Board Thickness Research Articles

A study on a micro perforated panel applied luggage board design for road noise reduction

The automotive industry is on the age of rapid transformation from internal combustion engine vehicles to electric vehicles powered by motors. The main source of noise in conventional internal combustion engine vehicles is the engine, while electric vehicles are mainly affected by road and wind noise. A road noise in the medium and low frequency bands, caused by friction between tires and road surfaces, can be improved by increasing the thickness and weight of the insulation material. Still, this countermeasure causes other challenges that related to driving efficiency decrease because of limitations space and weight. As a new method to reduce road noise, therefore, the study introduces the luggage board which applied the micro-perforated panel system. This system utilizes a resonance-type sound absorbing material with excellent sound absorption characteristics at specific frequencies so that a tire pattern noise within the 800-1,000 Hz could be reduced. Because the thickness of the luggage board is partially limited, the study set a number of variations such as changing the porosity, perforated diameter in the perforated panel system. As a result, the study confirmed 2% improvement A.I. (Articulation Index) in the interior with installation of the designed luggage board on the vehicle.

Study on Joint Model Simplification for Finite Element Analysis of Bamboo/Wood-Oriented Strand Board Furniture.

Board furniture's performance and scientific design are making it popular. Research on simplifying furniture joints reduces design cycles and costs and improves structural safety. In this article, using a cantilever beam to calculate deflection theoretically simplifies the L-shaped component model and yields a joint elastic modulus formula. Finite element analysis (FEA) confirms the effectiveness of this simplified model by comparing its results with experimental data. In simplified components, the joint elastic modulus increases with length (l2) and stabilizes at l2/b ≥ 6 (b is the board's thickness). The variation pattern of the joint elastic modulus equals that of the stiffness, proving its usefulness in assessing component deformation resistance. Furthermore, the component strength and stiffness are also affected by the screw spacing and connector type. In particular, the connectors type affects bamboo-oriented strand board (BOSB) component performance more than wood-oriented strand board (WOSB). Compared to WOSB, BOSB components have superior strength and stiffness and are more stable. The recommended screw spacing for L-shaped components is 48 mm. BOSB components fixed with two-in-one and metal nuts utilizing threads embedded in the board have better strength and stiffness, while for WOSB components, nylon nuts, and wooden dowel pins are more appropriate for securing.

Transient temperature analysis and engineering application of steel shell immersed tunnel protected by fireproof board

Based on the Shenzhen-Zhongshan Link, the transient analytical solution of the steel shell immersed tunnel under the protection of fireproof board was deduced and verified through fire test. Then, the variation of the maximum temperature of the bottom steel shell with the thickness and thermal conductivity of the fireproof board was analyzed and suggestions on the selection of fireproof boards were given. Finally, a fitting formula for the maximum temperature of bottom steel shell was proposed. The results show that: (1) When the thermal contact resistance of the steel-concrete interface and the thermal resistance of cavity are 0.01 m2 °C/W and 0.02 m2 °C/W respectively under the case of 25 mm thick fireproof board, the variation of the analytical solution is consistent with test results, and the peak value is similar. (2) Based on the three-dimensional diagram of d -λ-T, with 300 °C as the fire resistance limit of structure, the range of the fireproof board parameters is obtained: when λ reaches 0.14 and 0.4 respectively, d shall not be less than 10 mm and 28.38 mm (3) The scatter points obtained from analysis were fitted using quadratic polynomials and linear functions respectively. Considering the accuracy and simplicity, the linear fitting formula is given as T = 275.66–7.41*d+644.6*λ.

Slip modulus of inclined screw connectors in glued laminated bamboo and wood-concrete composite beams

ABSTRACT The existing research has predominantly focused on the shear behavior of inclined screws in wood-concrete composite beams. However, there is a significant research gap regarding the slip modulus of inclined screw connectors in glued laminated bamboo and wood (GLBW)-concrete composite beam. To address this gap, nine groups of shear tests were performed to study the load-slip behavior of inclined screw connectors in GLBW-concrete composite beams. This study analyzed the impacts of screw embedding length, screw diameter, screw embedding angle, and bamboo board thickness on the slip modulus of inclined screw connectors. The results showed that in comparison to inclined screw connectors with a 90 mm embedding length, the slip modulus of screw connectors with 110 and 130 mm embedding lengths increased by 11% and 19%, respectively. As the screw embedding angle decreased, the slip modulus of inclined screw connectors increased. For bamboo thicknesses of 30, 60, and 300 mm, the slip modulus of inclined screws was improved by 40%, 78%, and 89%, respectively, compared to the screws in pure wood beam. This study presented an analytical model for predicting the slip modulus of inclined screws in GLBW-concrete composite beam based on the layering method and elastic foundation beam theory.

Acoustic characterisation of boards manufactured with fruit stones mixed with coconut fibre

Sustainable and recycled materials are being used in a wide range of fields to solve a waste management problem and, at the same time, to confer them a second life. These materials include fruit stones of different crops: apricot, peach, cherry and olive. Employing fruit stones as acoustic materials contributes to minimise the environmental impact and to create a new product with interesting sound-absorption properties, apart from offering aesthetic added value. Some previous works have demonstrated the application of fruit stones panels as sound absorbers. This study aims to determine the acoustic properties of boards manufactured with a mixture of the four above fruit stone types. A coconut fibre layer is added to compare the results with and without coconut fibre. The experimental results show that acoustic properties improve by increasing board thickness and the sound-absorption coefficient is higher when a coconut fibre layer is added. Sound transmission loss is not significantly affected by adding the coconut fibre layer.

Flexural performance of innovative thin-walled steel–timber composite floor slabs

A floor slab carries and distributes the floor load in a structure and is an important component that affects overall structural performance. Therefore, it is important to investigate the mechanical properties of such materials. In this study, flexural performance tests under static load are conducted for an innovative thin-walled steel–timber composite floor slab, and the failure mode, bearing capacity, stiffness, deflection, and strain development are investigated. The results show that the floor slab can be quickly assembled using self-tapping and wood screws and exhibits good flexural performance. Using ABAQUS finite-element software, the effects of the oriented-strand board (OSB) thickness, thin-walled–steel-plate height, steel strength, and boundary conditions on the flexural performance of composite floor slabs are investigated. Furthermore, based on the EN1995–1-1 code and equal-section conversion principle, the simplified beam-unit model is established for the theoretical calculation of the composite floor slab. The effective bending stiffness is calculated by considering the influence of the slip modulus of the connector, and the stress distribution law of the section is analysed. The results provide a reliable design basis and reference for the application of thin-walled steel–timber composite floor slabs in engineering practice.

Development of micro dust reinforced composite for building applications

Recycling and reuse of textile waste is a proficient solution in preventing waste going into landfill and causing pollution. This paper reports the use of microdust generated from fibers in textile spinning mills to fabricate composites using compression molding for prospective applications in the building sector. Ten composite samples of 6 mm and 10 mm were developed by changing the microdust-resin blend proportions ranging resin content of 30%–10%. The tensile, flexural and compression properties, fire retardancy, water absorption and the insulation properties of the composites were determined. The results showed that the 6 mm thick composite board with 70% microdust had the most desired mechanical properties with tensile strength of 6.41 MPa, compressive strength of 3.6 MPa, and flexural strength of 10.2 MPa. These properties are superior compared to commercially available false ceiling board made of gypsum material of similar density and thickness. The thermal insulation value was 0.117 m2 K/W which is equivalent to the commercial sample (0.102 m2 K/W) used in similar applications in the building industry. The sample with 80% microdust (10 mm thick) achieved the highest thermal resistance (0.1879 m2 K/W) which is about 50 % higher than a commercial sample of the same thickness. This study shows that the composite panels overall are comparable to the commercially available panel used in the building industry and provides cost effective and sustainable alternatives for thermal barrier panels while overcoming the issue of landing filling of microdust from the spinning mills.

Characterizing eco-composite boards with non-woven polypropylene from disposable face masks and bamboo reinforcement

This study investigates the development of eco-composite panels using treated and untreated nonwoven polypropylene (PP) extracted from disposable medical face masks, reinforced with bamboo particles. Treated PP underwent a washing process with detergent. Panels were fabricated with varying PP-to-bamboo particle ratios of 100:0, 75:25, and 50:50. Fourier-transform infrared (FT-IR) spectroscopy analysis indicated minimal impact of washing on the intrinsic properties of the PP material, as confirmed by thermogravimetric analysis (TGA). Both analyses showed similar intensities of functional groups and thermal trends in treated and untreated recycled PP (rPP) samples. Energy-dispersive X-ray spectroscopy (EDX) confirmed the uniform integration of bamboo particles within the PP matrix by detecting silicon and potassium elements. Chemical interactions between bamboo fibres and the PP matrix were also evident in the form of reduced peak intensities in FT-IR spectra. Despite these interactions, limited adhesion between bamboo fibres and the PP matrix led to reduced stability and mechanical strength in the eco-composite panels. A direct correlation was observed between board thickness and the proportion of bamboo particles, with the 50:50 formulation showing the greatest thickness. Conversely, board strength decreased as bamboo particle concentration increased due to weak interfacial adhesion. Notably, panels made from treated rPP exhibited superior mechanical properties compared to those from untreated rPP, achieving a modulus of rupture (MOR) of 36.259 MPa and a modulus of elasticity (MOE) of 2048.215 MPa. These findings underscore the potential of utilizing nonwoven PP from disposable medical face masks, reinforced with bamboo fibre particles, to create eco-composite materials with enhanced sustainability and mechanical properties.

Fire resistance time prediction and optimization of cold-formed steel walls based on machine learning

Many full-scale experiments and numerical studies have been conducted to determine the fire performance of cold-formed steel (CFS) walls, but these studies are expensive and time consuming. This study proposes a machine learning (ML) based framework aiming at accurately predicting the fire resistance time (FRT) and optimizing the design of CFS walls under ISO 834 fire condition. To overcome the limitation of 32 experimental data points in the literature, a validated numerical method was used to generate 592 data points to expand the dataset of CFS walls, considering different wall configurations, various sheathing board types and thicknesses. The XGBoost (eXtreme Gradient Boosting) model was trained with numerical data and tested with experimental data. The hyperparameter tuning of the XGBoost model was implemented with Bayesian optimization, and it was found that the XGBoost model accurately predicted the FRT of CFS walls, with R2 and MAPE values being 0.933 and 8.46 %, respectively. The prediction process of the XGBoost model was interpreted by the SHAP (SHapley Additive exPlanations) method to determine the relative importance of input variables. The NSGA-II algorithm was adopted to optimize the FRT-cost dual-objective of CFS walls and the Pareto front including optimal solutions was emerging. The cost for each solution of Pareto front sets was lower than that in the real dataset at same FRT level. This phenomenon implied that the ML-based optimization framework successfully identified the cost-efficient design process. The proposed ML-based optimization framework offers a promising alternative for engineers to design CFS walls effectively with both mechanical and economic objectives.

Dewatering behavior of wet oil palm sawn timber during flat compression

ABSTRACT One obstacle to the industrial processing of oil palm wood is its nearly water-saturated state in green condition and its high tendency to develop cell collapse during kiln drying. This study analyzed mechanical dewatering by flat compression as an alternative pre-drying method for wet oil palm sawn timber. In the process, boards 700 mm long were compressed at ratios of 40% and 60% using a laboratory press, which resulted in water extraction of the free water varying between 38–52% and 60–73%, respectively. Since unperforated press plates were used, the water could only escape over the crosscut and long edges. The extent to which the crosscut and long edges were involved in dewatering was examined, and found to depend on the position of the board in the trunk due to the different water permeability conditions at the different heights. Permeability measurements, therefore, were carried out on cylindrical specimens using a specifically designed testing device. For the analysis of the hydrostatic pressure development in the boards, three pressure transducers were installed at different distances to the crosscut at half board thickness. The analysis of the recovery of compression showed, that the boards recovered to a large extend immediately after compression.

Deciphering Double-Walled Corrugated Board Geometry Using Image Analysis and Genetic Algorithms.

Corrugated board, widely used in the packing industry, is a recyclable and durable material. Its strength and cushioning, influenced by geometry, environmental conditions like humidity and temperature, and paper quality, make it versatile. Double-walled (or five-ply) corrugated board, comprising two flutes and three liners, enhances these properties. This study introduces a novel approach to analyze five-layered corrugated board, extending a previously published algorithm for single-walled boards. Our method focuses on measuring the layer and overall board thickness, flute height, and center lines of each layer. Through the integration of image processing and genetic algorithms, the research successfully developed an algorithm for precise geometric feature identification of double-walled boards. Images were recorded using a special device with a sophisticated camera and image sensor for detailed corrugated board cross-sections. Demonstrating high accuracy, the method only faced limitations with very deformed or damaged samples. This research contributes significantly to quality control in the packaging industry and paves the way for further automated material analysis using advanced machine learning and image sensors. It emphasizes the importance of sample quality and suggests areas for algorithm refinement in order to enhance robustness and accuracy.

A NUMERICAL INVESTIGATION ON FIRE PERFORMANCE OF INDUSTRIAL STEEL WAREHOUSES PROTECTED WITH GYPSUM‐BASED BOARDS

AbstractThis paper studies the fire performance of steel warehouse with their main elements insulated with fire protection boards composed of gypsum‐based mortars with perlite using the heat transfer and thermomechanical analysis in finite element (FE) software. The primary aim is to identify the optimal thickness of the fire protections boards based on the assigned fire model in thermal analysis. Besides that, a parametric study is also conducted by considering various factors that are often overlooked or not explicitly mentioned in fire design guidelines, such as EN 1991‐1‐2. The findings facilitate the development of optimized fire design approaches, ensuring the structural integrity and safety of steel warehouses under fire conditions.

Computational Analysis for the Evaluation of Fire Resistance in Constructive Wooden Elements with Protection

Wood is a material whose properties vary depending on different conditions, being particularly vulnerable to changes induced by high temperatures. When exposed to a fire situation, the wood properties suffer degradation, causing a char layer formation. Despite ensuring the protection of the inner core of the wood, the char layer reduces its resistant section. The evaluation of wood behavior under fire conditions is possible through experimental tests, simplified analytical models, and numerical models. To overcome difficulties in the development of experimental tests and in the approximations made to analytical methods, numerical models allow the evaluation of the fire resistance in a parametric way. First, this study will present a numerical model validated with an experimental test, using the finite element method. The validation of the results is based on the evolution of the temperature field, the char layer formation on the wooden elements, and its residual section, as well as the application of the thermal insulation criterion. The second part of the study evaluates the influence of geometric parameters, associated with different wooden constructive models with gypsum board exposed to fire. Different numerical tests are presented to evaluate the thermal and transient analysis of different wooden constructive elements with gypsum board. This type of constructive element presents cavities, making the numerical analysis in the study complex when approaching real models. The methodology applied allowed us to conclude that, at the same time, a smaller distance between wooden centers, a greater dimension of the wooden beam in height and width, as well as a greater thickness of gypsum board guarantee a better performance of the constructive wooden model.

Cyclable Variable Path Length Multilevel Structures for Lossless Ion Manipulations (SLIM) Platform for Enhanced Ion Mobility Separations.

Ion mobility-mass spectrometry (IMS-MS) is used to analyze complex samples and provide structural information on unknown compounds. As the complexity of samples increases, there is a need to improve the resolution of IMS-MS instruments to increase the rate of molecular identification. This work evaluated a cyclable and variable path length (and hence resolving power) multilevel Structures for Lossless Ion Manipulations (SLIM) platform to achieve a higher resolving power than what was previously possible. This new multilevel SLIM platform has eight separation levels connected by ion escalators, yielding a total path length of ∼88 m (∼11 m per level). Our new multilevel SLIM can also be operated in an "ion cycling" mode by utilizing a set of return ion escalators that transport ions from the eighth level back to the first, allowing even extendable path lengths (and higher IMS resolution). The platform has been improved to enhance ion transmission and IMS separation quality by reducing the spacing between SLIM boards. The board thickness was reduced to minimize the ions' escalator residence time. Compared to the previous generation, the new multilevel SLIM demonstrated better transmission for a set of phosphazene ions, especially for the low-mobility ions. For example, the transmission of m/z 2834 ions was improved by a factor of ∼3 in the new multilevel SLIM. The new multilevel SLIM achieved 49% better resolving powers for GRGDS1+ ions in 4 levels than our previous 4-level SLIM. The collision cross-section-based resolving power of the SLIM platform was tested using a pair of reverse sequence peptides (SDGRG1+, GRGDS1+). We achieved 1100 resolving power using 88 m of path length (i.e., 8 levels) and 1400 following an additional pass through the eight levels. Further evaluation of the multilevel SLIM demonstrated enhanced separation for positively and negatively charged brain total lipid extract samples. The new multilevel SLIM enables a tunable high resolving power for a wide range of ion mobilities and improved transmission for low-mobility ions.

Optimization Analysis of an Energy-Saving Renovation Scheme for Building Envelopes of Existing Rural Houses Based on a Comprehensive Benefit Evaluation

In the cold regions of China, the existing rural houses are widely distributed and in large numbers. There are widespread problems such as low thermal performance of building envelopes, high building energy consumption, and poor indoor thermal environments. Reducing the energy consumption of building heating by reforming the envelope structure can reduce the environmental pollution caused by heating. In this paper, the existing rural houses in Tongchuan City, Shaanxi Province are taken as the research object, and EnergyPlus software is used to calculate building heating energy consumption, and the schemes are compared and selected via the entropy value method. Based on a comprehensive benefit evaluation, the best scheme for the renovation of building envelopes of rural houses in Tongchuan City is put forward. The research results show that the energy saving rate of buildings can reach more than 50% after renovation. In the evaluation of energy saving, incremental cost, return on investment, carbon emission reduction and unguaranteed hours, the weights are 0.1915, 0.2104, 0.2312, 1755, and 0.187, respectively. The best renovation scheme for rural housing is as follows: the thickness of the XPS board is 90 mm for exterior wall insulation; the thickness of the XPS board is 80 mm for roof insulation; the window-to-wall ratio of additional sunspace is 0.6; and the type of exterior windows is a broken-bridge hollow aluminum window of 6 + 12A + 6 (mm).

Green Residential Building Design Scheme Optimization Based on the Orthogonal Experiment EWM-TOPSIS

A multi-objective decision method is proposed based on the combining orthogonal test, entropy weight method (EWM) with TOPSIS (technique for order preference by similarity to an ideal solution) in this article. The method is more objective and efficient than traditional methods in the design of green residential buildings. A villa in Nanjing was taken as an example, and the cost, building energy consumption, and daylight factors were used as decision-making indexes. A total of six control factors were selected: terrain elevation, window area, building orientation, the opening ratio of exterior windows, roof structure, and window glass material. Each factor was designed with three levels. First, a design scheme index system was constructed, and the orthogonal experimental design was used to select representative design schemes. Then, the EWM and the TOPSIS method were used to determine the weight of each index, a comprehensive evaluation of the residential building design scheme was conducted, and, finally, the optimal scheme was confirmed via range analysis. The results show that the multi-objective decision-making model based on the orthogonal experiment EWM-TOPSIS is suitable for green residential building design and the optimal solution obtained is “15 m elevation, a 1200 × 1500 mm size vacuum glass, an orientation of 170° and an external window opening ratio 45% with a 40 mm thick expanded insulation board roof”.

Factors affecting the daytime cooling effect of cool materials: A case study combining experiment and simulation

Cool materials, with their high reflectivity, can significantly reduce the heat absorbed by buildings in summer and thus reduce energy consumption. The amount of solar radiation received by building surfaces varies with their orientation, so the effectiveness of cool materials on different building surfaces may vary. This study investigated the effects of using cool materials on scaled-down building models and full-scale real buildings through a combination of experiments and simulations, considering factors including building surfaces of different orientations, material properties, and weather conditions. Both experimental measurements and simulation studies showed that applying cool materials on roofs has the best cooling effect, reducing indoor temperatures by 0.93 °C in full-scale models. The south and west façades also showed good cooling effects when using cool materials. The north façade has the least cooling effect when using cool materials. Compared to exposed cement boards and regular materials, cool materials showed significantly better cooling effects, similar to those of 2 cm thick XPS insulation boards. Overall, buildings with poorer thermal insulation performance benefit more from the cooling effect of cool materials in summer. Additionally, the cooling effect of cool materials is ineffective on cloudy and rainy days. We found that the cooling effect of cool materials was significantly reduced when the solar radiation was less than 400 W/m2. The findings of this study provide guidance for the use of cool materials in energy retrofitting of existing buildings and the construction of low-carbon cities.

Kiln-drying effectiveness as influenced by moisture content and density variation within a Scots pine timber batch

ABSTRACT Sorting of sawn timber batches is crucial for efficient kiln-drying. This study aimed to verify the hypothesis of different drying attributes of 25 mm thick sapwood and mixed Scots pine boards sawn from a group of butt, second, and top logs and assess the effects of kiln-drying. Three options dry-bulb temperature were taken into account. The drying results were evaluated based on the final moisture content distribution, changes in the cross-sectional dimensions of the sawn timber, drying time, and unit heat consumption. Correlations between sawn timber features, drying temperature, and drying results were analyzed using non-parametric statistical tests. The study proved the dependence of the initial moisture content and wood density variation of Scots pine sawn timber on the log type and the position on the round timber cross-section. The variation of drying attributes of the sapwood and mixed 25 mm Scots boards is insignificant in the final moisture content distribution and cross-sectional dimensions. However, green sorting may have only a beneficial effect on drying time and heat consumption.

Optimal Design of Thermal Cycling Reliability for Plastic Ball Grid Array Assembly Via Finite Element Method and Taguchi Method

Abstract A finite element simulation analysis model was developed for a plastic ball grid array (PBGA) assembly to analyze its behavior under thermal cyclic loading conditions. The stress distribution in the SAC305 solder joints at different locations within the array was investigated by using ANAND constitutive equations. Subsequently, the thermal fatigue life of the key solder joints was quantified. The study also examined the influence of the solder joint diameter, substrate thickness, solder joint height, printed circuit board (PCB) thickness, and mold compound height on solder joint stress. Optimization of assembly parameters was achieved through the application of the Taguchi method. An extensive analysis was conducted using different assembly parameter combinations, employing the L9(34) orthogonal array design to explore the thermal cycling effects. The computed average Von Mises stress Δσ for the critical thin-layer elements of solder joints located in hazardous positions within the assembly was notably affected by variations in the solder joint height, substrate thickness, solder joint diameter, and mold compound height. This impact ranked in descending order of significance as solder joint height, substrate thickness, solder joint diameter, and mold compound height. The optimal parameter combination determined was a solder joint height of 0.70 mm, a solder joint diameter of 0.85 mm, a substrate thickness of 0.51 mm, and a mold compound height of 1.12 mm. Implementing this optimized configuration led to a significant 4.07% reduction in average stress Δσ for the critical thin-layer elements within hazardous solder joints. Moreover, the extension of the thermal fatigue life was notably improved, achieving an impressive 51.72% increase.

Micromechanical Characterization of Continuous Fiber Date Palm Composites

ABSTRACT Date palm fiber composites with aligned, continuous fibers and epoxy matrix were prepared and mechanically characterized using micromechanical models. A hydrothermal process with microwave heating was utilized to extract the date palm frond (midrib) fibers, making the process eco-friendly as opposed to the commonly reported chemical extraction method. Single fibers were then characterized and found to have an average elastic modulus and ultimate tensile strength of 17.1 ± 1.5 GPa and 333 ± 27.4 MPa, respectively. Interfacial shear strengths ranging between 6 and 12 MPa were determined using a single-fiber pull-out test. Fibers were aligned to make uniaxial tensile samples with volume fraction ranging from 11% to 56%, elastic modulus ranging from 1.72 GPa to 9.52 GPa and ultimate tensile strengths ranging from 16.9 MPa to 43.8 MPa. All the results were found to obey “Rule of Mixtures” theory. The composite’s mechanical properties are similar to or exceeding those of the commercially available wood products such as medium density fiberboard, oriented strand board, thick particle board, hard fiber board, and plywood, making the hydrothermal approach with microwave heating as a promising approach for preparation of date palm composites and further opens up similar process pathway for other natural fibers.