Behavior Of Panels Research Articles

A simplified homogeneous approach for non-linear analysis of masonry infill panels under in-plane loads

This paper aims to create a unified model that effectively combines continuous 2-dimensional elements and discrete components to capture the nonlinear characteristics and failure mechanisms of solid and perforated masonry infill panels. Given that masonry infill behavior is primarily influenced by shear deformations, an equivalent model is developed by using multiple small square panels arranged diagonally and interconnected by two-component springs, encompassing axial and shear behavior at their intersections. For the sake of simplicity, the divided panels are assumed to behave elastically, with plasticity concentrated only in the axial component of the connector springs. Plastic behavior in the boundary elements was considered to involve both flexural and shear plastic hinges to provide an accurate estimation of the entire infill panel's behavior. To validate this approach, the simplified model is benchmarked against eight experimental masonry infill panels surrounded by steel or reinforced concrete frames and with or without openings. The results including global behavior and crack pattern were compared with available numerical predictions based on finite element method from the literature in addition to experimental outcomes. Ultimately, this comparison demonstrated that the homogeneous model could effectively predict the non-linear lateral behavior of the panels and accurately forecast crack patterns. Additionally, the use of unidirectional non-linear springs and the appropriate arrangement of elastic panels significantly reduced both pre-processing and analysis time.

Experimental verification of FRP bridge deck's monitoring system based on DFOS sensors

AbstractThe paper presents the smart FRP composite bridge panel called „OptiDeck“ with integrated distributed fibre optic sensors (DFOS), to monitor the panel's behavior. The panel is intended for use in newly build and refurbished road bridges. From structure point of view the uniqueness of the presented solution results from innovative technological production process to create a honeycomb core in thick sandwich panel. In order for the monitoring system to cover the entire surface of the panel and to detect local damage, it was necessary to use a modern solution based on geometrically continuous DFOS system. The DFOS system serves as the structure health monitoring (SHM) system, which has been tested during the production and laboratory testing of a prototypes in natural scale. The advantages of DFOS measurements are well known and applied in many civil engineering applications. However, the potential benefits are still not fully utilized. Finally the experimental verification of the DFOS system integrated with the FRP deck panel is presented.

Step-By-Step Guide to Model Photovoltaic Panels: An Up-To-Date Comparative Review Study

The presented study conducted a substantial literature review regarding the electrical modeling of photovoltaic panels. All the main models suggested in the literature to predict a photovoltaic panel's electrical behavior were reviewed, and diode-based equivalent electrical circuit models were selected for further investigations. The study performed a step-by-step investigation, comparison, and classification, followed by an in-depth and critical analysis of the art state. All the main diode-based models suggested in the literature were classified. The models' unknown parameters and the corresponding extraction methods were introduced and compared based on their accuracy, computing costs, and applicability. Reviewing the literature indicates that the extracted parameters under standard test conditions must be adjusted to actual environmental conditions to precisely predict a photovoltaic panel's behavior. By taking that into account, all the applied modifications in the literature were introduced and categorized. Finally, the reviewed documents were assessed critically to identify the research gaps and challenges. The analysis noted that although intensive research studies have been done, there are still many challenges to be faced. Thus, some directions for future research are proposed to cope with the remaining shortages. The presented study could be considered a step-by-step guide for anyone who wants to model the electrical behavior of photovoltaic panels under any environmental conditions.

Visualization of the Process of Static Buckling of a Micropolar Meshed Cylindrical Panel

Process visualization of static stability loss in mechanics is shown by the micropolar meshed cylindrical panel example with two families of mutually perpendicular ribs. The mathematical model of the panel's behavior is based on the Kirchhoff-Love hypotheses. The micropolar theory is applied to ac-count for scale effects. Geometric nonlinearity is taken into account according to the theory of Theodor von Karman. The mesh structure is taken into account based on the Pshenichnov I. G. continuum model. Visualization of numerical results using Autodesk 3ds Max software made it possible to more clearly assess the phenomenon of static buckling of the shell in question. Visualization of the results using 3D made it possible to establish that an in-crease in the distance between the edges of the mesh panel and an increase in the parameter depending on the size does not change the bending shape of the panel, as well as the diagrams of moments and forces at subcritical and supercritical loads.

Flexural properties of sandwich composite panels with glass laminate aluminum reinforced epoxy facesheets strengthened by SMA wires

Sandwich composite panels are widely used and significant in structural applications such as aerospace, shipbuilding and transportation, etc. This is due to their specific properties such as specific stiffness, strength and energy absorption. Still, many innovations are required to develop and upgrade their mechanical properties in various loadings and conditions, specifically in bending loads. One of the methods to enhance the properties of sandwich structures is to employ various advanced materials in these structures to change their acquired properties. In the present research work, sandwich composite panels made by fiber metal laminate like glass laminate aluminum reinforced epoxy (GLARE) as the facesheets and PVC polymer foam as the core material are investigated in flexural (bending) loading condition. To change or enhance the behaviour of sandwich panel in bending loads, shape memory alloy wires are also embedded in between glass fiber reinforced epoxy composite layers in fiber metal laminate facesheets. The shape memory wires are also pre-strained in fiber reinforced epoxy composite in sandwich panels. To study the flexural properties of sandwich panels with fiber metal laminate facesheets, the effect of shape memory alloy wires and also the effect of pre-straining of the wires, three types of sandwich panels are considered and made including panels without shape memory alloy wire, two wires with 0% tensile pre-strain, and two wires with 5% tensile pre-strain for the same cross section. Due to the importance of bending properties in structural applications, the sandwich composite specimens are subjected to flexural test according to ASTM standards. The maximum of 13% increase in maximum bending load and 84% increase in breaking load for the specimens with 0% pre-strained wires are achieved. Also, the maximum displacement and the energy absorption for the specimen with 5% pre-strain was enhanced by 26.5% and 37%, respectively. The energy absorption during the flexural test is greater in case of the specimen with pre-strained wires. Moreover, the specimens with pre-strained wires show better integrity of the structure after the failure in bending. The results represent the advantage effect of shape memory alloy wires on sandwich composite panel's behaviour in bending.

Evaluating Elastic Modulus and Thrust Force of Semi-Interlocking Masonry Panel

The semi-interlocking masonry (SIM) system has developed in Masonry Research Group at the University of Newcastle, Australia. The SIM panels dissipate energy through the sliding friction on bed joints of SIM units during earthquake excitation. To model the SIM panel's behaviour numerically some key parameters need to evaluate experimentally. This study investigates the elastic modulus of SIM prism and thrust force for horizontal and vertical arching during out-of-plane deflection. Three types of bricks were used in tests: topological SIM, mechanical SIM, and without interlocking bricks. In addition, the prisms of topological SIM bricks comprising three and five bricks have been used to find out the mechanical properties of units. This paper presents the results of 18 arching tests: six tests with topological interlocking, six tests with mechanically interlocking units, six tests with ordinary bricks, and 11 prisms of topological SIM bricks for compressive and modulus of elasticity test.

Evaluating elastic modulus and thrust force of semi-interlocking masonry panel

The semi-interlocking masonry (SIM) system has developed in Masonry Research Group at the University of Newcastle, Australia. The SIM panels dissipate energy through the sliding friction on bed joints of SIM units during earthquake excitation. To model the SIM panel's behaviour numerically some key parameters need to evaluate experimentally. This study investigates the elastic modulus of SIM prism and thrust force for horizontal and vertical arching during out-of-plane deflection. Three types of bricks were used in tests: topological SIM, mechanical SIM, and without interlocking bricks. In addition, the prisms of topological SIM bricks comprising three and five bricks have been used to find out the mechanical properties of units. This paper presents the results of 18 arching tests: six tests with topological interlocking, six tests with mechanically interlocking units, six tests with ordinary bricks, and 11 prisms of topological SIM bricks for compressive and modulus of elasticity test.

Measurement of the “IBUKI” Solar Array Panel's Behavior Using High Precision Image Processing

Generally, many space satellites have large solar array panels for power generation and large antennas for observation and communication. The panels and antennas must be lightweight because of the payload weight limit of the launch vehicle. So, they are very flexible, with little damping ability. This results in vibrations cause serious problems. When the thermal environment around a flexible structure on orbit such as a solar array panel changes to cold or hot, the flexible structure produces its own deformation or vibration. These occur most often during rapid temperature changes called thermal snap or thermally-induced vibration, which has been known to cause attitude disturbance in Low Earth Orbit (LEO) satellites. Thermal snap vibration occurring on a flexible solar array panel is very slow. It is very difficult to measure thermal snap motion by sensors such as accelerometer. The behavior of a space structure affected by thermal snap has never been observed directly in space so far. This report presents the measurement results of “IBUKI” solar array panel's behavior using monitor camera.

Structural performance of a multifunctional spacecraft structure based on plastic lithium-ion batteries

A multifunctional structure reduces the mass and volume of a spacecraft through the removal of parasitic components of a functional structure, such as the purely structural “packaging” of the battery. Commercially available cells, of the plastic lithium-ion type, may be incorporated into structural sandwich panels, eliminating the need for a secondary structure in the battery subsystem. Locating the cells in the structure also removes them from the bus, which reduces the volume of the craft and, consequently, reduces the mass of the primary structure. Although the batteries studied in this work exhibited low mechanical properties, this paper will show that, by placing the cells carefully within the sandwich panel, structural performance is not compromised. Finite element models show a reduction in peak stress and deformation in multifunctional panels, compared to a conventional design, when a favourable layout is selected. Less conclusive results for peak acceleration, however, suggest that this type of multifunctional structure may not be appropriate for all applications. Comparison of the finite element modelling technique with a real panel's behaviour shows that the deformation and stress predicted by the model is consistent with reality, whilst the acceleration is reliable for low frequencies.

Design of Perforated Panels for Low Frequency Acoustic Correction of Rooms for Listening to Music

The acoustic design of rooms for listening to music or recording is a very difficult subject: in order to improve the acoustic performance of these confined rooms, it may be necessary to absorb noise energy; sometimes all audible frequencies of the spectrum, sometimes at some specific frequencies. The design is especially difficult at low frequencies, where both resonance modes and standing waves are present. For the correction of problems of this kind, a resonance cavity perforated panel can be used. In the technical literature, there are some theoretical models describing the behavior of such a panel, but the results given are scarcely informative. Here we try to develop a simple but accurate approach for the design of these devices. On the basis of a reference FEM simulation of a drilled panel which was discussed in a previous paper [4], an engineering analytical model, which can be simply implemented either in few lines of FORTRAN code or by means of free engineering software tools like OpenOffice.org , has been developed. The dependency of the panel's behavior on the design parameters is here discussed.

Estudio experimental de cargas sobre muros cartón yeso (Drywall)

This research studies the Drywall panel's behavior subjected to the action of horizontal loads. Furthermore this pretends to establish a comparison between the damage produced in the two systems (Drywall - Masonry) when they were submitted to horizontal loads. The research gave as a result that Drywall panels submitted to drift values about 0.5% had an acceptable behavior from the point of view of the damage present in this system compared to masonry nonstructural walls. Being Drywall panels nonstructural walls with larger inter story drift capacity than masonry walls, they emerge as a new alternative because of the requirements presented in NSR-98 (Norma Colombiana de Diseno y Construccion Sismo Resistente) about demand of drift.

Photovoltaic solar panels simulation including dynamical thermal effects

Power curves of photovoltaic solar panels are simulated using actual current—voltage characteristics of individual solar cells. Starting from the response of these large area p- n junctions to light flux and temperature, the effects of dispersion in cells on the panel's performance is analyzed. Thermal effects are considered, and the temperature of each cell can be associated with its operating conditions as a function of time. The corresponding loop introduced in the computation makes it possible to analyze the panel's behaviour using various loads under non equilibrium conditions on.