Processing Technology Of Bamboo Scrimber And OSB Composite And Its Performance Prediction

Bamboo scrimber is reorganized and reinforced by raw bamboo which is a kind of newbamboo composite. Its advantages include high utilization rate of raw materials, high strength,uniform texture, good processing performance. For a decade, china’s MOSO bamboo scrimberindustry being develop rapidly, products have been used in the field of construction,engineering, strcture etc, gradually. Meanwhile, the poplar, a important fast-growing timberresources in china, is a wonderful substitute resource to manufacture plywood, fiberboard, andparticleboard. In this paper, the idea of bamboo scrimber and OSB composite was proposed,that laminated by bamboo scrimber and OSB has been proved have a broad prospects fordevelopment, and the design construction, process, performance and application of thiscomposite were discussed. Based on the physical and mechanical properties of MOSO naturalbamboo and bamboo scrimber, the differences of micro structure and performance betweenthem were studied. The structure features and surface properties of bamboo scrimber andpoplar OSB were also studied. Based on considerations of industrialization prospect, the hotand cold pressing production processes were analyzed in aspects of process conditions andproduction cost, respectively. The combination technology and the effect of laminate form oncomposite properties were studied and the optimal factors were decided. The classicallaminated plate theory was used to established the MOR and MOE models of bamboo-woodlaminate, and the VB program was coded. The Finite element method (FEM) was used toanalysis and optimize the bending behaviors of bamboo-wood laminate, the prediction methodbased on FEM was finally obtained and the example of bamboo-wood laminate container floorwas used to tested. The main conclusions of this paper are following:(1) Vyis the fiber volume fraction of bamboo composite. The Vyvalue along the radialgradient decreases from outer to inner side. The internal construction was changed afterreforming, the bast fibers become dense near pith ring side, whose Vyvalue around50%in most area, and the value remain constant near the pith ring. After reforming, most of theparenchyma of the pores, the vessels between vascular bundlesand sieve tubes weredisappeared, the circular shape of the vascular bundle also changed to elliptic and theparenchyma were largely removed by rolling process. The density and evenness of wholestructure were improved because of PF adhesive cured as the substrate. Overall, The basicproperties of bamboo scrimber increased with the increased of density, and the magnitude ofbamboo modulus is higher than strength’s. The radial shrinkage rate greater than tangential’sand the bulk shrinkage rate of bamboo scrimber (48%compressive rate) is greater than naturalbamboo.(2) Due to the heating volatilization rate differences and the effects of extraction,carbonized process make the surface of bamboo scrimber become rough. The influence ofarithmetic average deviation (Ra) and the point height of irregularities (Rz) and maximumheight of profile (Rmax) were not significant. With the mesh of sand paper increase, sandedbamboo scrimber surface more smooth and Ra, Rzand Rmaxvalues smaller. The roughnessvalues of surface treated by sliced and100mesh sandpaper are near. In general, thelongitudinal roughness values is far less than transverse grain, the former is half of the latterunder the same measure condition. For UF, PF, EPI, PUR and water, the change rate on theouter surface and contact angle are smaller than the inner’s, the wettability of bamboo joint isweak.(3) Compare to PF heat-press process, the advantages of PUR cold-press process includefree pollution, low cost, low energy consumption and higher efficiency. For annual productionof1million m2of3-layers bamboo scrimber and OSB composite manufacture, the unit cost ofthe cold-press process lower12.52yuan than PF heat-press process. The optimum processconditions are1.5min/mm of press time,200g/m2of single gule content and1.2MPa of press.(4) To make the composite obtained higher stiffness, appropriate increase thickness andcriss-cross lay seen to be the optional way. The change of layer direction could improve thedimensional stability. For a given thickness of bamboo layer, the increase of layer does not influence the properties of composite, significantly. Add of nonwoven fabrics decrease thedimensional stability of composite significantly.(5) In terms of the end product performance, laminating with bamboo scrimber, is a kindof rational way to improve the bending properties. It is proven that the bamboo is a promisingreinforced material. The bamboo located in the surface to support the stress concentration ofthe structure, to verify the three layers of laminated structure (strong-weak-strong) is a kindof rational structure combination. The FE model can accurately predict the stiffness of laminate,and3-D model is proven more accurate than the2-D model. For strength prediction, the furtherimproved model is need.(6) The Altair Optistruct structure analysis and optimization tool are proven feasible,optimized thickness can meet the security needs of the engineering application. For3-layeredbamboo scrimber and OSB composite, compare with traditional structure, the optimized layerstructure save a third of bamboo usage.