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Jakościowe aspekty w konstrukcjach meblowych. Poprawa jakości poprzez użycie różnych materiałów konstrukcyjnych
Withdrawal Resistance of T-Nuts in Various Furniture Materials
T-nuts are factory installed in the holes of the ready-to-assemble furniture components. There is a risk that the t-nut spontaneously falls out during transport or storage and get lost; the t-nut can also be pushed into inaccessible spaces during assembly. These complications can make furniture assembly impossible. For this reason, sufficient force to hold the t-nut in the hole is essential. The article presents the test results of the forces holding the t-nuts in five furniture materials (softwood, Oriented Strand Board, plywood, and particleboard in two variants). The M6 t-nuts with four prongs were installed in predrilled 8 mm holes. The resistance to withdrawal of the t-nuts was measured with a universal testing machine. The tested materials could be divided into three groups in terms of the risk of the t-nut falling out: softwood and plywood – low risk, F = 1113.2-1158.0 N; OSB and particleboard – moderate risk, F = 592.3-645.5 N, particleboard with a pad – high risk, F = 645.5 N. The results show that the withdrawal resistance is not correlated with the density of the wood material, and that it decreased with the degree of wood material processing – the less processed the material, the greater the resistance to withdrawal of the t-nuts.
Modelling Upholstered Furniture Frames Using the Finite Element Method
This study employs the finite element method to propose a model-based design strategy for upholstered furniture frames. Three-dimensional discrete models of these frames were created, considering the orthotropic characteristics of pine (Pinus sylvestris L.) and spruce (Picea abies L.) wood, reinforced structurally with glue joints and upholstery staples. The modelling process utilised the CAE system Autodesk Inventor Nastran, applying the finite element method (FEM). Static analyses were performed by simulating standard loading conditions. The calculations incorporated the stiffness coefficients of the frame’s comb joint connections. The findings illustrate the stress distribution, displacements, and equivalent strains within the furniture frame models. The deformation and strength parameters of the frames introduce a novel perspective on designing upholstered furniture structures using the component-based FEM approach. These outcomes are applicable to the development of upholstered furniture designs.
Improving the stiffness of the corner connections in wooden door frames
The research aimed to determine the strength and stiffness of corner joints in interior door frames, depending on their construction and the modifications made to the design of the door frame joints. Initially, two models were compared: model 1, with two connectors using a clamping screw at an angle of 45°, and model 0, with a single connector using a cam joint at an angle of 90°. In all tests, model 1 exhibited significantly better mechanical properties. To improve the performance of model 0, three alternative construction models (A, B, and C) were proposed by changing the position of the door frame mounting holes. In the compression test, model A showed an increased bending moment compared to model 0, while models B and C showed no such improvement. In the tension test, the bending moment values remained at a similar level across all construction variants, including model 0. In terms of bending moment, the best result in compression was achieved by model A (48.26 Nm), and in tension by model B (48.72 Nm). The highest stiffness was demonstrated by model 1 (up to 42.38 kNm/rad), while among the alternative models, model C showed the best result in tension (33.98 kNm/rad). Due to the favourable increase in bending moment under compression in model A and the insignificant changes under tension across all variants, model A is considered the optimal solution. To enhance the strength of the door frame, offset holes can be applied as proposed in this model.
Elements of Designing Upholstered Furniture Sandwich Frames Using Finite Element Method
This paper presents an approach to the design of an upholstered furniture frame using the finite element method and empirical studies. Three-dimensional discrete models of upholstered furniture frames were developed taking into account orthotropic properties of solid pine wood (Pinus sylvestris L.) without and with details strengthening their structure in the form of glue joints and upholstery staples. Using the CAE Autodesk Inventor Nastran finite element method, linear static analyses were performed by simulating normative loading. The finite element method was performed considering the experimentally determined stiffness coefficients of the PCAC adhesive and staple joints. As a result, stress, displacement, and equivalent strain distributions were obtained for upholstered furniture frame models with stapled corner joints. The deformation and strength behavior of the upholstered furniture frames was improved by reinforcing with a wood strip. A new approach to the design of upholstered furniture frame frames using the FEM method with stapled component connections was developed and tested. The results of the study can be applied in the optimization of upholstered furniture construction.
Energy Consumption for Furniture Joints during Drilling in Birch Plywood
The purpose of this study is to support eco-design ideas and sustainable manufacturing techniques by examining the energy consumption related to drilling holes for different furniture connections. The experimental model is a simple piece of furniture made from birch plywood with three different types of joints. Eccentric joints, confirmat screws, and dowel measurements of energy consumption with a CNC drilling and milling machine show different values for every kind of connector. The energy consumption was measured using a portable power quality analyzer, specifically the PQ-box 150 manufactured by A:Eberle GmbH & Co. KG Nürnberg, Germany. This device likely adheres to industry standards for energy measurement, ensuring accurate and reliable results. The measurement process involved recording energy consumption at different stages of the machining process, allowing for the analysis of specific cutting work and total energy consumption for various joint types. Dowels exhibit the lowest energy consumption at 0.105 Wh for one furniture joint, confirmat screws at 0.127 Wh, while eccentric joints, despite their higher energy consumption (0.173 Wh), offer enhanced transportability and assembly flexibility of a piece of furniture. Specific cutting power for one selected piece of furniture was 227.89 J/mm3 for dowels, 190.63 J/mm3 for eccentric joints and 261.68 J/mm3 for confirmat screws.
Impact of seat and back angle settings on seating furniture quality: an experimental study
Impact of Seat and Back Angle Settings on Seating Furniture Quality: An Experimental Study. The fundamental measure of the quality of seating furniture is seating comfort. Sitting comfort is described in the literature by the discomfort coefficient D, calculated from the pressure values and distribution measured between the human body and a sitting furniture "body support system". The work aims to experimentally verify the influence of selected anthropometric features on sitting comfort. The research was carried out on 12 people using a piezoelectric sensor mat and a model of adjustable sitting furniture. The study investigated how different seat and backrest inclination variants impact pressure distribution. The test results are the values of the contact pressures and discomfort coefficients D for nine combinations of the backrest and seat inclination related to the anthropometric characteristics of the tested group of people. The results indicate that anthropometric factors, such as body mass index (BMI) and user gender, significantly impact objective seating comfort. These findingswill help optimize the seating furniture dimensions at their design stage
Screw Withdrawal Resistance from WPC Profiles Used in Door Frame Production
This study investigates the screw withdrawal resistance (SWR) of hollow wood–plastic composite (WPC) door frames, which serve as moisture-resistant alternatives to traditional wood-based materials. The tested WPC, characterised by a density of 1.33 g/cm3 and a polymer-bound lignocellulosic filler, exhibits superior dimensional stability and low water absorption—under 4% after 24 h of immersion. The research focuses on how the unique chambered geometry of these industrial profiles affects the anchoring of 20 mm conical wood screws used to mount essential fittings such as hinges and lock catches. The SWR was determined using a universal testing machine in accordance with the modified EN 320 standards. Results indicate that the installation location within the profile significantly dictates load-bearing capacity: the band profile (lock catch) achieved an average SWR of 525.65 N, while the beam profile (hinge) averaged only 275.25 N. This performance gap arises because screws anchor only into internal “ribs” rather than the full material depth. Since these values are considerably lower than those of traditional particleboard (~1364–1775 N), the study highlights a critical need to optimise screw dimensions to ensure the structural stability and safety of hollow WPC door systems.