Influence Factors Of The Strain Of The Oak Puzzle

The paper studied the oak puzzle material, and measured the strain of each specimen indicated by dynamic static stress strain gauge through strain gauge electric measurement. In this study, the relationship between the strain of specimens produced by the internal stress, and bonding pressure, rubber, raw material moisture content, splicing and the temperature was obtained by using single factor analysis, range analysis, variance analysis and stepwise regression multivariate analysis method. Through orthogonal experiment, the optima technological scheme was determined, and the multivariate statistical prediction model was established for the transverse and longitudinal strain and the influencing factors. The results were shown as follows:1) In the single factor experiment, the transverse strain of specimens was significantly greater than the longitudinal strain of the specimen; the bonding pressure, glue, water content and temperature have a significant impact on the transverse and longitudinal strain of the test piece; the splicing method had no significant effect on the transverse and longitudinal strain of the test piece. With the increase of the bonding pressure and temperature, the transverse and longitudinal strain of specimen showed an increasing trend; the transverse and longitudinal strain of specimen which prepared by using the PVAc is greater than that of specimen which prepared by using the bicomponent glue and the phenolic resin glue; in addition, the transverse and longitudinal strain of the specimen increases first and then decreases with the increase of water content.2) The bonding pressure, adhesive and moisture content were taken as reference factors, and the lateral and longitudinal strain of the oak panel were used as the index. The results of orthogonal test were analyzed by range analysis and variance analysis. The results showed that the moisture content, bonding pressure and glue species have significant influence on the horizontal and vertical strain of the plate, and the interaction between the bonding pressure and the glue have significant effect on the transverse strain of the plate. The influence degree of each factor on the transverse and longitudinal strain of the plate from large to small is:the bonding pressure, the moisture content, the sizing variety. The optima technological scheme can be obtained under the condition that the moisture content is 10%, the bonding pressure is 1MPa, and the glue is the bicomponent glue.3) By using the stepwise regression method, the stepwise regression multivariate statistical prediction model was established for the horizontal and vertical strain and the significant influence factors. The transverse strain model is:Y₁=-5850.281+65.152X₁²+560.514X₂²-211.491X₃²-1340.534X₁+818.973X₃ The longitudinal strain model is:Y₂=345.293+3.409X*12-20.463X₃²-71.27X₁+38.794X₃+42.214X₂X₃The two prediction model have passed the regression coefficient significance test, the goodness of fit test and the significant test of equation.Finally, the verification test was carried out and the average absolute error was used as the evaluation index of the model. The results show that:MAPE1=0.0452<0.1, MAPE2=0.0572<0.1,the two models have high prediction precision.Through these two strain models, the transverse and longitudinal strain values of the specimen can be predicted under different technological level. The study shows that the deformation of the Splicing board can be reduced and the quality of the board can be improved by changing the process parameters.