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Panelized wall system (PWS) is an effective offsite prefabrication approach that provides higher flexibility and customization power compared to modular construction. Product platform is an industrial engineering approach that can help in managing the panels' layout and component proliferation in the effort to comply with varying design requirements. Accordingly, this paper presents the development, implementation, and validation of a new exterior panelized walls platform optimization (EPWPO) model that optimizes the tradeoff between minimizing the total fabrication cost of the panels and minimizing the resulting design deviation from enforcing common platform designs for the panels. Two new metrics were developed to quantify the two conflicting objectives of panel platform design: total fabrication cost ( TFC ) and design deviation index (DDI). New computational algorithms were developed to automate the functions of panel elements geometry manipulation, structural analysis, and structural design in conjunction with the optimization process. The performance of the EPWPO model was illustrated using an application example of the fabrication of the exterior wall panels of a public school. Two analyses were performed to investigate the dependence of the model results on the platform configuration input and the degree of wall length tolerances. [ABSTRACT FROM AUTHOR]

Perforated wooden panels are typically utilized as a resonant sound absorbing material in indoor noise control. In this paper, the absorption properties of wooden panels perforated with tiny holes of 1-3 mm diameter were studied both experimentally and theoretically. The Maa-MPP (micro perforated panels) model and the Maa-Flex model were applied to predict the absorption regularities of finely perforated wooden panels. A relative impedance comparison and full-factorial experiments were carried out to verify the feasibility of the theoretical models. The results showed that the Maa-Flex model obtained good agreement with measured results. Control experiments and measurements of dynamic mechanical properties were carried out to investigate the influence of the wood characteristics. In this study, absorption properties were enhanced by sound-induced vibration. The relationship between the dynamic mechanical properties and the panel mass-spring vibration absorption was revealed. While the absorption effects of wood porous structure were not found, they were demonstrated theoretically by using acoustic wave propagation in a simplified circular pipe with a suddenly changed cross-section model. This work provides experimental and theoretical guidance for perforation parameter design. [ABSTRACT FROM AUTHOR]

The break-out sound from a cavity via an elastically mounted panel is predicted in this paper. The vibroacoustic system model is derived based on the so-called spectro-geometric method in which the solution over each sub-domain is invariably expressed as a modified Fourier series expansion. Unlike the traditional modal superposition methods, the continuity of the normal velocities is faithfully enforced on the interfaces between the flexible panel and the (interior and exterior) acoustic media. A fully coupled vibro-acoustic system is obtained by taking into account the strong coupling between the vibration of the elastic panel and the sound fields on the both sides. The typical time-consuming calculations of quadruple integrals encountered in determining the sound power radiation from a panel has been effectively avoided by reducing them, via discrete cosine transform, into a number of single integrals which are subsequently calculated analytically in a closed form. Several numerical examples are presented to validate the system model, understand the effects on the sound transmissions of panel mounting conditions, and demonstrate the dependence on the size of source room of the "measured" transmission loss. [ABSTRACT FROM AUTHOR]

The reinforcement of solid wood and wood-based composite materials is not a new idea, but there have been very few studies about reinforcing poplar plywood with glass fiber fabric using phenol formaldehyde. In this study, plywood panels were produced using poplar veneer and phenol formaldehyde adhesive and glass fiber fabric. One control group and three different test groups were set up. In addition, perpendicular and parallel test samples for each group were set up for bending tests. Some of the physical and mechanical properties of the reinforced plywood were determined using various tests. The results of the testing indicated that the plywood that was reinforced with woven glass fiber had a significantly increased modulus of rapture and modulus of elasticity of perpendicular samples. It was determined that density of the plywood was increased in the test groups. Thickness swelling and water absorption decreased for the test groups in which the plywood samples had woven glass fibers bonded onto in their surfaces. In the bending tests, the reinforcement provided by the glass fiber fabric decreased the inequalities between the parallel and perpendicular samples. [ABSTRACT FROM AUTHOR]

Wooden artefacts, wood painted panels and historic furniture represent a significant part of our cultural heritage. Their preservation over time is a challenging task, and insect infestation still represents a primary cause of loss of cultural heritage artefacts. Anoxic conditions have proved to be effective in pest control and have been extensively applied to the management of museum collections. The present work reports on the evaluation of the effects and harmfulness of nitrogen-based anoxic treatment on different wood species with or without superficial finishings. Specimens were prepared in order to be representative of various surfaces of cultural heritage objects. A complete monitoring of the treatment effects was performed by means of a multianalytical approach. FTIR spectroscopy in the MID-IR and NIR regions was conducted to assess the absence of chemical alterations, and the results were subjected to chemometric treatment by multivariate analysis. Colorimetric characterization of the surfaces was performed to monitor any undesired colour change induced by the conservation treatment. The absence of superficial mechanical damages was evaluated by means of optical and scanning electron microscopy. The results confirmed that the anoxic procedure is not harmful to the treated surfaces with respect to aesthetic, chemical and microstructural considerations, even when the most stressful conditions are applied. As wood permeability is an important parameter in order to plan an effective intervention, in this study, a simplified method to estimate the permeability of wood to oxygen in different conditions was tested. [ABSTRACT FROM AUTHOR]

A reliability analysis of roof sheathing panels was performed to assess the current minimum requirements specified in the National Building Code of Canada (NBCC). The present analysis considers the variations in the annual, hourly-mean wind speeds in cities across Canada, the external wind pressures due to roof shape, roof slope, eave height and upstream terrain, the internal wind pressures, for the range of fasteners typical of current construction practice. It was found that the use of 6d (51 mm) common nails with 300 mm spacing on intermediate supports, which is the minimum requirement of NBCC, is not adequate for many regions of the country. It was found that relatively small differences in fastener size result in large differences in roof sheathing performance. Recommendations for revisions to NBCC are made, which involve using 8d (63 mm) nails, with 150 mm spacing on intermediate supports. [ABSTRACT FROM AUTHOR]

World production of wood based panel has grown from 63,1 million cubic meters in 2005 to 75,5 million m³ in 2009, a 12 million m³ rise in production. China is the world's largest wood based panel's manufacturer. The Turkish wood based panels industry has shown a tendency of fluctuating during this time. Turkey, as the world's 4th largest producer of wood based panels, is an important contributor to the industry. Turkey has made great strides in the last 20 years in the forest products industry. Both the development of new materials and techniques of domestic and international market demand have played a decisive role. Turkey's wood panel production has gone from 100000 m³ in the early 2000s, to 5,5 million m³ of production in 2010. The sector's total production capacity is approximately 9 million m³. The results obtained thus far indicate that the Turkish wood based panel industry demand for raw material is not being met by the GDF's chip wood fiber production. Where the raw material supply problem in the industry, as well as the problems encountered in the forest and on the basis of the villagers living adjacent to, not to the time of product problems related to storage and transportation of raw materials and other related problems are bottlenecks. We examine problems related to the provision of raw materials and raw materials research, the need for future estimates of the level at which the world and close to the periphery countries will be examined, wood composite panel production and trade policy recommendations will be developed. [ABSTRACT FROM AUTHOR]

This work examines the performance of three formaldehyde scavengers in wood-based panels. Sodium metabisulfite, ammonium bisulfite and urea were applied in different physical forms during particleboard production, and the resulting physico-mechanical properties (internal bond strength, thickness swelling, density and moisture content) and formaldehyde emission levels were compared. Formaldehyde content was measured using the perforator method, and formaldehyde emission was evaluated both by desiccator and gas analysis methods. The chemical reactions involved in each formaldehyde scavenging process are proposed and discussed. The tested scavengers showed distinct performances under the different emission testing conditions, which were interpreted in terms of the stability of the chemical compounds formed upon formaldehyde capture. Sodium metabisulfite proved to be an excellent scavenger for all formaldehyde methods allowing the production of particleboard panels with zero formaldehyde emission. [ABSTRACT FROM AUTHOR]

The industrial manufacturing of wood-based panels has become a highly technological process, where all parameters have to be perfectly adjusted to manufacture products of high quality. However, variations caused by differing wood characteristics as well as variations of single process parameters can cause out-of-control events. These undesirable events can be diminished by monitoring and controlling the entire manufacturing process using multivariate statistical techniques. Hence, a real-time process adaptation of an industrial scale fibreboard manufacturing process was simulated. Regression results revealed a mean normalised root mean squared error of prediction of 4.6 %, when predicting the internal bond strength of fibreboards. The regression model is regularly validated and, if necessary, recalibrated using the offline determined board properties (feedback control). Consequently, the process can immediately be adapted as soon as the board is produced (feedforward control). The investigations resulted in reliable models and revealed high potential for permanent industrial implementation. [ABSTRACT FROM AUTHOR]

The air-coupled ultrasonic inspection method is a widely applied non-destructive measuring technique in the wood-based panel industry. The technology is mainly applied to detect panel delaminations by analyzing the transmitted signal. Recent research deals with the use of ultrasonic techniques not only for the qualitative but also for the quantitative characterization of wood-based panels. To achieve a fundamental understanding of the behavior of ultrasonic waves in wooden panels, it is necessary to study the mechanisms that affect ultrasonic transmission and velocity during testing. Impedance and attenuation effects have been examined in previous studies. This article focuses on the interferences of ultrasonic waves. The interferences can be detected in experiments where the ultrasonic transmission is tested against the panel thickness. The results are verified with a mathematical model that explains the interferences due to multiple reflections inside the tested panels. By fitting the experimental data to the model predictions, the ultrasonic velocity and attenuation can be determined. So far, interference effects have not been considered for the non-destructive testing of wood-based panels. This research is a contribution to a better understanding of the mechanisms influencing the air-coupled ultrasonic methods. [ABSTRACT FROM AUTHOR]

The paper presents the quantitative assessment of the surface quality in case of new structures (decorative) of panels obtained from finger-jointed panels made of mixed wood lamellas. The particularity of the research is that the assessment of the quality is made on the cross-cut section of the wood lamellas. Consequences of using some of the actual composite materials have occurred because of the binding materials properties, namely the formaldehyde emission, which has proved to be dangerous for health. On the other hand, the behavior of some of these materials in aggressive environment has been proved to be unsatisfactory and of a reduced durability. In order to scan the topography of the panels' surfaces, the contact-less method was used to analyze the representative roughness parameters of wood: Ra, Rz, Rk, Rpk and Rvk. The measurements were performed in the frame of the Laboratory of Testing the Processing Accuracy in Wood Industry. The present paper is an experimental study that focuses on the evolution of surface quality in case of mixed decorative panels, made of wood lamellas randomly arranged in the structure of the panels, having the crosscut section on the panels' faces. The grit sizes used for sanding operation are the most usual ones for a technological process, namely 80, 100 and 120 ones. [ABSTRACT FROM AUTHOR]

Abstract: The concept of moisture buffering value based on material level tests has been widely adopted in current room level moisture buffering studies. However, the characterization of the material buffering properties may not be directly representative of the material buffering performance at room level because the room factors influence the moisture behavior of the materials. The moisture buffering is a dynamic moisture interaction process between the indoor humidity air and the hygroscopic finishing materials. The buffering effect is the amount by which the variation of the indoor humidity is dampened both by the hygroscopic materials and by the room factors. Hence, the magnitude of the buffering effect is related to the characteristics of the building structure. This paper presents an experimental study on the moisture buffering performance of wood paneling at room level and its buffering effects on the indoor environment. The data presented include the buffering effect values of several test scenarios on a full scale test hut in a large-scale environmental chamber. The data analysis shows that the moisture response of the hygroscopic material at room level varies in different test scenarios. This variation is influenced by room factors, including ventilation conditions and the amount of moisture generation, and to a lesser degree by the indoor initial humidity conditions. Hence, the buffering effect cannot be predicted based on the material performance alone. [Copyright &y& Elsevier]

Abstract: An original analytical model to study the non-linear flange curling in wide single-flange panels is presented in this paper. Flange curling phenomenon is the tendency of the wide thin flanges (in compression or tension) to move towards the neutral axis, when thin-walled members are subjected to bending. Despite the simplicity of the formula developed in earlier works of Winter to account for the flange curling effects, which is used in current steel codes, recent work has showed that this expression is rather restrictive and does not apply for all cases. The analytical expressions reported here are rather general since they (i) consider the restraining effect provided by the web, (ii) account for the shift of the neutral axis due to curling, (iii) incorporate the decrement of the second moment of area due to curling, and (iv) are fully analytical, thus avoiding iterative techniques. The analytical model is applied to study the curling behaviour of profiled steel decks and cassette-wall panels and is validated by means of comparisons with experimental results available in the literature. Since the EC3 rules state that the tensioned wide flange in liner trays should be reduced if the curling displacement is higher than 5% of the web height, approximate expressions to evaluate the reduced width of the wide thin flange under curling are proposed. [Copyright &y& Elsevier]

A composite panel consisting of polyurethane foam core sandwiched between two carbon fiber-reinforced polymer (CFRP) skins is investigated in one-way bending. While most studies on sandwich panels are typically geared towards aerospace applications, to the authors' knowledge, this is the first study on application in cladding of buildings. Ten panels were tested to investigate their structural performance and failure modes. Test parameters include consistency of quality and performance, moment-shear ratio, moisture absorption and orientation of architectural masonry-like coating. The panels were 14 times lighter than conventional reinforced concrete panels of equivalent strength and stiffness. The study showed that design is stiffness driven as deflection limits in service will likely govern. Shear deformations of core may have a significant contribution to deflections. Most common failure mode was outward buckling of CFRP skin. Some panels failed by shear in the foam core, and in one panel, CFRP skin crushed. When the masonry-like coating was positioned in compression, it forced a shear failure but when located in tension to simulate wind suction, skin buckling occurred at lower load. While this study showed excellent potential for this novel cladding, it is recommended to laminate FRP layers to prefabricated solid foam cores, rather than injecting liquid foam in between FRP skins, to improve quality control during fabrication. [ABSTRACT FROM AUTHOR]

Abstract: Thin, profiled steel sheets forming the skin of concrete-filled composite wall panels and similar members benefit from the unilateral (tensionless) restraint provided by fill of sufficient elastic modulus. This paper investigates the buckling of such skin sheets in panels subjected to compressive or shearing loads. The profiled skins are modelled as infinite, thin orthotropic plates resting on tensionless rigid foundations, allowing the local buckling response to be simulated by the single-wave buckling mode of an unrestrained plate section of appropriate aspect ratio. Solution of the governing differential equations leads to the determination of the plate buckling coefficients. Simplified formulas for the buckling coefficients in terms of the parameters describing the skin sheets are developed and shown to agree well with published results and finite element analyses for particular limiting cases. [Copyright &y& Elsevier]

The characterization of low frequency sound transmission between two rooms via a flexible panel is investigated experimentally in this work. Previously, the individual effects of the transmission suite on the measured sound reduction index have been studied analytically, and the results have been compared with the ideal case of having free field radiation conditions on both sides of the panel. A new approach is proposed using a near-field array of loudspeakers driven by a set of optimized signals such that a diffuse pressure field is reproduced on the surface of the partition to be tested. The practical effectiveness of this method is assessed when using a set of 16 acoustic sources located in the source reverberant room in close proximity to an aluminium panel. The experimental results obtained confirm the dependence of the characterized sound reduction index on the particular test chamber considered in the low frequency range. They also validate the proposed synthesis method for providing an estimate that only depends on the properties of the partition itself. [ABSTRACT FROM AUTHOR]

The indoor relative humidity in dwellings and offices is an important factor in building physics. The ability of hygroscopic materials and especially wood materials to store and release moisture helps to regulate the indoor climate naturally and to avoid extremes of humidity. In the present study, cyclic sorption experiments with coated Scots pine were performed. Materials with different coating compositions were exposed to day-to-day relative humidity changes. The moisture buffering capacity was estimated by a gravimetric method and the moisture buffer value was computed. The results show that the coating has a significant impact on the moisture buffering capacity of the underlying Scots pine. The moisture distribution in the wood sample was appraised for each coating system using a proton magnetic resonance imaging technique. This study confirmed that the dynamics of moisture exchange between the indoor environment and the wooden material during typical daily moisture fluctuations is confined to a few millimetres behind the air-wood interface. [ABSTRACT FROM AUTHOR]

Abstract: A novel Trombe wall with PV cells is presented in this paper. A two-dimensional model of PV glass panel and a model of the PV-Trombe wall system are established. The temperature distribution and electrical performance of the PV-Trombe wall system are also obtained. Results show that according to the measured weather data and the special simulation condition, the temperature difference between the elements with and without PV cell on the glass panel reaches a maximum value of 10.6 C; the temperature difference between the room with and without PV-Trombe wall reaches a maximum value of 12.3 C during 3 days; after 7 days’ operation, the all-day temperature of the room with PV-Trombe wall retains at about 13.4 C and an increase of 5.00% for the electrical efficiency can be achieved. [Copyright &y& Elsevier]

Abstract: Swelling stresses play a significant role in the efficient use of wood products in different applications such as paneling. The main objective of this study was to investigate development of swelling stresses in the tangential direction in spruce (Picea abies) as function of water soaking time in order to provide basic data. Experimental results were compared to the theoretical calculations obtained from different models. On the basis of the findings of this study it appears that the magnitude of the swelling stresses in spruce samples in the tangential direction was approximately 1.2MPa. [Copyright &y& Elsevier]

Fuselage panels are commonly fabricated as skin–stringer constructions, which are permitted to locally buckle under normal flight loads. The current analysis methodologies used to determine the post buckling response behaviour of stiffened panels relies on applying simplifying assumptions with semi-empirical/empirical data. Using the finite element method and employing non-linear material and geometric analysis procedures, it is possible to model the post buckling behaviour of stiffened panels without having to place the same emphases on simplifying assumptions or empirical data. Investigation of element, mesh, idealisation, imperfection and solution procedure selection has been undertaken, with results validated against mechanical tests. The research undertaken has demonstrated that using a commercial implicit code, the finite element method can be used successfully to model the post buckling behaviour of flat riveted panels. The work has generated a series of guidelines for the non-linear computational analysis of flat riveted panels subjected to uniform axial compression. [Copyright &y& Elsevier]

The drivage of the supply gate of a development panel in the presumed low stress zone adjacent to the loader gate of an excavated panel with a very small width of intervening pillar between the two entries, known as skin-to-skin working, resulted in an extensive fall of the supply gate roof at a UK coal mine, Bilsthorpe colliery in 1993. This fall left a question over the application of skin-to-skin drivage of gate entries supported primarily by rock bolts. To investigate the possible reasons behind this fall, both physical and numerical modelling studies were carried out. Physical and numerical models were successful in demonstrating the potential danger of the working method with the rock bolt support system employed. Development of a shear failure plane from the rib edge into roof strata of the loader gate and development of the second shear failure plane at the abutment side of the supply gate exposed the supply gate to the fall of large rock blocks released by shear failure zones. Models demonstrated that the fall of the supply gate roof was not due to the inability of the rock bolts to prevent bed separation, but it was the method of working that made the bolts ineffective due to the height of the block delineated by the shear failure planes. Further physical and numerical models were undertaken to investigate the influence of 5, 7.5 and 10 m wide intervening pillars between the entries on the stability of the rock bolt supported supply gate roof. These studies showed that a 7.5 m or 10 m wide pillar would have prevented development of failure zones and fall of the roof while a 5 m pillar was found to be an undersized pillar width causing the development of extensive failure zones in the roof. [ABSTRACT FROM AUTHOR]

This paper provides insight to the background of the development and requirements for panel-zone design in the 1986 AISC LRFD specifications. In particular, two criteria for the design of beam-column panel zones are discussed; the first method is based on the von Mises first-yield criterion for the panel-zone web, and the other utilizes the postyield shear resistance of the panel derived from the flexural resistance of boundary elements surrounding the panel-zone joint. The nonlinear behavior of a moment-resisting frame with panel-zone joints designed according to these two requirements is studied. Lui's 1985 rigorous second-order elastic-plastic hinge analysis is used to assess the performance of a frame considering panel-zone deformations. An advanced analysis technique based on a notional-load plastic-hinge approach is introduced. This advanced analysis technique is used to evaluate the proper design criteria for panel-zone joints in moment-resisting frames, and to study the influence of panel-zone deformations on the frame's limit of resistance. From these studies, the effects of the panel-zone deformations on the overall frame resistance can then be summarized and discussed. [ABSTRACT FROM AUTHOR]