板式家具结构强度分析

50年代后期,Kotas对五面箱体的结构强度进行了研究,并且写了一本家具设计手册。Eckelman从板式部件的接合强度及家具的整体结构强度做了许多研究,他提出了板件的刚度与各种形式角接合变形的关系。他和Rabiej对带有横搁板和中隔板的柜体作了综合分析,得出计算公式,可用其计算三角固定一角自由条件下的柜体在受力时的变形。国内主要在家具力学性能测试方面,标准制定方面做了一些研究,在结构强度分析方面尚未进行过研究。     

板式家具熔化喷射式角接合强度的研究

通过试验对柜类家具熔化喷射式角接合与常规圆榫接合的强度进行了比较分析，并用有限元法对各种角接合的柜体在受载时的变形进行了预测。     

有限元法在实木榫接合家具结构设计中的应用

文中从实木榫接合家具节点、构件和整体框架3个层面，总结、分析有限元法在实木榫接合家具结构设计中的应用现状，并对该领域存在的主要问题及未来研究趋势进行了阐释。目前主要存在以下问题:1）未形成系统性的有限元分析方法，不同研究者之间存在较大差异；2）分析准确度不高，大多研究仅为有限元软件的模拟分析，缺乏试验验证；3）未建立合理的榫接合节点有限元模型，通常将榫接合节点视为刚性节点处理。未来研究可围绕以下几方面开展:1）榫接合节点有限元模型的建立方法及简化方法；2）实木榫接合家具疲劳寿命的有限元分析方法；3）基于有限元法的实木榫接合家具结构优化设计方法；4）二次开发，在有限元分析软件的基础上，建立实木榫接合家具结构设计模块；5）实木榫接合家具智能设计与制造系统开发。将有限元法应用于实木榫接合家具的结构设计中，将有助于实木榫接合家具的结构优化设计、智能设计与制造。     

木框斜角榫接合性能研究

在木家具结构设计中,特别是具有中国传统家具风格的实木家具结构设计中,木框角部斜角榫接合强度是人们既关注又无法回避的问题。抗拉强度和抗弯强度是衡量木框斜角榫接合性能高低的两个重要指标。笔者对三种常用的、易于机械加工的斜角榫接合试件的强度(抗拉强度,抗弯强度)进行了实验测定,并从各个方面对其进行比较、分析。研究结果表明:斜角榫接合形式,胶黏剂种类,加压时间等各个因子都不同程度地影响着木框角部接合的整体结构性能。单肩斜角明榫接合效果最好。     

板式家具结构设计有限元法研究综述

文中总结、分析了有限元法在板式家具结构设计中的应用现状，并对该领域的未来研究趋势进行了阐述。国内外现有研究主要集中于板式家具在静载荷下的强度或刚度的有限元分析，研究对象多为板式家具构件或整体，而大多忽略了节点对板式家具整体强度的影响。未来可进一步从以下几方面进行深入研究:1）板式家具节点有限元模型的建立及其简化方法；2）板式家具结构耐久性有限元分析方法；3）板式家具的整体结构优化方法；4）板式家具结构设计有限元模块的二次开发；5）板式家具的智能设计及制造系统开发。     

Optimising ash wood chairs

In Sweden, forest research has been emphasised on mainly two species of wood, i.e. pine and spruce. However, we have also a number of hardwoods which could be utilised for furniture manufacturing, cabinets etc. Nowadays, these hardwoods are a slumbering resource in our country. Most of our broad leafed species are found as small stands inside our soft wood forests and hence not utilised in the most profitable way. For example, much of our birch wood is ground to paper fibres even if it would be perfect for high valued veneer. Instead, most of our birch. veneer is imported from Finland. In order to increase the interest for Swedish hardwoods we therefore have started research in this field and have now designed a chair made of ash wood,Fraxinus excelsior. Most chairs are made up of structural elements called indetermined frames which makes it a rather tedious task to analyse the internal forces in the frame. However, by using the Finite Element Method, FEM, it has been possible to reduce this drawback. This paper shows how a chair could be analysed, and designed, by use of methods common in other disciplines than furniture manufacturing. We also present results, in the form of stress-strain diagrams, from tests made on Swedish ash.The author wants to thank NUTEK, the Swedish National Board for Industrial and Technical Development for financial support and professor Larsgunnar Nilsson who provided the FEM-program PCFEMP, which was used for all the calculations. Acknowledgement is also made to Bo Skoog who elaborated all testings of the wood specimens     

Development of test methods for wooden furniture joints

Abstract

Joints are generally the weakest part of furniture and they are primary cause of failure. To ensure durability and performance of furniture, it is important for a designer to understand the stresses acting on the joints for preparing suitable design and specification of a furniture. Since each type of joint is unique in construction, it is important to know their strength, when subjected to various stresses namely shear, bending, and tensile, by testing the joints. Since there is no established test method for joints, this study was carried out to categorize joints based on their shape, identify the stresses acting over them and develop test methods for testing furniture joints in three modes namely shear, bending, and tension, which are required for designing joints of any furniture and also provide means of comparing strength of different types of joints. Different types of furniture joints were taken for the study and were classified based on their shapes such as L-shaped, T-shaped, straight, and corner joints. Six types of jigs (one type for bending, two types for shear, and three types for tension) were designed and developed for testing the joints, in such a way that any type of joint can be tested in three modes, i.e., bending, shear, and tension using a universal testing machine. The criteria for section of jigs for performing tests on joints, based on their shape and stresses acting on a particular joint, were reported. Tests were carried out using all the six type of jigs to check the suitability of jigs and test methods developed in the study.     

CHEMICAL AND PHYSICAL CHANGES OF STEAM TREATED WOOD CHIP

High dimensional stable particlcboards could be produced by usisng saturatedsteam treated wood chip at elevated pressures.Sample Particleboards were made from woodchip of Birch(Platyphylla).The component changes of steam treated wood chip were analysedby infrared.Infrared spectra demonstrated that the hemicelluloses in steam treated chip wereless than those in untreated chip.This is one of the main reasons why steam treatment could im-prove particlcboard stability.The free radical concentration of steam treated chip surfaces wasanalysed by ESR spectroscopy.The results showed that free radical concentration of treatedchip surface was higher than that of untreated chip surface.The glueyness of chip increased andparticlcboard resin content decreased.     

我国目前家具用材及其发展趋势

家具生产原材料已从全实木时代进入了一个多种替材料与之并存的新时代。同时绿色的家居环境也要求生产“绿色家具”，随着人造板工业的发展，中密度纤维板、刨花板、集成材、人造薄木等材料将成为家具制造的主要原材料。     

用有限元法分析木材中的温度分布

在木材应用中,了解温度在木材中的分布情况,掌握木材在受热时的温度场,才能有效地控制解冻,才能对干燥和防腐问题进行深入的研究,才能合理使用建筑围护材料。近年来,随着计算机应用和计算技术的发展,用数值方法求解木材中的热传导问题将成为有效、实用的方法。在许多种数值方法中,有限差分法和有限元法是目前较为成熟和用得普遍的方法。其中的有限元法是对古典近似计算的归纳和总结,它吸取了有限差     

Assessment of the bending strength of mortise-tenon and dovetail joints in leg-and-rail construction using Klainedoxa gabonensis Pierre Ex Engl. and Entandrophragma cylindricum (Sprague) Sprague

Mortise-tenon joints for working chair construction fail under bending stresses. Dovetail joints could offer an alternative due to their resistance to bending. However, furniture joint strength depends on the design of the parts and appropriateness of the timber for the construction. Information on timber-joint design combination that would improve joint strength is lacking for most secondary timbers with prospects for joinery-making. This study assessed the bending strengths of two joint designs (dovetail and mortise-tenon) for leg-and-rail construction from Klainedoxa gabonensis (a secondary timber) and Entandrophragma cylindricum (popularly used for furniture). Dovetail joints were stronger than those of mortise-tenon. For both joints, the design with longer, wider and thicker tails and tenons [large-sized (Type LS)] was stronger than its counterpart [small-sized (Type SS)]. Joints manufactured from K. gabonensis were also stronger than those from E. cylindricum. Thus, K. gabonensis could be an appropriate material for joinery/furniture production. This would broaden the raw material base for the furniture sector. However, its working chairs designed with Type LS dovetail joints would resist bending forces better and ensure stronger furniture than mortise-tenon. To offset frequent furniture breakdown, this study provides designers with reliable information regarding joint strength from different timbers to guide selection.     

Measurement of the shear modulus of wood by static bending tests

When measuring the shear modulus of wood by static bending tests, the basic theory is dependent on Timoshenko's bending theory. The shear modulus obtained by static bending is a much smaller value than that derived by other methods. We examined the applicability of Timoshenko's theory and propose an empirical equation that can derive the shear modulus properly. Three softwoods and three hardwoods were used for the tests. First, the Young's modulus and shear modulus were measured by free-free flexural vibration tests. Then the three-point static bending tests were undertaken, varying the depth/span ratios. Additionally, the bending tests were simulated by the finite element method (FEM). The shear moduli obtained by these methods were then compared. The deflection behaviors in static bending were not expressed by the original Timoshenko bending theory because of the stress distortion near the loading point. Based on the experimental results and numerical calculations, we modified the original Timoshenko bending equation. When using our modified equation the stress concentration must be carefully taken into account.     

Stability problems in optimised chairs?

Summary Chairs and other furniture are seldom designed by help of structural mechanics and modern computers. Even if the designer uses a sophisticated CAD program, he, or she, will not use for example, finite element programs, FEM, in order to optimise the construction. Most furniture is made of wood or wood composites. Usually, structural mechanics is used for designing wood members in roof constructions and so forth. Because of the consequences of a breakdown, the allowable design stresses must be very low, about one third of the measured breaking strength. Smaller wood details could be chosen with more care and for chairs the result of a break would not necessarily lead to a disaster. However, a lot of the knowledge about how to design small wood structures emanates from the pre-war aeroplane industry. The difference between tensile and compression strength properties in wood also makes ordinary FEM programs hazardous to use because the background theory assumes that these properties are equal in magnitude. In this paper we show how to calculate the internal stresses of an undetermined chair frame and also show some material test results for Swedish alder, Alnus glutinosa.This work has been financed by NUTEK, the Swedish National Board for Industrial and Technical Development. The author also wish to thank Dr. Lars Bernspång at the Luleå University of Technology, division of structural mechanics, for invaluable help with all calculations     

基于面料熨烫胶接的木质家具饰面翻新研究

为实现木质旧家具在居家条件下的翻新改造,采用熨烫固化胶接方法用面料对桦木板表面进行饰面翻新,通过探究胶黏剂种类、熨烫温度和熨烫时间对面料翻新木材的胶合强度及耐水性的影响,得出理想的烫熨胶接工艺并将之用于木质旧家具的饰面翻新。结果表明:使用电熨斗的熨烫固化代替热压机的热压固化可实现居家条件下对木质家具的面料饰面翻新,胶黏剂种类、熨烫温度和熨烫时间对饰面翻新木材的胶合强度及耐水性有着重要影响;适当提高熨烫温度和延长熨烫时间可促进胶黏剂的固化进而确保胶合性能;在3种胶黏剂中最适于居家饰面翻新木质家具的胶黏剂为API胶黏剂。通过手工熨烫方法可实现对旧家具的个性化翻新,在避免家居审美疲劳的同时实现旧家具的再利用。     

基于拆装式结构的定制木楼梯扶手结构研究

通过对定制木楼梯扶手特点的分析,明确了可拆装定制木楼梯扶手设计的关键在于扶手部件接合方式的设计,并结合木楼梯在定制家具生产过程中存在的局限性,总结出基于拆装式结构的定制木楼梯扶手结构的设计原则。通过实际案例,对可拆装结构的定制木楼梯扶手设计进行具体分析。将可拆装的理念与定制木楼梯扶手结构相结合,以期满足现代家具定制化生产需求,同时克服了现有木楼梯接合方式安全性和美观性不强的缺陷,为现代家具结构设计与定制生产提供新思路。     

Lateral performance of a semi-rigid timber frame structure: theoretical analysis and experimental study

Semi-rigidness of the joint connections is one of the main characteristics of timber structures. The pin-joint assumption for the semi-rigid joint connections might be not conservative in the timber structural design. In this paper, structural analysis was conducted on a semi-rigid timber portal frame; the formulas were derived in terms of the internal force and the lateral stiffness, and the influence of the semi-rigid connections was discussed. Moreover, experimental tests were performed on three full-scale timber portal frames and five bolted timber connections to study the lateral performance of the frames and the moment resistance of the connections. For consistency, the connections from the portal frames and the connections for bending tests were of the same configuration. Finally, a calculation flowchart of the lateral performance on a semi-rigid frame was presented to verify the derived formulas and to show a framework of the lateral structural design process.     

杉木小径材胶拼技术

杉木小径材胶拼技术以６－１２ｃｍ的衫木小径材为原料，通过制材、胶拼、干燥和加工等工艺，生产出较大规格的板方材，可代替杉木中、大径材用于家俱、建筑等行业。     

木家具常用榫结构受力分析与计算

家具的结实与稳定程度,一直是用户选购家具时所考虑的主要因素,同时也是衡量家具质量优劣的主要标准．对家具几种常用的、易受损坏的榫接合形式在承载荷过程中所受的各类力进行了分析;并在此基础上给出了对所受各类力进行量化计算的数学模型     

中国家具产业与全球家具价值链互动分析

采集1992—2008年中国家具产业的相关数据, 计算中国家具产业销售收入环比增长率、出口额环比增长率、产业出口贡献率、产业贸易依存度等指标, 指出中国家具产业具有很强的贸易依存性的特点; 采用GL指数、格林纳韦单位价值偏差法对中国家具产业嵌入全球家具价值链情况进行分析。结论表明, 中国家具产业已基本嵌入到国际采购商价值链中, 这种驱动有着很弱的根植性, 亦具有很强的全球移动性特征, 对家具产业竞争力的提升不利。     

东巴文字在现代书房家具设计中的运用

东巴文字作为纳西族独特的民族文化,其本身所固有的特殊文化内涵以及造型特征都具有较高的艺术价值。作为一种图画象形文字,东巴文字不仅在字形结构上构思巧妙,还具有一种质朴的美感,这种构形方式是在现代家具设计中得以应用的重要依据。笔者以书房家具设计实践为例,简述了东巴文字在现代家具设计中的应用。先对每种文字元素进行概述分析,再根据文字形体的特征,运用较为恰当的处理方法,设计出适于书房家具中不同功能类型的家具产品。最后以效果图的呈现证实设计方法的可行性。通过设计案例的文字元素选取、形体造型演变以及色彩分析对比,希望能起到抛砖引玉之用,为我国的现代家具设计研究提供参考思路。