Floor Panels Research Articles

Examination of the effect of air gaps on impact sound insulation performance of dry-type double floor system

The dry-type double floor system is a floor finishing structure widely installed for apartments and offices in Japan. However, after installing the double floor system, it is found that the impact sound insulation performance using a heavy-weight impact source is usually reduced due to the resonance of the air layer between the floor panels and the concrete slab. To reduce this adverse effect, small air gaps are set between the floor panels and the surrounding walls. In this paper, an experimental study is conducted firstly. A small specimen including particle board, support legs and air gaps is made to examine the effect of air gaps experimentally. Then, the air gaps are built as a Maxwell model considering that the air gaps act as the orifice of air spring. The theoretical analysis is conducted to explain the mechanism of impact sound insulation of the double floor system with or without air gaps. Finally, a parametric study is conducted to investigate the effect of air gaps with different dimensions on the impact sound insulation performance of the double floor system.

LCV Vehicle in-cab noise prediction and reduction using SEA based simulation approach

With increase in consumer demand vehicle OEMs are developing quieter vehicles at a design stage using acoustic simulation tools to reduce development cycle times avoiding costly proto builds and test iterations. Present work describes application of statistical energy analysis (SEA) simulation approach for in cab noise prediction and noise reduction through sound package optimization for LCV vehicle. In first step complete vehicle in-cab SEA model is prepared with baseline sound package concept. It consists of comprehensive definition of structural panels, interior and exterior cavities. Noise control treatment is modelled as multi-layer poro-elastic materials. Airborne noise excitations for sources engine, transmission, intake and exhaust muffler are applied. Source strengths for above sources were derived from dyno-coupled powertrain noise tests in the anechoic chamber. Load case of rated speed was considered neglecting tire and wind noise during simulation. Contribution analysis was carried out to find out sensitivity of different panels on interior noise at various frequencies. It was observed that bottom middle floor panel and rear glass panel were major noise contributors. Noise mitigation was carried out by optimizing floor panel sound package and intake air filter within given space constraints. These modifications resulted in overall 2 dB in-cab noise reduction

Weight minimization of train floors with acoustic and structural constraints

For high-speed trains, high noise levels are generated in the bogie from wheel-rail contact and aero-acoustic sources. Manufacturers try to minimize the floor transmission to the interior, e.g. by applying damping layers or by other measures. For vehicle noise control measures, the goal is often to achieve the sound reduction needed at lowest possible mass. Here, an optimization scheme is applied to minimize the mass of an extruded floor panel. Constraints are defined by limiting the maximum local floor deflection from passenger loads according to EN 12663-1 and the A-weighted interior sound level. Recognizing the periodic nature of the floor structure, a Finite Element model of a single periodic cell is set up, using periodic boundary conditions and the floor sound reduction is determined using a Statistical Energy Analysis approach. An analytic beam model is applied to determine the floor deflection from the passenger load. Design solutions meeting the constraints with the smallest possible mass are sought. Starting with a floor structure with 23.3 kg/m2, a final design with 18.0 kg/m2 is reached. In addition, the transmitted sound through the floor is reduced by 8 dBA. Convergence from different starting points is verified.

Study on factors affecting slip resistance performance of floor panels

Abstract In order to improve the slip resistence performance of floor panels used in escalators and moving walkways, as well as ensure the safety, the paper analyzes the impact of different factors on the slip resistence performance of floor panels through experiments. The test results reveal that the surface treatment degree of floor panels, environmental temperature and humidity, and passengers’ footwear all exert varying degress of impact on the slip resistence performance.

Production-oriented approach for optimal mass-customisation of floor panel layouts in cross-laminated timber (CLT) buildings

PurposeThis study aims to develop a production-oriented approach for optimal mass-customisation of floor panel layouts in cross-laminated timber (CLT) buildings. The study enables meeting building clients’ unique floor plan requirements at an optimal cost and simultaneously enhances manufacturers’ profit by minimising material and manufacturing process waste.Design/methodology/approachThe present research uses a hybrid approach consisting of field data collection, mathematical modelling, development of a Genetic Algorithm (GA) and scenario analysis. Field data includes engineered timber production information, design data and building code requirements. The study adopts the Flexible Demand Assignment (FDA) technique to formulate a mathematical model for optimising the design of mass timber buildings and employs GA to identify optimal production solutions. Scenario analysis is performed to validate model outputs.FindingsThe proposed model successfully determines the load-bearing wall placement and building spans and specifications of floor panels that result in optimal production efficiency and the desired architectural layout. The results indicate that buildings made of a single category of thickness of panels but customised in various lengths to suit building layout are the most profitable scenario for CLT manufacturers and are a cost-effective option for clients.Originality/valueThe originality of the present study lies in its mathematical and model-driven approach towards implementing mass customisation in multi-storey buildings. The proposed model has been developed and validated based on a comprehensive set of real-world data and constraints.

Withdrawal Capacity of a Novel Rigging Device for Prefabricated Wood I-Joist Floor Panels

Prefabricated wood construction relies heavily on efficient material handling, yet rigging system design for floor panels remains understudied. This study introduces a novel rigging device that attaches to prefabricated wood I-joist floor panels using self-tapping screws, avoiding potential damage caused by predrilled holes in the sheathing panels and framing members. To establish allowable lifting capacities and optimal installation practices, comprehensive withdrawal tests were conducted on 114-floor panel specimens. Factors influencing withdrawal capacity, such as anchor plate placements, flange materials and width, screw type and quantity, and sheathing panel thickness, were systematically evaluated. Results indicate that withdrawal capacity does not scale linearly with screw quantity and that anchor plates with eight screws centered on the flange enhance performance by up to 20% compared to four-screw configurations. Unexpectedly, thinner sheathing panels yielded higher capacities, potentially due to increased screw penetration depth in the joist flange. In addition, anchor plate orientation, flange width, and flange materials also impact capacity. These findings provide essential data for designing reliable and efficient rigging systems in prefabricated wood construction.

Decentralised [formula omitted] robust control of MTMDs for mitigating vibration of a slender MDOF floor configuration

In this research, a novel robust decentralised H (H∞ and H2) design combined with a pattern search method (PSM), incorporating considerations of multiple modal dynamics, was developed to address the vibration issue in slender structures. To verify the effectiveness of the concept, a full-scale laboratory reconfigurable multiple degrees of freedom (MDOF) test-bed floor panel structure was selected, equipping with a passive multiple-tuned mass damper (MTMD) as a coupling system. The optimal parameters of the MTMDs were tailored using the decentralised H design and the PSM, considering the dynamic engagement of multiple modes. Furthermore, a crucifix-type configuration of 2DOF MTMDs was proposed to mitigate the vibration of the floor panel structure. Full-scale forced vibration testing (FVT) was conducted to validate the dynamic performance of the 2DOF MTMDs. The test results provide satisfactory verification and high-quality curve-fitting testing data for parameter study and dynamic simulation. By examining the field data from the 2DOF MTMDs and performing various numerical simulations and analyses, the control performance robustness of the MTMDs was comprehensively evaluated, considering practical engineering variations such as the number and stiffness of MTMDs, as well as the stiffness and mass of the floor panel structure. As a result, the proposed H control strategies for the MTMDs demonstrated robust control capabilities by effectively dissipating significant amounts of externally applied energy.

EXPERIMENTAL DETERMINATION OF FLOOR PANELS DEFORMABILITY OF A LARGE-PANEL SYSTEM BUILDING AFTER RENOVATION

This paper deals with a field tests of prefabricated reinforced concrete floor panels of a multistory building by the method of hydrostatic loading. Object of study is presented by 3 damaged floor slabs of a 9-storey residential building which was hit during the russian invasion. After renovation of panels using the constructive solution which consists of a reinforced build-up layer in the compressed zone (upper part) and additional external reinforcement in the stretched zone (lower part) connected to each other with the help of anchor connections, a series of tests with water loading were set. For creation of loading an inventory pool was used, which was gradually filled with water at a step of 1kN/m2. Maximum created loading level was 5kN/m2 which corresponds to the operational load. After reaching the maximum load, the panels were left under load for 15 hours and then fully unloaded in steps of 1kN/m2. For each panel two type of tests were established: first when panel had both upper and lower part of reinforcement, and second – when lower reinforcement within steel beams was removed. The idea of dismantling of steel beams connected with previously performed numerical analysis which gave to little difference in deflections of panels for these two cases. Deflection measurements at critical locations along with thorough visual inspection were conducted during the loading and unloading cycles. No damage was observed during the in-situ loading and unloading cycles. Maximum vertical deflection for panel before dismantling of beams lies in the diapason of 1.95-2.1mm and 2.31-2.4mm after they were removed. These results meet the requirements of regulatory restrictions on the maximum deflection equal to 20 mm for this structure. Difference in deflection for two cases doesn’t exceed 20% which allows to abandon the use of lower reinforcement in the form of steel beams in the future. As the size of the pool doesn’t cover the whole panel area, the equivalent uniformly distributed load was also calculated using Lira software. Keywords. Large panel system house, reinforcement, floor panel, method of hydrostatic loading, deflection.

Environmentally Sustainable Raised Access Flooring Product Development

Raised access floors are nowadays widely used in buildings. A novel raised access flooring product is developed by this research, with a set of sustainable features, including less environmental impact and high strength. Its floor panels are made of polyurethane (PU) reinforced with glass fibre, which is light-weight and fire-resistant, replacing the traditional floor panel materials, and the panels are supported by simplified steel stringers to reinforce the strength of the flooring product. Instead of the conventional sandwich design consisting of a core material encapsulated by outer layers, the new floor panel design adopts the reinforced PU as its sole material, which not only simplifies the structure but also reduces floor weight and costs. The sustainable advantage is further approved by the environmental life cycle assessments of the new raised flooring product in comparison to traditional ones made of cement and woodchips, with results showing that the new floor product’s total environmental impact is 52% less than cement floor and 47% less than woodchip board floor. Further, the finite element analysis (FEA) was carried out, and the experimental test was conducted to verify the FEA results, indicating that the new product’s strength is higher than the requirements of the raised access flooring product standards. There is no raised access flooring product made of PU reinforced with glass fibre available in the market, and, hence, the new product developed by this research is a novel contribution.

Reliability framework for CLT floors in out-of-plane bending using Monte Carlo simulation

Sustainably sourced engineered wood products (EWP) such as cross-laminated timber (CLT) floor panels are viable alternatives to conventional concrete and steel, however their inherent natural variability increases perceived risks and limits wide-spread adoption. The reliability index (β) is the metric used by design standards to communicate allowable structural risk. Although not included directly in any structural capacity equations, it governs all the partial resistance factors and load amplification factors that inform those design code calculations. CLT floors have significant partial resistance factors due to the natural variability of the material that effectively penalise the calculated design strength of those products. By exploring their reliability there is the potential to allow these products to be designed more efficiently, leading to increased competitiveness among traditional materials and less waste. A novel statistical capacity prediction model that goes beyond a simple averaged-value strength assumption to include consideration of the variability between individual boards within a panel was validated against experimental data. A CLT database of 237 out-of-plane bending test results was collected for the first time to inform an appropriate model error factor. Monte Carlo simulation (MCS) approaches were adopted to predict the reliability levels of CLT panels by defining the material, geometrical and loading parameters as random variables and assigning each a mean, coefficient of variation and appropriate distribution. The target and calculated reliability levels were compared across both Eurocode 5 and the North American codes ANSI/APA PRG 320 and CSA O86 as the preeminent CLT design codes internationally. This study found that the calculated reliability levels met or exceeded both codes in most scenarios. The impacts of width, load ratio, material strength distribution, and CLT layups on the expected failure probabilities were explored with sensitivity analyses. The MCS framework was also applied to the calibration of an appropriate resistance factor for CLT design to inform the potential creation of an Australian CLT design code. A resistance factor of 0.85 was calibrated which falls between the equivalent European and North American code resistance factors.

Multi-objective optimization of composite sandwich structures using Artificial Neural Networks and Genetic Algorithm

Sandwich structures offer significant opportunities to improve the performance of many industrial applications such as aerospace, automotive, and marine. The design of a composite sandwich structure is often challenging because it is driven by the balance between the weight and cost of these structures. In this paper, a multi-objective optimization model using a Genetic Algorithm (GA) and an Artificial Neural Network (ANN) is presented to evaluate a new optimization approach in terms of weight and cost minimization for the composite sandwich structures. Classical lamination and beam bending theories were used, along with Monte Carlo simulation, to generate the design data for the proposed composite sandwich structure, which is applied as a floor panel for a high-speed train. Multilayer feedforward neural networks were used for predicting safety factors, cost, and weight of the designed structure based on the following inputs: core density, core thickness, face sheet materials’ combinations, and applied load. The trained Neural Network model was able to predict the considered results with a good performance metric, namely the coefficient of determination (R2 = 0.99) and the Mean Square Error (MSE = 1.3·10−5).Multi-objective optimization for cost and weight minimization was performed with a Genetic Algorithm using the derived ANN model. The obtained Pareto front provided several non-dominated optimal points leading to insights on the optimization process. The Finite Element Method (FEM) was used to model the key points of the optimal designs (i.e. the design with the lowest cost, weight, and Pareto optimal points). The FEM and optimization results had a maximum deviation of about 8.9%, indicating a good agreement between the two techniques.The newly elaborated methodology demonstrates a new approach for obtaining the optimum design of the investigated composite sandwich structure constructed from honeycomb core and laminated face sheets in terms the cost and weight. The study concluded that the use of Carbon Fiber-Reinforced Plastic (CFRP) or Fiber-Metal Laminate (FML) face sheets results in significant weight savings of about 59.5% and 48.6%, respectively, compared to an all-aluminum sandwich structure.

Evaluation of vibration properties of an 18-story mass timber–concrete hybrid building by on-site vibration tests

Timber–concrete hybrid structural systems are a practical option to provide tall mass timber buildings with a lateral load-resisting system. This paper discusses the dynamic behavior of an 18-story timber–concrete hybrid building based on the vibration properties evaluated by on-site vibration tests. First, microtremor measurements and human-powered excitation tests were carried out and the obtained vibration data were analyzed using a stochastic subspace identification method to derive natural frequencies, damping ratios, and mode shapes. Then, a finite-element (FE) model was developed based on detailed structural design information, and its eigenvalues and eigenvectors were compared with the test results. The vibration test results showed various mode shapes, including in-plane deformation of the floor diaphragm composed of cross-laminated timber (CLT) panels. The damping ratios in all the modes were scattered between 1 and 3%, and no frequency dependency was observed. The modal properties of the FE model agreed well with the test results by considering the additional stiffness of non-structural components. In order to simulate the in-plane deformation of the CLT floor diaphragm, detailed modeling of the connection between each CLT floor panel and the connection between CLT floor panels and concrete cores is recommended. The findings provide practitioners with an insight into dynamic properties and FE modeling methods of tall timber–concrete hybrid buildings.

Hookahs and smoldering hookah coals as an object of forensic fire and technical expertise

The subject of the study is to establish the involvement of smoldering hookah coals in the occurrence of a fire during the production of a forensic fire-technical examination. Currently, there is no universal concretized algorithm for determining the involvement of tobacco smoking devices and hookah coals in the occurrence of a fire for all possible cases of fire. The authors have attempted to combine well-known information about the detection of signs of exposure to combustible materials from a relatively low-power ignition source with the results of experiments and studies of smoldering hookah coals. Two types of hookah coals were selected as objects of research: cubic natural charcoal for hookah, fast-burning cylindrical coal. Cotton fabric, cotton wool, paper, wood (pine), synthetic carpet with fine pile, synthetic carpet with large pile, soft decorative elements with synthetic filling and a pillowcase made of furniture fabric, PVC floor materials (linoleum, PVC tiles), floor panels, lined with polymer films (laminate). In conducting this study, a systematic approach was applied to the analysis of the situation of a fire-related incident, as well as general scientific empirical and theoretical research methods (observation, comparison, description, measurement, analysis and synthesis, etc.) The results of empirical studies confirm the hypothesis of the formation of deep charring zones in places of contact of hookah charcoal with combustible materials (wood, laminated floor coverings). Based on the results of experimental studies, a step-by-step algorithm for constructing versions about the occurrence of a fire from smoldering hookah charcoal is formulated, including focusing the attention of an expert (a person conducting an inspection of the scene of an incident related to a fire) on the need to take into account factors such as the time of the fire and the induction period of ignition, the presence of conditions for heat accumulation, the presence of air exchange, the presence of an air inflow into the smoldering zone, the presence of signs of the dynamics of fire propagation, characteristic of low-power ignition sources. It is noted that the probability of burning from smoldering hookah coal increases in cases where conditions are created for the smoldering process to proceed with minimal heat loss, the possibility of heat accumulation and the presence of an oxidizer (oxygen in the air) in sufficient quantities.

Localization of solar panel cleaning robot combining vision processing and extended Kalman filter.

In this study, we introduce a method for estimating the position of a self-driving solar panel-cleaning mobile robot. This estimation relies on line counts, typically 16 cm in panel width, obtained through image processing on the panel floor, along with wheel encoder information and inertial sensor data. To achieve accurate line counts, we introduce two adjusted threshold values and allow offsets in these values based on the robot's speed. Additionally, inertial measurement unit (IMU) signals assist in determining whether a line is horizontal or vertical, depending on the robot's movement direction on the panel, utilizing the robot's heading angle and detected line angle. When the robot is positioned between lines on the panel, more precise location estimation is necessary beyond simple line counts. To tackle this challenge, we integrate the extended Kalman filter with IMU data and encoder information, significantly enhancing position estimation. This integration achieves an RMSE accuracy value of up to 0.089 m, notably at a relatively high speed of 100 mm/s. This margin of error is almost half that of the vision-based line-counting method.

Effect of wooden floorboards on the vibration of timber floor

This study is aimed at investigating those parameters related to timber flooring that can affect the acceptability of vibration behaviour of a timber floor in a residential building in view of the criteria stated in Eurocode EC5. The timber floor investigated is made of OSB/3 floorboards and timber joists. The parameters that are investigated in this study are thickness of flooring, floor joist span, joist spacing and connection of floorboards to the joists. In this context, two cases are considered. First: the flooring is nailed or screwed to the joists and no composite action or interaction is obtained between joists and floorboards. Second: the flooring is glued sufficiently to the joists and full interaction is obtained. The result suggests that glued floorboards perform much better with respect to natural frequency, static deflection and peak floor velocity than nailed or screwed floorboards. In almost all cases of glued floorboards, the result complies fully with the Eurocode 5 design vibration requirements. However, as floor lengths increase, the static deflection will increase beyond the allowable limit, especially for relatively thin floor panels and relatively widely spread joists. For both cases, increasing floorboards thickness and decreasing the joist span by adding more beams can yield even better results to satisfy the requirement of vibration comfort.

Methodological approaches to designing biophilic rehabilitation buildings

The article aims to analyse current architectural and engineering research and developments in the treatment of post-traumatic disorders. The study thoroughly explores the aspects which are the basis of the development of rehabilitation buildings. It deals with a comprehensive series of theoretical and experimental studies aimed at devising and validating innovative, inclusive, trauma-informed architectural and landscape solutions, as well as eco-oriented, resource-efficient structural solutions. The article delineates the fundamental principles of spatial organization grounded in the concept of biophilic design. The study developed a conceptual design solution for a rehabilitation building with elements of biophilic design, as well as designed modular elements such as wall panels, floor panels, and roofing panels, which proved to be effective. To substantiate the proposed functional-planning and architectural-engineering solutions, a spatial model of the building has been constructed, and static calculations have been performed.

Out-of-plane characteristics of cross-laminated bamboo and timber beams under variable span three-point loading

Given the exceptional mechanical properties of cross-laminated bamboo and timber (CLBT) and its ability to efficiently utilize bamboo and timber resources, CLBT holds considerable potential for applications in modern sustainable timber and bamboo structures. CLBT panels, when used as floors or roofs, typically experience out-of-plane loads. This study investigates the out-of-plane bending and shear characteristics of 5-layer CLBT and cross-laminated timber (CLT) specimens using the variable span three-point loading test method. The results indicated that the developed CLBT exhibited superior mechanical properties compared to CLT, offering a preliminary demonstration of its value in engineering applications. In addition, factors such as the span and outermost lamination influenced the failure modes, vertical deflections, strain distributions, ductility indices, and energy absorption characteristics of CLBT and CLT specimens. This study provides a foundational reference for using CLBT as floor and roof panels subjected to out-of-plane loads and lays the foundation for further research.

Quantifying the effect of end support restraints on vibration serviceability of mass timber floor systems: Testing

Design of mass timber floor systems is commonly governed by vibration serviceability due to high stiffness-to-weight ratio and low inherent damping of timber. Research and design practice have shown that static deflection under a concentrated load and fundamental natural frequency can be effective and robust indicators for vibration performance of mass timber floors. These design parameters are normally calculated by assuming simply supported conditions in existing design methods. However, such an assumption deviates from actual floor supports, especially in platform-framed buildings, and in-situ end support restraints have been widely recognized as a significant factor affecting the vibration performance. The purpose of the study is to quantify the influence of end support restraints on vibration serviceability of mass timber floors in platform construction through a comprehensive experimental program and analytical treatment. This paper is the first part and focus specifically on the experimental work on cross-laminated timber (CLT) panels. In particular, extensive laboratory tests have been conducted on different CLT floor panels with various end support restraints induced by top loads, self-tapping screws and steel angle brackets. The fundamental natural frequency and mid-span deflection under a concentrated load were measured for each end support configuration. The rotational restraint stiffness was determined by comparing results of restrained supports to those of simple supports and represented as end fixity factors. The analysis of test results shows that the CLT floor-to-wall connection exhibited inherent non-linear behaviour and such characteristic was more significant for higher top loads. Compared with screws and brackets, the top loads dominated the partially restrained effect but such dominance gradually diminished for lower-level top loads. In addition, support wall thickness notably impacts the support restraint. It was then suggested that the clear span could be used to determine deflection and frequency in the design, but further investigation is needed.

Experimental and numerical study on transfer force characteristics and sound pressure in air layer of dry-type double floor system

The dry-type double floor system is a floor finishing structure that is mainly composed of floor panels and support legs, and widely installed for apartment buildings and offices in Japan. In this paper, an experimental study is conducted firstly. Several small specimens composed of ten support legs and floor panels are made, and the elastic properties of floor panels are determined by using the impact hammer in advance. In the experiment, two boundary conditions of the air layer are examined where the periphery of the specimen is fully open or closed by wooden frames. The transfer force of each support leg, the sound pressure of the air layer and the displacements of floor panels are measured while impacted by the standard rubber ball. Then, a numerical study is conducted by finite element analysis. The support legs and floor panels are built as Kelvin-Voigt model and plate element respectively. The vibro-acoustic analysis is conducted to investigate the influence of the air layers. It is shown that the gravity of floor panels and the contact condition of support legs on the concrete slab should be modelled to improve the accuracy of numerical analysis.

The effect of aluminum body on acoustic characteristics of vehicle

Automobile manufacturers have extensively researched on applying various lightweight materials to automobiles to match with the strict emission standards. In recent automotive industry, in terms of material, a main stream to reduce vehicle weight could be divided into aluminum and engineering plastic, respectively. When it comes to cost, reusability, aluminum materials have greater advantages than engineering plastics. In this study, the effect of the sound characteristics of the vehicle according to the body material was confirmed. Accelerator Position Sensor 100%, Constant speed (80kph), PBNR (Power Based Noise Reduction), Input Point Stiffness and Acoustic Sensitivity were tested under the condition that the same sound absorbing parts were applied to two vehicles made of steel and aluminum, each FRONT FLOOR, REAR FLOOR, LUGGAGE FLOOR, and ROOF panels of the vehicle body. As a result of test data comparison between steel and aluminum bodies, the study shows pros and cons of respective materials.