMANGA<ACAJOU<SIPO<MOVINGUI<IROKO<TALI;The MOE of the 10 new species from small to large was as follows:OKOUME<ACAJOU<DIBETOU<OAK<BOMANGA<SIPO<KOSIPO<KOSIPO<KOSIPO<MOVINGUI<TALI;The order of the stress changed amount produced by unit moisture content for 10 new species was:OKOUME<OAK<DIBETOU<BILINGA<ACAJOU<BOMANGA<KOSIPO<SIPO<MOVINGUI<IROKO<TALI;When changed unit moisture content,the ratio of dry shrinkage internal stress and MOR of 10 new species,the BILINGA was the most easily deformed with the worst stability and the TALI was the most difficult to deform with the best stability.2)Through the finite element simulation analysis of the deformation and moisture change of asymmetrical engineered wood flooring under specific environment,we can concluded that the product design of engineered wood flooring was introduced into the finite element method and the ideal results were obtained by simulation test.When the thickness of the surface layers were fixed,the thicker the core layers were,the smaller the flooring deformation was,the higher dimensional stability was;When the thickness of the core layers were fixed,the thicker the surface layers were,the smaller the floor deformation was,the higher dimensional stability was.The influence of the thickness of the thickness of the surface layers on deformation of the flooring was greater than the thickness of the core layers.The asymmetrical base material can reduce the deformation of the engineered wood flooring by using different thickness of veneers.The superior structure of 6mm was 1/1/1/1/2;the superior structure of 8mm was 1/1/2/2/2,so the thick veneer was placed at the bottom of the base materials as much as possible and the deformation of the engineered wood flooring can be effectively controlled.Under the simulated environment and boundary conditions set in this chapter,the glue layer in the engineered wood flooring can play a role in the water barrier;the surface layer was greatly influenced by the moisture content and the moisture content of the internal wood varied slightly;the thicker surface layers were,the longer it can reach the environment moisture content.The simulation results were verified by the design test,which was consistent with the simulation results.It showed that the ANSYS software can be used in the structure design of engineered wood flooring and provide a more scientific test and analysis means to provide reference for the design of similar real wood composite products in the future.3)The response surface method was used to analyze the effect of cold press technology on the performance of asymmetrical engineered wood flooring.It can be concluded that the correlation between the predicted values and real values of the 4 regression models of MOE,MOR,bonding strength and deformation are 0.94,0.96,0.98 and 0.93,which indicated that the4 models had high fitting degrees.Comprehensive analysis showed that the optimized parameters of the asymmetrical engineered wood flooring were 178g/m~2,20.22s and 1.19MPa for adhesive spread,press time and press pressure.