Study On Preparation Process And Sound Insulation Of Wood Damping Composites

In the interior decoration,the main wood materials are mainly used.As the requirements of indoor acoustic environment become higher and higher,there is a certain requirement for the acoustic properties of wooden materials.The density of wood materials is low,and the sound insulation performance is poor,which does not achieve the ideal sound insulation effect.In order to improve the sound insulation performance of wood materials,this study used the sound insulation mechanism of multi-layer composite materials,the sound absorption mechanism of sound-absorbing materials,and the vibration-reducing and noise-reducing mechanism of polymer damping materials.The wood materials,sound-absorbing materials,and adhesives were used.The elastic damping material is compounded in a certain form.The wood-damped sound-insulating composite material obtained has sound-insulation,sound-absorbing and damping properties.Under the condition of complex sound source,it has the effect of comprehensive noise reduction.In this paper,MDF and rubber materials were compounded with isocyanate(MDI)as adhesive.Variance method was used to analyze the effect of hot-pressing process parameters on the mechanical properties and sound insulation properties of wood-damping composites.Better hot-press process parameters.On the basis of optimized hot-pressing process parameters,the influencing parameters of the sound insulation performance of wood-damping composite materials were studied in depth.Under the premise of keeping the thickness and surface density of the composite material unchanged,the sound insulation performance of the wood damping composite material is improved by designing the composite structure.Then,the wood damping composite material was composited with the sound-absorbing material,and the“sound insulation-sound absorption-sound insulation” composite structure was applied to the wooden door to improve the sound insulation performance of the wooden door,and the sound insulation performance of the wood damping composite material was verified.The main conclusions of the thesis are as follows:(1)The hot-pressing time,hot-pressing pressure and coating amount of the preparation process have a certain influence on its mechanics and sound insulation performance.The length of the hot-pressing time affects the degree of curing of the adhesive,prolongs the hot-pressing time,and the adhesive is fully cured.The adhesive strength of the composite material is better.With the prolonged hot-pressing time,the rubber and MDF fit together more closely,and the rubber can fully exert its damping performance,thereby improving the sound insulation performance of the composite material.The hot pressure has a significant effect on the MOR and MOE of the composites.The correlation coefficient is 0.555.529.Hot pressing pressure has no significant effect on IB.When the hot pressing pressure is too large,the rubber thickness of the core layer becomes thinner,resulting in a reduction in the sound insulation of the panel by 3 d B.The amount of glue applied on the MOE,MOR,and IB was extremely significant.The positive correlation coefficients were 0.869,0.824,and 0.896,respectively.The amount of glue applied increased from 32 g/m2 to 96 g/m2,and the average sound insulation increased by 4 d B.Through analysis of variance,it was determined that the hot-pressing process parameters were hot-pressing time 10 min,hot-pressing pressure 3 MPa,and the amount of glue applied was 64 g/m2,which satisfied the mechanical properties of the plate and better sound insulation performance.(2)According to Hoff sandwich theory and equivalent parameter theory to analyze the relationship between material parameters and sound insulation performance.The sound insulation performance of the composites was tested using a small reverberation chamber-muffler box method.SPSS software was used to analyze the effect of thickness,rubber thickness,density and loss factor of the MDF on its sound insulation performance.The MDF thickness has a significant effect on the sound insulation performance of the wood damping composite.When the MDF thickness increases from 3.0 mm to 5.0 mm,the weighted sound insulation increases by 6 d B.As the thickness of MDF increases,the stiffness of the sheet increases,which suppresses the resonance of the sheet.Rubber thickness has a very significant effect on its sound insulation performance,with a positive correlation coefficient of0.979.When rubber thickness increases from 0.8 mm to 2.0 mm,its weighted sound insulationincreases by 7 d B.Rubber density has no significant effect on its sound insulation performance,rubber density increases,and weighted sound insulation of wood-based damping composite material changes little.According to analysis of variance,when the material parameters were optimized as MDF thickness 2 mm,rubber thickness 2 mm,and rubber density 2.3 g/cm3,a wood damping composite material with light weight,thin thickness and better sound insulation performance was obtained.(4)The sound insulation performance of the wood damped composite sound insulation door is better than that of ordinary wooden doors.The weighted sound insulation of wooden damped composite soundproof doors is 31 d B,while the weighted sound insulation of ordinary wooden doors is 19 d B,which is 12 d B more than that of ordinary wooden doors.