Panel Structure Research Articles

A Novel Design of a Pre-separation Panel Structure to Protect Against the Impact of an Explosion in an Aircraft Plenum Chamber

A Novel Design of a Pre-separation Panel Structure to Protect Against the Impact of an Explosion in an Aircraft Plenum Chamber

Correction to: Feasibility of computational intelligent techniques for the estimation of spring constant at joint of structural glass plates: a dome-shaped glass panel structure

Correction to: Feasibility of computational intelligent techniques for the estimation of spring constant at joint of structural glass plates: a dome-shaped glass panel structure

Coarse Integral Volumetric Imaging Display with Time and Polarization Multiplexing

This paper introduces an innovative approach to integral volumetric imaging employing time and polarization multiplexing techniques to present volumetric three-dimensional images. Traditional integral volumetric imaging systems with a coarse lens array often face moiré pattern issues stemming from layered panel structures. In response, our proposed system utilizes a combination of time and polarization multiplexing to achieve two focal planes using a single display panel.

Benefit of structural access panels (SAP) for post-earthquake structural health monitoring

Benefit of structural access panels (SAP) for post-earthquake structural health monitoring

Panel Paintings Inspection Analysis Using Active Thermography in the Mid-Wave and Long-Wave Infrared Region

Active thermography was used for characterisation of multi-layered paintings panel structures and analysis of defects caused by aging and environmental effects. Pulsed Thermography setup was applied to provide and inspect a dynamic thermal response, which was recorded by mid- and long wavelength infrared TELOPS cameras. Control, synchronization and data analyses were provided by Professional software (DisplayImg 7). Active thermography was demonstrated as being appropriate for characterization of various defects on painting layers and detection of under-drawings, pentimenti and canvas. Such multispectral approach provided simultaneous complementary information on the specimen under inspection.

ИННОВАЦИОННЫЕ УЗЛОВЫЕ СОЕДИНЕНИЯ КОНСТРУКЦИЙ ИЗ CLT

The article discusses innovative nodal joints of structures made of cross-laminated timber (CLT), since nodal joints and their design have a great influence on the properties of building struc-tures: their load-bearing capacity, stability, fire-resistant and acoustic properties. This article discusses options for connecting to a computer from CLT: 1) TITANIUM in the corners, tracking the speed of separation and shear; 2) SLOT connecting elements for structural panels; 3) SPIDER connection and widening system for racks and floors; 4) COLUMN connection system- overlap; 5) the combined X-ray radiation system, from the point of view of such characteristics as: insignificant connection, lack of settlement connection, complexity and speed of muntage and others, as well as places of residence separated from others and disadvantages obtained as a result of the association

Camptothecin structure simplification elaborated new imidazo[2,1-b]quinazoline derivative as a human topoisomerase I inhibitor with efficacy against bone cancer cells and colon adenocarcinoma

Camptothecin is a pentacyclic natural alkaloid that inhibits the hTop1 enzyme involved in DNA transcription and cancer cell growth. Camptothecin structure pitfalls prompted us to design new congeners using a structure simplification strategy to reduce the ring extension number from pentacyclic to tetracyclic while maintaining potential stacking of the new compounds with the DNA base pairs at the Top1-mediated cleavage complex and aqueous solubility, as well as minimizing compound-liver toxicity. The principal axis of this study was the verification of hTop1 inhibiting activity as a possible mechanism of action and the elaboration of new simplified inhibitors with improved pharmacodynamic and pharmacokinetic profiling using three structure panels (A-C) of (isoquinolinoimidazoquinazoline), (imidazoquinazoline), and (imidazoisoquinoline), respectively. DNA relaxation assay identified five compounds as hTop1 inhibitors belonging to the imidazoisoquinolines 3a,b, the imidazoquinazolines 12, and the isoquinolinoimidazoquinazolines 7a,b. In an MTT cytotoxicity assay against different cancer cell lines, compound 12 was the most potent against HOS bone cancer cells (IC50 = 1.47 μM). At the same time, the other inhibitors had no detectable activity against any cancer cell type. Compound (12) demonstrated great penetrating power in the HOS cancer cells' 3D-multicellular tumor spheroid model. Bioinformatics research of the hTop1 gene revealed that the TP53 cell proliferative gene is in the network of hTop1. The finding is confirmed empirically using the gene expression assay that proved the increase in p53 expression. The impact of structure simplification on compound 12 profile, characterized by the absence of acute oral liver toxicity when compared to Doxorubicin as a standard inhibitor, the lethal dose measured on Swiss Albino female mice and reported at LD50 = 250 mg/kg, and therapeutic significance in reducing colon adenocarcinoma tumor volume by 75.36 % after five weeks of treatment with compound 12. The molecular docking solutions of the active CPT-based derivative 12 and the inactive congener 14 into the active site of hTop1 and the activity cliffing of such MMP directed us to recommend the addition of HBD and HBA variables to compound 12 imidazoquinazoline core scaffold to enhance the potency via hydrogen bond formation with the major groove amino acids (Asp533, Lys532) as well as maintaining the hydrogen bond with the minor groove amino acid Arg364.

Advancing spacecraft demisability through a novel composite bolt joint system: a step toward sustainable and safe space environments

From the recent awareness of the booming number of space debris and their derived worldwide re-entry event threat originating from the use of high survivability components, complementary mitigation measures must be taken for future orbital elements. In this direction, the implementation of a design for demise at an early stage of spacecraft conception allows a progressive and effective solution. As part of a collaborative effort launched by École Polytechnique Fédérale de Lausanne and the European Space Agency, we focus on the evaluation of polymer composite bolts as the main structural satellite panel fastening systems to improve the overall spacecraft demisability during its destructive re-entry into the atmosphere as compared to baseline critical systems, while maintaining equivalent mission-relevant properties. Two carbon fiber-reinforced polyetheretherketone (PEEK) designs were compared to a stainless steel baseline in terms of static properties at room temperature, dynamic properties over a temperature range, as well as demise capability by static re-entry simulation testing. The results led us to identify a promising short CF/PEEK composite bolt design.

Экспериментальные исследования трехслойных стеновых панелей с наружными слоями из конструкционного бетона и средним слоем из бетона низкой теплопроводности

Three-layer wall panels with a thermal insulation layer made of low thermal conductivity concrete are an alternative solution to single-layer structures made of lightweight concrete and three-layer ones with a thermal insulation layer of effective insulation materials, such as polystyrene foam or mineral wool. For them, the basic principles of designing single-layer lightweight concrete panels are retained, including their reinforcement with spatial frames. These wall panels can be used as load-bearing walls of residential buildings, as well as self-supporting and curtain walls of public and industrial buildings. Tests of full-scale wall panel structures were carried out, which revealed and confirmed the reliability of the monolithic connection of layers between different concrete layers at various stages of the structure’s operation, up to destruction.

Individual credit market experience and beliefs about bank lending policy: evidence from a firm survey

AbstractUsing the Austrian Business Survey between 2011 and 2016, we study how firms' individual credit market experiences influence their beliefs about the bank lending policy. Firms that have recently experienced a loan rejection are more likely to believe that the lending policy is restrictive. We see similar effects for firms that were granted loans, but with conditions worse than anticipated. Exploiting the panel structure shows that firms without recent credit market experience are less likely to change their beliefs, which converge towards the middle category. Our findings are in line with theories of rational inattention and with asymmetric experience effects.

A new type of engineered wood product: Cross-laminated-thick veneers

The global scarcity of high-quality solid wood resources has propelled efforts towards developing high value-added products utilizing fast-growing wood. However, the inherent low quality of fast-growing wood poses a significant challenge for its use in engineered wood products. In response to this challenge, this study focuses on the transformation of larch logs into a novel engineering wood product termed cross-laminated-thick veneers (CLTV). The process involves rotary cutting larch logs into 7.5 mm thick veneers, followed by hygrothermal treatment to alleviate stress, and ultimately assembling layers of thick veneers oriented at right angles, securely bonded to form structural panels. The investigation into the mechanical properties of CLTV reveals promising results. The static bending strength and modulus of a 15-layer CLTV with a thickness of 105 mm exhibit noteworthy values of 62.29 MPa and 10986 MPa, respectively. These values stand in comparison to the performance metrics of cross-laminated-timber (CLT) with only 3 layers, indicating the viability of CLTV as a competitive alternative. Additionally, the formaldehyde emission from CLTV measures at a minimal 0.010 mg/m3, while total volatile organic compounds are limited to 47 μg/m3. The development of CLTV emerges as a sustainable solution to the shortage of high-quality solid wood resources. Its comparable performance to traditional materials such as CLT positions CLTV as an eco-friendly alternative for engineered wood products applicable in diverse global building systems. The minimal formaldehyde emission and low volatile organic compounds further emphasize the potential positive impact of CLTV on both the construction industry and broader environmental sustainability initiatives worldwide. This study sets the stage for advancing engineered wood products, addressing resource constraints, and contributing to sustainable practices in the global construction sector.

Optimization design and analysis of the broadband acoustic absorber of the microperforated panel with an interpolated straight tube

The microperforated panel (MPP) structure is widely used in the field of noise reduction. The traditional MPP structure has a fixed absorption peak, and the optimized MPP structure has an improved absorption band, but the frequency range of the absorption is not ideal. For the design of broadband absorption in MPP structures, this paper presents a MPP acoustic absorber structure (N-MH) with an interpolated straight tube (IST) designed for superior broadband acoustic performance. The N-MH structure combines the advantages of the MPP and the embedded necked Helmholtz resonator, as well as having a sub-wavelength thickness of only 60 mm, which is only 1/14th of the wavelength at the first resonant frequency. The N-MH structure is optimized based on the particle swarm optimization (PSO) algorithm. In comparison to traditional microperforated panel structures, the N-MH structure exhibits a significantly broader sound absorption frequency band. Additionally, we thoroughly investigate the factors influencing the mid-low-frequency sound absorption performance of the N-MH structure. Through theoretical prediction, simulation analysis, and experimental testing, it is verified that the N-MH structure has excellent broadband sound absorption characteristics in the frequency interval of 0–2000 Hz, and the percentage of sound absorption bands with absorption coefficients exceeding 0.9 can reach 78.2%.

Vibration reduction technology using modal energy propagation analysis method

Since the noise generated by mechanical structures affects the merchantability, it is important to predict the noise and vibratory characteristics at the first design stage. The frames and panels or trim parts in automobiles are coupled systems of the rigid and flexible substructure. In these systems, vibration of the flexible structures often becomes one of the major noise sources when the excitation force is applied to the rigid structure. FEM and modal analysis technique are not sufficient to carry out the effective low noise design in higher frequency because of high modal density and complexity of mode shape. Modal energy propagation method, proposed in this paper, is based on the mode synthesis method and the vibration power flow between the eigen modes of the rigid and flexible structures. Previous studies have verified that the vibration level can be reduced by extracting modes that contribute highly to the vibration power flow between subsystems and changing their characteristics. In this report, we present the results of applying this method to a coupled system of a body and panel structures in automobiles and verifying its validity. The structural modifications obtained from this analysis method were verified for their effectiveness in decreasing vibration.

Numerical prediction of the sound transmission loss of double panel configurations with acoustic structured and poroelastic materials

The sound transmission loss of multilayer system assemblies made of Noise Control Treatments comprising metamaterials and poroelastic materials, sandwiched between two structural panels is of utmost importance in aerospace, automotive, building and several other engineering applications. The integration of acoustic metamaterials in these systems introduces a number of challenges at the level of numerical simulation in order to predict their acoustic and structural behavior. This paper presents a methodology for the numerical simulation of the sound transmission loss of structural configurations comprising acoustic metamaterials embedded in a glass wools layer, sandwiched between two elastic panels. The metamaterial is designed as a parallel assembly of four sub-metamaterials. Each of these sub-metamaterials is also a series assembly of a periodic unit cell having a neck + cavity + neck type configuration. The four sub-metamaterials are designed so that their first resonance frequencies are grouped together in order to improve the sound transmission loss at the first two natural frequencies of the double panel. The COMSOL Multiphysics finite element method solver is used. The normal incidence and diffuse field sound transmission loss numerical results are presented and discussed in comparison with results from literature for validation.

Structural optimization and performance testing of concentrated photovoltaic panels for pavement

Solar pavement can convert sunlight shining on the pavement surface into clean electricity through photovoltaic panels, thereby transforming the energy structure of road transportation. In order to balance the light transmittance and anti-skid resistance of the solar pavement surface, this study proposed a concentrated photovoltaic panel (CPP) structure for pavement. The panel structure was optimized, and a laboratory model was developed. The mechanical properties and durability of the panel were tested by the multi-functional material test system (MTS) and the model mobile load simulator 3 (MMLS3). Furthermore, the electrical performance was evaluated by an outdoor test, followed by an economic evaluation. The results show that the optimal structural dimensions of the CPP for pavement are 540 mm long × 540 mm in length × 144.62 mm in thickness. The maximum flexural tensile strength of its anti-skid concentrated panel is 61.67 MPa, satisfying the requirements of the traffic load. After 1.35 million cycles of loading, the surface of the anti-skid concentrated panel is free of cracks and deformation and has no obvious wear, exhibiting good transmittance durability and excellent wear resistance. In addition, the overall structure of the panel counteracts the light loss effect of the material and improves the light concentration performance, providing a gain effect on the power generation of the panel, especially in the case of high irradiance. The return on investment (ROI) of CPP for pavement is 54.42%, with cost recovery in 9.87 years. The levelized cost of energy is 0.67 CNY/kWh, indicating significant economic benefits. At the same time, 1539.3 kg/m2 of CO2 emissions can be avoided during the operation cycle, and the environmental benefits are also considerable. This study can provide a reference for the promotion and application of photovoltaic power generation technology in road engineering.

A Multi-Layer Micro-Perforated Panel Structure Based on Curled Space for Broadband Sound Absorption at Low Frequencies

A Multi-Layer Micro-Perforated Panel Structure Based on Curled Space for Broadband Sound Absorption at Low Frequencies

Experimental and Numerical Investigation of the Shear Performance of an Innovative Keyway Joint for Prefabricated Concrete Wall Panels

To improve the shear performance and construction efficiency of horizontal joints in prefabricated concrete wall panel structures, an innovative keyway joint for prefabricated concrete wall panels is presented to maximize the contact area and joint friction, enhancing both the shear performance and the installation efficiency. Shear tests on eight prefabricated concrete wall panels were conducted to investigate the effects of the axial compression ratio, interface mortar strength, and keyway depth on the shear performance of these novel joints. Concurrently, a finite element model for prefabricated concrete wall panel keyway connections was established via ABAQUS, and a parametric analysis approach was employed to study various factors such as the axial compression ratio, the interface mortar strength, and the keyway construction type, as well as their impact on the shear performance of joints. The findings showed that, as the axial compression ratio increased, the failure mode of the keyway joint transitioned from shear brittle failure to compressive shear plastic failure, accompanied by evident crack propagation. The recommended keyway depth parameter remains between 40 and 80 mm, with the inclination angle of the keyway joint ideally ranging from 0° to 20°. Compared to the straight joint, the shear capacity of the innovative keyway joint increased by 16.5%.

Investigation of mechanical properties and elucidation of factors affecting wood-based structural panels under embedment stress with a circular dowel II: detailed observation for plywood and OSB using DIC and CT scanning

Although embedment properties are vital to timber engineering, the behavior and strain distributions in wood-based panels have not been clarified in detail. Our early studies suggested four possible causes of failure behavior and strain distribution: (i) two types of failure behavior (in-plane and out-of-plane failure); (ii) enlargement of the stress-spreading range with increasing load step; (iii) reduction of the stress-spreading range (normalized by dowel diameter) with increasing dowel diameter; and (iv) preferential stress spreading in the vertical and horizontal directions along the strong and weak-axis specifications, respectively. However, these hypotheses were not supported by actual observations. The present study aims to observe and clarify the surface strain distribution via digital image correlation and the internal failure behavior via computed tomography scanning. Most results of the wood-based panel specimens (plywood and oriented strand board) did not contradict the above hypotheses. The failure behaviors of plywood and oriented strand board are likely determined by the direction of the veneer fibers and the layer’s position, respectively. Within the strong axial layer of plywood, fibers on both sides of the dowel were densified by fibers dissociated immediately above the dowel, whereas the weak axial layer in plywood was deformed like a timber under partial compression perpendicular to the grain. In contrast, oriented strand board under an embedding stress exhibited a circularly distributed strain and a dispersed void area in its outer layer. Densification was observed only in the inner layer.

Nonlinear modelling parameters for performance-based seismic evaluation of existing wood light-frame buildings in Canada

The mechanical behaviour of wood light-frame shearwalls is difficult to explain unless system-level performance is taken into account. Although the behaviour of wood light-frame shearwalls with wood structural panels is consistent with and represented by the behaviour of the panel to framing nail joints, comprehensive seismic evaluation guidelines for Canadian practice are currently lacking. This study presents a critical review of the available literature on the performance-based seismic evaluation of wood light-frame buildings through nonlinear analysis approach. To verify the applicability of these standards in Canada, the procedure outlined in these documents is compared to available experimental testing. Nonlinear pushover analysis is performed on two representative wood light-frame buildings in Montréal and Vancouver. Results are compared, and further discussion is provided on the adequacy of each document to Canadian practice.

Hydroelastic response of Froude scaled stiffened steel panels exposed to design-critical wave slamming

Stiffened steel panels of offshore ocean structures may experience violent wave impacts which needs to be accounted for in design. The slamming pressures are often measured in scaled wave tank tests and imposed on finite element models to obtain local structural responses. These responses are sometimes high, which has raised the question if hydroelastic effects are properly accounted for. One way to address the uncertainty of hydroelasticity, is to carry out hydroelastic model tests and compare measurements statistically with FEA calculations. This paper presents the hydroelastic model tests required for this type of comparison. Approximate elastic panels representing Froude scaled stiffened steel panels were 3D printed, validated, and then installed in a vertical column in a wave tank. The elastic panels were exposed to design critical wave slamming during irregular wave conditions relevant for the North Atlantic. Two different elastic panels were tested, one strong and one weak panel. The hydroelastic response of the elastic panels are reported in detail and shows that the panel responds with a limited set of frequencies. In most cases the strain time series of the stiffeners and girders obtain its maximum value during the first half period of vibration. Furthermore, the vibration of the panels generally show strong decay after the time of maximum strain. The extreme strains fit reasonably well with the Gumbel distribution. Furthermore, the variability of the extreme strains, measured as the coefficient of variation (COV), is comparable to the variability of slamming pressures from literature, for the strong elastic panel, but is found to be reduced significantly for the weak elastic panel.