| Structural glulam and laminated veneer lumber are the main materials of modern woodconstructions and other wood building components.In order to meet the needs of structuraltimber’s carrying capacity requirements, especially giving the outermost layer laminate boardwith excellent physical and mechanical properties, laminate is a constituent unit timber whichis usually made of solid wood boards or finger splicing plate. Due to the scarcity of thedomestic natural forest timber, it has important practical significance in using plantation woodas raw material to make composite reinforced structural materials to ease the shortage ofhigh-quality timber, and promote the development of plantation.In this paper, glass-fiber fabric reinforced poplar veneer composite laminates were madein accordance with the structure principle of laminated veneer lumber, using poplar veneer asthe base material and glass-fiber fabric as reinforcing material. The main contents of this thesisinclude: structural design of composite laminates; experimental analysis of laying position andnumber of layers of glass-fiber fabric and its infulence to the properties of laminates;providing a basis for optimizing the structure of composite laminates; glass-fiber fabricreinforced composite laminates preparation and performance were to take a single factor andmulti-factor orthogonal hot glue system board tests conducted by the test factor analysis ofvariance poor and glass fiber fabric reinforced composite laminates prepared optimizationprocess; mechanics of composite materials to the laminate stiffness and strength theory,establishing poplar veneer glass fiber fabric reinforced composite laminates stiffness predictionmodel, a variety of tests on the composite laminate structure to be tested, compared to themeasured value to be investigated combined performance of composite laminates enhancementmechanism. The results are as follows:(1) The placement position of glass-fiber fabric on slab have significant effects on thebending strength(MOR) and elastic modulus(MOE) of the composite laminates. When glass-fiber fabrics are spread under the surface veneer of the composite laminates, the MORand MOE increased by32.63%and23.67%respectively compared with when they are speadon either side of the core veneer laminated composite materials. In addition, the glass-fiberfabric for static bending intensity enhancement effect is superior to the effect of elasticmodulus.(2) As for the unspread veneers, the MOR and MOE both rose with the increase of thelayers numbers of the glass-fiber fabric. Respectively, when adding2layers,4layers,6layersand8layers of glass-fiber fabric from the core to the surface symmetrically, the MOR wasincreased by43.5%,47.4%,51.7%,55.1%and the MOE was increased by29.5%,31.0%,33.5%,35.7%. The MOR and MOE increased remarkablely when laying two layers ofglass-fiber fabric. But the increase were not obvious in the process of laying from4to8layers.(3) The adhesive properties and the strength of glass-fiber reinforced composite laminateswere significantly improved by using silane coupling agent in the surface treatment ofglass-fiber. With increasing concentration of the coupling agent, the MOR and MOE ofcomposite laminates on the same hot-pressing process preparation increases gradually.(4) Hot-pressing experiments were carried on using the laminates taken from15arrangegrain veneer and3layers of fiber-glass fabric up and down. According to single factor and L9(34) orthogonal table, the results show that within the experimental factor levels, the effects ofhot-pressing process on layer board density and flexural performance under vertical load, thebending capacity of the parallel loading and horizontal shear strength were different. But theinfluence of thermal stress were extremely significant. Hot-pressing temperature havesignificant influence, in addition to the parallel loading of modulus of elasticity and horizontalshear strength under the vertical load.(5) Comprehensive analysis shows that when comparaed with the结构用单层板积材（是不是structural glulam？）, the poplar fiber-glass fabric reinforced composite laminates excelthe the requirements of GB/T20241-2006structural laminated veneer lumber highest level180E superior product requirements in their elastic modulus and other properties. When compared with the timber laminates, its structural performance exceed GB/T26899-2011Table2Structural Glulam visual grading laminate strength performance indicators at the highestlevel SZ1species group laminates Level Id elastic modulus and bending strength requirements.Even to the Japanese Agricultural Standards timber (September25,2007MAFF NotificationNo.1152) laminate strength performance standards, A species group layer (Abi Dong) anindicator of such requirements.Meanwhile, no peel appeared among different layers in the class I immersion peel test,which indicates the poplar glass-fiber fabric reinforced composite laminates have excellentdurability gluing.(6) Based on the composite laminates mechanical stiffness and strength theory, aglass-fiber reinforced poplar composite laminates stiffness model was established. The six andfive kinds of glass-fiber fabric by laying position by numbers and placement locationcomposite a orthogonal symmetric laminates. The calculation results by predictive modelformula of elasticity parallel to grain showed that the predictive value and the experiment valueof the glass fiber fabric reinforced composite laminates are basically the same. Although thereare different deviations between the two values, but the prediction accuracy are higher.Description stiffness model of a composite material of glass-fiber fabric for different groupsbillet placement position the elastic modulus of composite laminates with high reliabilityprediction.The different placement positions of the layers contribute differently to the MOE ofcomposite laminates.The higher of the elastic modulus, the farther of placement position fromthe central layer, the contribution rate is higher. In the composite laminates laying down onelayer of the same case, the glass fiber fabric elastic modulus of the composite laminates inorder contribution of type A25.58%, B type14.76%, C-type5.99%, D-type0.85%. Up anddown in the same when the composite laminates laying two layers of glass fiber fabric elasticmodulus of the composite laminates contribution E type is34.02%, F7.24%type only. As thelayers of rectangular cross-section composite laminates bending stiffness coefficients and their contribution to the cube of the distance is proportional to the surface, with a weighting factorincreases rapidly away from the surface.As for the composite laminates without glass-fiber and with glass-fiber laying above andin the bottom from1to4lays, the glass fiber fabric laminated on the composite elasticmodulus G type contribution rates were0.00%, H type25.59%, J type34.02%, K,36.59%,L-type37.09%. When the upper and lower layers of the composite lay-2to4layers, the glassfiber fabric elastic modulus of the composite laminates increase the contribution rate is notobvious, and the composite upper and lower layers2layers of laying increased only2.57%ascompared and3.07%. Therefore, when designing the glass-fiber fabric reinforced compositelaminate structure, the layer numbers of glass-fiber fabric should be properly controlled. |
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