Development of wooden portal frame structures with improved columns

In Japan, the lifetime cycle of most housing lasts around 20–30 years. A governing factor in this respect is poor durability due to old-fashioned use of the house. As a solution of this problem, houses can be built with a skeleton structure that allows free partition of spaces by future owners. To develop the skeleton structure effectively, multistory frames with spans of 6 to 10 m are required. For this reason, attention has been focused on the behavior of multistory timber frame structures. In this article, two types of wooden portal frame structures are proposed. Both structures have improved vertical columns with short horizontal members glued in. The aim of this study was to investigate structurally effective solutions with these types of columns. The first type of the new structure changed the location of the moment-transmitting ductile connection with the improved columns. The second type of structure used an extended panel zone. Nine portal frame specimens were tested. The stiffness values were improved by around 1.7 and 3.5 times when compared with the control, and the strength was improved by around 1.25 and 1.45 times.     

Pseudodynamic tests and earthquake response analysis of timber structures III: three-dimensional conventional wooden structures with plywood-sheathed shear walls

Pseudodynamic (PSD) tests were conducted on plywood-sheathed conventional Japanese three-dimensional (3D) wooden structures. Lateral load was applied to the edge beam of specimen structures to generate eccentricity loading. Specimens were based on a combination of shear walls with openings in the loading direction and horizontal diaphragms with different shear stiffness. The principle deformation of the horizontal diaphragm was torsion for rigid diaphragms and shear deformation for flexible diaphragms. Lumped-mass time-history earthquake response analysis was conducted on the tested structures, and additional calculations were conducted on structures with different eccentricity rates. Dynamic analyses were conducted by varying the masses and the resistance of the walls in the loading direction. The simulated peak displacement response in the loading plane agreed comparatively well with the PSD test results. The maximum displacement response on changing the wall resistant ratio showed almost the same tendency as that obtained by changing the mass ratio up to an eccentricity rate of 0.3; however, the maximum displacement response increased markedly beyond an eccentricity rate of 0.4. It was proved that the lumped-mass 3D model proposed in this study was appropriate for conducting a parameter study on the 3D dynamic behavior of timber structures.     

Pseudodynamic tests and earthquake response analysis of timber structures II: two-level conventional wooden structures with plywood sheathed shear walls

Pseudodynamic (PSD) tests were conducted on two-level timber structures with plywood-sheathed shear walls, which each had an opening of different configuration, to study the effects of the mechanical properties of the first and second levels on the earthquake response of the structure. The specimens had two-level conventional post and beam frames that were 3 m wide, 3 m deep, and 6 m high with plywood sheathings nailed on one face of the structure. The first and second levels had different opening configurations of window, door, or slit. Lateral forces were applied at the top of the first and second levels, calculating step by step the next displacement based on the North-South (NS) components of the 1940 El Centro earthquake. The test results were compared with those of the time-history earthquake response analysis using the lumped mass model and hysteresis model presented in the companion article (part I). The experimental and simulated results showed that the simulation by means of the lumped mass time-history earthquake response analysis predicted quite well the response of the first level, but tended to underestimate the response of the second level, and that the PSD tests of an individual wall system with the mass supported by that particular wall generally show a conservative estimate of the response.     

Collapsing process simulations of timber structures under dynamic loading III: numerical simulations of real-size wooden houses

In this study, we developed a new analysis method that enables numerical simulations of the collapse process of real-size wooden houses and evaluated the accuracy thereof by carrying out numerical simulations by shaking table tests. The distinct element method was adopted as the basic theory of our numerical analysis. This research is the first approach in which the extended distinct element method was used for Japanese timber post-and-beam construction. The size of the analysis model is a 5.5 m × 5.5 m, two-story real-size wooden house. The three analytical models were developed in terms of the strength of exterior mortar walls. The simulation results were compared with the shaking table test results. One of the collapsing processes of the numerical simulation corresponds well to the experiment results. Assessment of the possibility of collapse for real-size wooden houses was determined to be possible using our newly developed numerical analysis method.     

Pseudodynamic tests and earthquake response analysis of timber structures I: plywood-sheathed conventional wooden walls with opening

Pseudodynamic (PSD) lateral loading tests were conducted on conventional post and beam timber frames with plywood-sheathed shear walls to validate the dynamic model of wall panels, each with an opening of a different configuration. The lateral forces were applied step by step at the top of the wooden frames by the computer-controlled actuator, and the displacement response for the next step was computed on the basis of the input accelerogram of the 1940 El Centro earthquake scaled up to 0.4g. The test results were compared with those of the lumped mass time-history earthquake response analysis using the hysteresis model with pinching. The results of the dynamic analysis with this global model consisting of the envelope curves, unloading and reloading with pinching agreed well with the experimental results of the PSD tests of this type of earthquake record. Some parametric studies may be necessary, however, to validate the model with different earthquake records. The hysteretical parameters obtained in this study showed similar values for each of the wall panels with different opening configurations. This makes it possible to use the model and parameters for the plywood-sheathed shear walls to estimate the dynamic behavior of entire structures without conducting expensive PSD tests or shaking table tests.     

Mechano-sorptive effects in wooden material

Summary The effects on wood of simultaneous mechanical and moisture loading are studied. In order to clarify the mechano-sorptive behaviour of wood, a review of different phenomena presented in the literature is included. Based on this review a constitutive model is proposed for the case of uniaxial stress in the longitudinal direction. The validity of the model is checked independently against test results. The calculations show that the model is capable of describing the response of wood with reasonable accuracy. Simulations indicate that the response of small test specimens is more difficult to describe than that of larger beams. Some differences in behaviour are found to depend on loading mode and nature of moisture cycling. Very large and fast moisture cycles seem to give larger mechano-sorption than smaller variations. The results of the simulations show that there is a significant influence of strain on the shrinkage and swelling response.     

2009地板行业那点事

前言：2009年,对地板行业来讲,是不同寻常的一年。但究竟如何,春江水暧,企业感触最有发言权。为此,为了全景式地展现地板行业的2009年的发展态势,我们编辑部走访众多地板企业。这些企业有行业标兵,有黑马新贵,有区域强势品牌,更有新兴品牌。对于这些企业家,我们抛向了同样的采访问题。也许企业情况不一样,站在的角度不一样,我们＂回收＂的解答也不尽一致,甚至出现相左的解析。但我们在本次专题中仍然将这些声音原汁原味地收入,因为我们相信正是由于对话企业家这样的多角度、多层次、真性情的回答,客观构成了行业发展的原生态画卷。     

Hygromechanical behaviour of wooden composites

Summary The objective of this research is to study the moisture deformation of densified in technological pressing wooden composite materials. By generalizing Cosserat's couple-stress theory a structural model for determination of mid-surface strains and curvatures of composite board taking into account asymmetric structure and nonuniform distribution of moisture as well as nonlinear swelling functions of the wooden stuff and dependence of strain characteristics on moisture content is developed. On the basis of a laminate analogy the optimum flake or veneer alignment in board has been estimated for the real composite production process. According to analysis performed, the optimum alignment for hygromechanical properties may not coincide with that for mechanical properties, and for every type of loading, material with a definite structure should be used.     

木地板厂的粉尘控制研究

针对国内外对环境保护日益重视的特点,从木地板厂产生的木粉尘的特性及危害,收集和再利用3个方面简述了对木地板厂粉尘的控制。     

木本植物多倍体育种研究进展

该文论述了木本植物多倍体的特征、形成途径,展望了多倍体未来发展的方向。     

The dynamics of innovation in Malaysia's wooden furniture industry: Innovation actors and linkages

As a low-tech, labour intensive and supplier-dominated industry, the wooden furniture industry's pattern of innovation is widely acknowledged as business driven. This paper's main objective is to ascertain the roles played by the various innovation actors and their linkages to the process of technological innovations in the wooden furniture industry. Empirical evidence is derived from a narrative case study of the Muar furniture cluster in Malaysia. The main findings from this study indicate that the dynamics of innovation in Malaysia's wooden furniture industry are mainly business-led and are characterised as collective innovation. In this regard, the roles played by the immediate business environment such as suppliers, customers, competitors, and retailers are of paramount importance. These innovation actors have been linked closely to firms in their surge for technological advancement. Universities and government organisations do not feature in the operations of these firms.     

浅谈木粉燃烧机在林产工业中的应用

中密度纤维板、刨花板及木材加工生产过程中产生大量砂光粉尘、废料等。尤其是砂光粉尘,颗粒径一般在50um以下,若不合理利用,对环境污染特别严重,对能量也是一种浪费。本文介绍了砂光粉尘的产生、特性、危害及如何处理过程,并做了经济效益分析。     

木质纤维柔性地板的生产工艺

主要阐述了木质纤维柔性地板的性能及技术参数、生产工艺、市场前景与经济效益、项目产业化优势。该产品可广泛用于办公场所、公共场所及家庭住宅的地面铺装。生产过程低碳节能、对环境无污染;使用过程中无甲醛、苯等有害物质释放。其市场前景十分广阔,并具有显著的经济效益,是一种资源节约、环境友好、低碳节能的新型材料。     

浅论强化木地板的性能

随着世界人口的增长,人类文明高速发展。但人类在不断创新自己的同时,也无形中不断地在破坏大自然的资源。许多国家的资源消耗速度特别惊人,例如泰国,1961年森林覆盖率还是53％,到目前为止该国的森林覆盖率已减至25.6％,这种现象不     

防止木质卫生筷子劈头的技术措施

在卫生筷子生产中,筷子劈头对产品的等级率影响极大,直接关系到企业的经济效益。采取必要的技术措施解决这一关键问题,对提高木材利用率和企业经济效益,都具有现实意义。现将生产中总结出的实际经验介绍如下。1 木段蒸煮 蒸煮木段以使其软化是生产的首道工序,然     

木制家具机械加工中的不安全因素分析

木制家具制造是事故多发行业,其事故发生率远远高于各个行业的平均水平,家具生产事故发生的主要直接原因是人的不安全行为和＂机＂的不安全状态,由于家具机械有其独特性能,研究事故发生原因,可以减少家具生产事故的发生,减少企业的经济损失,提升企业形象,具有较高的经济价值和社会价值。     

我国木地板产业竞争力现状及对策分析

基于钻石模型从生产要素、需求条件、相关及支持性产业、企业战略结构与同业竞争、机会和政府的角度分析了影响我国木地板行业的相关因素,介绍了我国木地板行业中各个要素的优劣势,提出提升我国木地板产业竞争力的对策,为木地板产业政策制定以及竞争力研究提供参考。     

A mathematical model of mould growth on wooden material

Summary A mathematical model for the simulation of mould fungi growth on wooden material is presented, based on previous regression models for mould growth on sapwood of pine and spruce. Quantification of mould growth in the model is based on the mould index used in the experiments for visual inspection. The model consists of differential equations describing the growth rate of the mould index in different fluctuating conditions including the effect of exposure time, temperature, relative humidity and dry periods. Temperature and humidity conditions favourable for mould growth are presented as a mathematical model. The mould index has an upper limit which depends on temperature and relative humidity. This limiting value can also be interpreted as the critical relative humidity needed for mould growth depending also on the mould growth itself. The model enables to calculate the development of mould growth on the surface of small wooden samples exposed to arbitrary fluctuating temperature and humidity conditions including dry periods. The numerical values of the parameters included in the model are fitted for pine and spruce sapwood, but the functional form of the model can be reasoned to be valid also for other wood-based materials. Received 18 May 1997     

装饰用薄木材色的热响应行为分析

借助CIE的L*a*b*标准色度学系统,研究了西南桦、云南松和云南铁杉装饰薄木在热处理过程中的材色变化特征。结果表明:随着处理温度提高和处理时间延长,装饰薄木的明度下降,处理前后色差增大;西南桦材色的热响应速度更快,变色主要发生于热处理开始的15 min内,云南松和云南铁杉对热处理的响应速度较慢,160℃以上的处理色差才显著增大,明度才有显著下降。