| The honeycomb paper core sandwich wood composite board is light,environmentally friendly and low in cost,and is very popular in the furniture manufacturing industry,however,due to the low compressive strength of the core layer honeycomb paper,the mechanical properties of the sandwich composite board are low,and the strength-to-weight ratio still needs to be improved,which limits its application and promotion.This paper takes core honeycomb paper as the main research object,uses kraft paperboard instead of ordinary kraft paper to increase the thickness of the honeycomb cell wall,and introduces the V-groove folding process to produce a notch folded honeycomb paper core sandwich wood composite board;and taking the core layer kraft paperboard thickness,honeycomb unit side length,honeycomb core layer thickness,and surface plate type as the main test factors,the mechanical properties and strength-to-weight ratio of different structural configurations of the panels are studied,and the best configuration plan is obtained,and provide a certain theoretical and practical basis for the enhancement of the mechanical properties of traditional wood honeycomb paper core boards.According to the flat compression performance test of the honeycomb sandwich panel,the flat compression strength of the notched-folded honeycomb sandwich panel of various structural configurations is 0.57?2.64 MPa,and the flat pressure-to-weight ratio is 2220.36?7723.63 Nm/kg.The test analysis shows that,with other factors fixed,increasing the thickness of the honeycomb core kraft paperboard(that is,increasing the wall thickness of the honeycomb unit)and reducing the side length of the honeycomb unit can increase the flat compressive strength and the pressure-to-weight ratio of the honeycomb sandwich panel.Since the compressive strength of the surface layer is much higher than that of the core layer,the flat compression failure mode of the honeycomb sandwich panel is generally laminated collapse failure of the honeycomb core.The flat compression theoretical model of the sandwich panel is selected for verification,and the relative error between the test results and the theoretical value is within ±25%According to the bending performance test of the honeycomb sandwich panel,the static bending strength of the notched folded honeycomb sandwich panel with different structural configurations is 4.94?14.93 MPa,the bending elastic modulus is 786?1549 MPa,and the bending strength-to-weight ratio is 24625.04?42066.06 Nm/kg.The test analysis shows that when other factors are fixed,choosing a thicker surface plate with high flexural modulus,increasing the thickness of the honeycomb core layer of kraft paperboard,and reducing the side length of the honeycomb unit can increase the static flexural strength,modulus elasticity and strength-to-weight ratio of the honeycomb sandwich panel.The failure mode of the bending performance test of the notched folded honeycomb sandwich panel is different from that of the traditional wood honeycomb paper core panel.Due to the enhancement of the mechanical properties of the core layer,the damage position gradually shifts from the core layer to the surface layer,and it mainly includes four forms:core shear buckling,surface plate and core layer bonding adhesive layer rupture,upper surface plate crushing,and lower surface plate fracture.And according to the different failure modes of the honeycomb sandwich panel,the corresponding three-point bending theory model of the sandwich panel is selected for verification,and the relative error between the experimental results and the theoretical value is within 125%.According to the side pressure performance test of the honeycomb sandwich panel,the side pressure strength of the notched-folded honeycomb sandwich panel of various structural configurations is 1.93?6.10 MPa,and the side pressure-to-weight ratio is 9930.17?20573.15 Nm/kg.The test analysis shows that when other factors are fixed,the selection of a surface plate with a larger lateral pressure failure load and elastic modulus can increase the lateral pressure strength and the strength-to-weight ratio of the honeycomb sandwich panel.The failure modes of the lateral pressure performance test mainly include two types:side crushing and surface plate degumming.According to the analysis of the test results,the best configuration structure is:core layer kraft paperboard thickness 1mm,honeycomb unit side length 20mm,honeycomb core layer thickness 25mm,and surface board 5mm MDF.Its flat compressive strength and flat pressure-to-weight ratio are 0.87MPa and 3,082.23 Nm/kg;static flexural strength,elastic modulus,and bending strength-to-weight ratio are 9.00MPa,1243MPa,and 32938.51 Nm/kg respectively;lateral compressive strength and lateral pressure-to-weight ratio They are 5.43MPa and 20573.15 Nm/kg respectively.Traditional wood honeycomb paper core board(the thickness of core layer kraft paper is 0.18mm,the side length of honeycomb unit is 8mm,the thickness of honeycomb core layer is 25mm,and the surface board is 5mmMDF)flat compressive strength and flat pressure-to-weight ratio are 0.39MPa and 1618.03 Nm/kg respectively;The static bending strength,elastic modulus,and bending strength-to-weight ratio are 5.42MPa,947MPa,22781.77 Nm/kg,respectively;the lateral pressure strength and the lateral pressure-weight ratio are 3.32MPa,13599.02 Nm/kg.The comparison shows that the flat compressive strength and flat pressure-to-weight ratio have increased by 123.08%and 90.48%,respectively;the static flexural strength,elastic modulus,and bending strength-to-weight ratio have increased by 66.05%,31.26%,and 45.45%,respectively;The ratio increased by 63.55%and 51.28%respectively.This subject provides a method to strengthen the performance of the core layer honeycomb paper,thereby enhancing the mechanical properties and strength-to-weight ratio of the honeycomb sandwich panel,and to provide reference and guidance for the research on the mechanical properties of traditional wood honeycomb paper core boards. |
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