Research on Bending Resistance of Plastic Wood Decking

Wood-plastic Composites (abbreviated as WPC) are made of low-value primary biomass fibers such as sawdust, bamboo chips, rice husks, wheat straw, soybean hulls, peanut shells, and sugarcane bagasse as the main raw materials.Utilizing the principle of interface fusion of polymer chemistry and the characteristics of enhanced filling modification, a certain proportion of plastic base material is mixed, supplemented by appropriate processing aids.A new material with reversible circulation and multiple uses that is processed and formed by special processes.Wood-plastic composite decking has properties such as moisture-proof, water-resistant, acid-alkali resistant, odorless, anti-fungal, anti-static, moth-proof and paint-free, and meets the comfort requirements of the human body.At the same time, it also has the characteristics of natural wood and can be provided in various colors and cross-sectional shapes according to user needs. It is a product supported and promoted by the state.

① The flexural strength of hollow plastic wood decking is the best, followed by solid boards, and the worst is open boards. Although hollow plastic wood decking has high bending strength and small strain, the hollow structure is easy to accumulate rainwater, which can cause the plastic wood in the cavity to expand and deform under a certain temperature and humidity.Moreover, the surface layer of the material is thin, and the surface is prone to wear and tear, especially after long-term use in public places.It is recommended to seal the heads at both ends to prevent water from entering, or to add drainage holes below to reduce deformation; although solid plastic wood decking is heavy and costly, it has good flexural strength;Although the open-type plastic wood deck has low bending strength and large strain, due to the existence of semicircular holes, drainage channels can be formed, and the entire board is thicker and has small expansion and deformation. Taking into account the above factors, it is recommended to add ground corrugation to reduce deformation and increase its firmness. Therefore, the decks of the three structures have practical application value and space.

② Since the semicircle is dug out of the lower part of the open-type plastic wood decking, its moment of inertia is only 59% of that of the solid board of the same specification.However, its bending elastic modulus is the largest, followed by hollow plastic wood decking and solid plastic wood decking the smallest.

③ Regarding these three special-shaped structures, the hollow type has the largest W/A and is the most reasonable, followed by the solid type and the open type the worst.

④ By reducing the semicircle diameter of the lower half of the opening of the open deck, W and A can be increased, thereby improving its bending resistance. The opening type deck with a semicircle diameter of 6mm has a W/A of 3.82, which not only saves materials. And it can meet the bending resistance requirements.