Research On Furniture Design Strategy Based On Thermochromic Wood

Thermochromic wood is a new type of wood based on phase-changing technology.When used as furniture material,thermochromic wood can not only enrich the decorative effect of furniture,but also indicate the surface temperature of furniture,and also have the functions of heat storage and heat release.The furniture design strategy based on thermochromic wood(TW)was expounded step by step:TW was prepared in this study by directly injecting thermochromic dye(TD)into wood and combining TD with wood;According to the mechanical properties,structural characteristics,color-changing characteristics,decorative characteristics of the prepared TW,the design properties of TW was studied,and the design motivation of TW furniture was studied from the perspective of function and value;The furniture design method based on thermochromic wood,which was constructed;The design method of temperature-indicating furniture was studied,and the design verification of temperature-indicating furniture was carried out.The main conclusions are as follows:(1)The poplar-based thermochromic woods(TW-1,TW-2 and TW-3)that were prepared,and the preparation method of TW was also suitable for fraxinus mandshurica and pine.TW-1,TW-2 and TW-3 can change color from light-red to dark-red,and can produce obvious color changes at 25℃,32℃ and 42℃ respectively.Their color difference values(ΔEab)between before and after color change were over 12(the obvious visual recognition standard value).Compared with original poplar material,TW-1,TW-2 and TW-3 had better bending strength(increased by 47.16%,70.68%and 59.25%respectively),bending elastic modulus(increased by 50.00%,70.82%and 40.69%respectively)and tangential section hardness(increased by 24.03%,70.82%and 64.38%respectively);After heating,TW-1,TW-2 and TW-3 had more heat storage capacity,and the heat storage capacity of TW-3 was the best within 25 min,while that of TW-2 was the best within 40 min.TW was deeply impregnated by TD,and TW will not lose its thermochromic function after planing,milling,turning and carving in the processing process.The ultraviolet resistance,coating property,harmlessness and thermochromic mechanism of TW were also analyzed.(2)The design attributes of TW and its furniture design motivation were studied.TW-1,TW-2 and TW-3 had excellent bending strength(～100 MPa)and bending elastic modulus(～10 GPa),which were in line with the mechanical requirements of furniture components such as table top,sitting surface,cross-beam and core board.The material structure of TW basically retained the structural characteristics of the original wood,and the ΔEab of early and late wood will also increase(maximum ΔEab:22.0)or decrease(minimum ΔEab:6.2)with thermochromism in TW.The increase and decrease of ΔEab between early and late wood that can give furniture more possibilities for surface texture,the surface texture was clearer when increased ΔEab,but more subtle when decreased ΔEab.Color-changing characteristics were mainly reflected in color,temperature and time,according to its color-changing characteristics,the relationship matrix between color-changing color,temperature and time was constructed(see formula 3.1),and the overall relationship in color-changing temperature was described by set(see formula 3.2);Decorative features mainly lie in the mutual transformation between different texture features before and after color change or between different texture and color features(average colour saturation before color change:～57%,average color saturation after color change:～89%),which had the aesthetic characteristics of Technical Beauty.This studied the main factors driving TW into furniture design from the perspective of function and value.(3)The furniture design method is based on TW that was constructed.Based on the design characteristics(Dc)of TW and guided by the design drivers({Dm})from furniture function and value,the design main goal(D mg)of TW furniture components was defined.The main goal of the design focused on color-changing function or temperature indication function.Then,according to the furniture features required in the design main goal,the design sub goals({Dsg})were analyzed.The design sub goals focused on color-changing function or temperature indication function.For each Dsg,the corresponding design solution was proposed,including functional design based on design sub goal,form design based on function realization and structural design based on form realization.(4)For the Dmg of the heating table top,indicating surface temperature and heat storage,the TW-2 was made into the table top,which can remind the possible warmth for users by thermochromism phenomenon,and with good heat storage;According to the eye movement data,we studied the visual advantage of TW-2 table form.The decorative layer and its base material of the table top,were combined into a new component with temperature-indicating function and bearing capacity by using TW-2.The tensile load of TW-2 spliced specimen with tenon and epoxy resin,was 1280 N,which was higher than the requirement of 900 N in level 5 of horizontal static load test,and can completely meet the use requirements of the table top.Avoid scalding and sunburn that was the Dmg of a temperature-indicating beach chair.TW-1 and TW-3 were made into the sitting surface and backrest of beach chair.The color information of the sitting surface and backrest was collected by high-definition camera,and then the color information that can reflect scalding and sunburn,was identified by LabVIEW program.According to the eye movement data,we studied the visual advantage of the beach chair form of TW.Through ANSYS analysis of the structural strength and durability of the beach chair,which found that the maximum deformation was 0.64 mm,the maximum stress was 6.59 MPa and the minimum safety factor was 2.2(standard:1.2),the minimum service times are 2.255×105(standard:1 ×105),and the maximum fatigue damage value was 0.26(standard:1).After soaking acrylic resin-coated TW-1 and epoxy resin-coated TW-3 in water for 72 h,the moisture expansion rate was～0.1%(standard:1%under the～65%humidity for 6 h),and the thermochromic ΔEab was still greater than 12.Through the above research,the preparation technology,the thermochromic mechanism,the design attributes of TW and its furniture design motivation,which were expounded.The furniture design framework is based on TW was constructed.This work provided the reference for designing new wooden furniture.