Research Of Joint Properties With Metallic Inner Threaded Nut On Cupressus Funebris Endl Furniture

Furniture made of the Cupressus funebris Endl wood is one of the important furniture in Sichuan,more and more popular.This paper researches joint properties with metallic inner threaded nut on Cupressus funebris Endl furniture.Tests physical and mechanical properties of Cupressus funebris Endl wood by the methods of national standards,discusses the effects of interference fit parameters,metallic inner threaded nut depth,metallic inner threaded nut diameter on the pull-out strength,proves the above results by finite element analysis on Workbench Analyses the effects of structural on bending strength.The conclusions are as follows:(1)In this test the Cupressus funebris Endl wood moisture content is 12.5%;the basic density is 0.61g/cm~3;cross section hardness is 5333N,tangential section hardness is4178N,radial section hardness is 4066N;MOE is 8.2Gpa,bending strength is 89.8Mpa;compression strength parallel to grain is 45.8Mpa;compression strength perpendicular to entire grain in the radial direction is 9.4MPa and in the tangential direction is 8.9MPa.(2)Interference fit parameters had significant effects on the pull-out strength.In the variable range,using y=-12.06x~2-19.584x-0.5774 to calculate pull-out strength on perpendicular to grain test,reliability was 97%;using y=-5.1932x~2-10.798x-0.2106 to calculate pull-out strength on parallel to grain test,reliability was 98%.The ultimate pull-out strength of perpendicular to grain is greater than that of parallel to grain.In actual production,it is suggested that interference fit parameters is-0.8mm.(3)Metallic inner threaded nut depth had significant effects on the pull-out strength.In the variable range,using linear y=0.386x-2.6499 calculate pull-out strength on perpendicular to grain test,reliability was 95%;using y=0.3106x-2.6603 calculate pull-out strength on perpendicular to grain test,reliability was 98%.The ultimate pull-out strength of perpendicular to grain is greater than that of parallel to grain.In the actual production process,the reasonable selection of longer nuts can significantly improve the pull out performance.(4)Metallic inner threaded diameter had not significant effects on the pull-out strength.The ultimate pull-out strength of perpendicular to grain is greater than that of parallel to grain.In actual production,it is not recommended to use larger diameter to improve the pull-out strength.(5)The finite element simulation results can prove the failure characteristics and strength change on the perpendicular to grain pull-out test results.(6)Different component form of parts effect bending strength.When the double embedded nut is used to join the tow parts,from the bending strength,tow nuts arranged vertically"T"type joint is greater than tow nuts arranged vertically"L"type joint,tow nuts arranged parallelly"T"type joint is greater than tow nuts arranged parallelly"T"type joint.In actual production.Chose proper component form can improve the bending strength.