Perforation Of Panels Research Articles

A Comprehensive Framework for Integrating Robotics and Digital Twins in Façade Perforation

In contemporary design practices, the conflict between initial design approaches and subsequent manufacturing and construction stages presents a notable challenge. To address this disparity, our study aims to establish a comprehensive digital design workflow, bridging these gaps. The authors introduce a conceptual framework that seamlessly integrates the imperatives of LEED with the realm of robotic manufacturing, specifically tailored for construction sites. The proposed methodology encompasses four distinct iFOBOT modules: iFOBOT-environment, iFOBOT-design, iFOBOT-construct, and iFOBOT-monitor. The integration of these modules allows for a holistic approach to design and construction, fostering efficient collaboration between multidisciplinary teams. To validate the efficacy of the author’s approach, we conducted an empirical study involving the creation of a double-skin facade panel perforation using this integrated process. Initial findings emphasize the enhanced constructability achieved through simulated robotic interventions utilizing a heuristic function. Moreover, this research presents a functional prototype as a tangible embodiment of the method’s practical application and potential impact on the field of architectural design and construction.

Insert loss experiment and acoustic impedance theoretical study on the noise barrier with MPP-QRD top structure

The effective edge processing is the key to the performance of noise barrier. To prevent the sound diffraction within the low-medium frequency range, the quadratic residue diffuser (QRD) was combined with microperforated panel (MPP) in this study. The impedance of MPP with different parameters and QRD structure with N = 7 was calculated respectively and the matching degree of the composite structure was obtained. The insertion loss of noise barriers with different MPP-QRD top structures was field measured and compared to the equi-height vertical noise barrier. The results show that the degree of impedance matching between microperforated panels and quadratic residue diffusers is significantly correlated with their performance as the top structure of noise barrier. The acoustic impedance matched MPP-QRD top structure can significantly improve the insertion loss of the vertical noise barrierwith the same height. When the microperforated panel perforation is 3 %, the thickness is 0.8 mm, and the aperture is 0.6 mm, performance of the MPP-QRD structure is the best, the relative insertion loss can reach 4.07 dB.

Optimization of sound-absorbing and insulating structures with 3D printed recycled plastic and tyre rubber using the TOPSIS approach

Studies on recycled materials emerged during recent years. This paper investigates the properties of sound absorption and transmission loss of the structures of the perforated plastic panel (PPP) backed with the rubber granule panel (RGP). Under production conditions, such a structure could be produced using only waste. The normal incidence sound absorption and transmission loss of the structure was measured using ISO 10534-2 and ASTM E2611-17 standard methods, respectively. In this study, the plastic panel perforation holes were tilted in steps of 15°–45° compared to the vertical axis of the sample. Different thickness rubber panels were used as backing (12 mm, 22 mm and 27 mm). The results showed that the sound absorption and transmission loss increased with the angle of the perforation pore. To compare the different structures, the multi-criteria analysis using the technique for order of preference by similarity to ideal solution (TOPSIS) approach was done. The RGP thickness, sound absorption coefficient (SAC) and sound transmission loss (STL) were weighted as a criterion. The results of the multi-criteria analysis showed that the optimal structure for a possible application is PPP45°+ RGP 22 mm, which was ranked highest of all alternatives. The first peak of SAC reached 0.97 at 1000 Hz. In the frequency range of 250–1000 Hz, STL values reached up to 10.4 dB and in the frequency range of 1–4 kHz – 20.1 dB. The results obtained using RGP and PPP show promising development potential for sound absorption and insulation applications.

Experimental investigation on the perforation behaviour of sandwich panels with hybrid composite face sheets and cellular aluminium core using quasi-static and instrumented inverse impact methods

With the rising demand for lightweight and high-performance shielding systems, sandwich panels made of thin rigid face sheets and cellular material cores have recently received much attention. The present study aims to investigate the perforation behaviour of lightweight sandwich panels made of fibre reinforced composite face sheets and aluminium foam core under quasi-static and dynamic testing conditions. A particular focus is made on the fibre hybridization effect on the overall panel behaviour. Impact perforation tests were conducted using an inverse perforation technique. Instead of conventional free-flying projectile impact tests, studied samples are fixed in a hollow projectile. Then, this assembly is accelerated toward an instrumented steel perforator replacing the incident bar of a split Hopkinson pressure bar. Consequently, this modified split Hopkinson pressure bar system can be used as both a perforator and a measuring device. Therefore, the piercing force-displacement curves, the energy absorption capability as well as the penetration and damage mechanisms of the tested panels was analysed and compared to quasi-static perforating tests. To better assess the testing results, quasi-static tensile and bending tests were carried out on the face sheets materials. Moreover, quasi-static and dynamic compression tests were performed on the aluminium foam core using conventional test methods and direct split Hopkinson pressure bar. Unlike the aluminium alloy face sheets, the experimental findings revealed that the sandwich panels with composite face sheets demonstrated higher rate sensitivity, better perforation resistance and specific energy absorption capability. Results have also shown that the hybridization of carbon and glass fabrics combined their best tension and bending properties as well as their higher dynamic strength, which has increased the sandwich panel's perforation resistance.

On optimum perforation layout in low-rise steel plate shear walls

The design and performance of Steel Plate Shear Walls (SPSW) strongly depends on infill panels. Any unnecessary increase in the thickness of infill panels, which is a common occurrence in low-rise buildings, results in extremely large boundary elements and a noneconomic design. Among the several remedies that have been proposed and discussed by researchers, infill panel perforation has become more popular in SPSW design and construction. As a designer, one should primarily choose a desirable perforation layout, then adopt an approximate stiffness reduction formula and try to replace the infeasible design infill panel with a perforated one which possesses a minimum practical thickness and provides a similar lateral stiffness and strength. In this paper for a 4-story SPSW, primarily designed with practically infeasible thin infill panels, the optimum perforation diameters corresponding to diverse diagonal and rectangular perforation layouts are explored and the results have been compared to those provided by the available stiffness reduction formulas. The optimization outcomes reveal that the uniformly spaced rectangular perforation layouts are more efficient in the sense of SPSW stiffness reduction. Also, the efficiency of stiffness reduction formulas for rectangular perforation layouts have been assessed and the reliable methods introduced. Finally, on the basis of the resulted optimum sets, some formula improvements and design recommendations are concluded which would be useful and beneficial for practicing engineers.

Perforated steel plate shear walls with curved corrugated webs under cyclic loading

Steel Plate Shear Walls (SPSWs) are traditionally designed with vertical infill plates, which are connected to the surrounding frame and can be stiffened or unstiffened. Recently, the application of plates with different geometrical shapes and perforations has attracted the attention in the literature with the aim of understanding the behavior of high-performing SPSW systems. However, detailed and systematic investigations are still required to fully understand the behavior of such relatively new lateral-force-resisting systems, further complicated by the introduction of perforations. This paper addresses this issue, with the structural performance of curve-corrugated SPSWs with centrally-placed opening being the subject of investigation. The research described herein describes 128 nonlinear finite element models of SPSWs, analyzed under cyclic and monotonic loading. The effects associated with web corrugation angle, thickness, and opening size on the buckling, yielding, strength, and stiffness performances, hysteresis behavior, and energy dissipation characteristics of SPSWs are investigated. It is shown that consideration of 90° corrugation angle and larger web-plate thicknesses can be beneficial. However, having a panel perforation layout as a web plate and increasing the perforation size can adversely affect the performance of such systems. Overall, curved-corrugated SPSWs with web perforations are found to be a good structural system, and a desirable performance can be ensured through proper design variables and detailing each component of the system.

The effect of front pattern perforation shape on thermal sensations of occupants in personalized ventilation systems

The aim of this study was to find the most favourable shape of the front panel perforation shape, which would allow us to obtain the greatest cooling effect and – at the same time – be positively perceived by the people. The capacity of the personalized ventilation (PV) system to affect human thermal sensation, with different shapes of front panel perforation used, was analyzed.Once the pilot study was conducted, it used a rectangular nozzle of front pattern size 320 mm × 125 mm and six different front patterns perforation shapes with round holes were tested. Operational parameters such as: airflow 20 l/s, supply air temperature at 24 °C or ambient temperature at 28 °C were invariable. The experiment consisted of a two-stage analysis of air jets characteristics and of tests in which people participated. Twenty-five male volunteers, at the age of 22–23 were engaged. They their assessed thermal sensation and completed relevant questionnaires.On the basis of the results of the above study, differences in jet characteristics depending on the pattern shapes and their different impact on thermal sensation of the volunteers were demonstrated. The biggest cooling effect was obtained using front panels with small hole size (d = 5 mm). These perforations allowed us to obtain a more even air outflow from the entire panel. This ensured a broader airflow of lower velocity, reaching and affecting a larger area. With holes of larger size (d = 15 mm), air outflow occurred mainly through the central part, which produced narrow jets of higher velocity.

Mechanical behavior of carbon nanotubes-based polymer composites under impact tests

This study was focused on the effect of carbon nanotubes on the impact resistance and damage evolution in laminate carbon nanotubes/epoxy composites under an impact loading. The composite panels were made from carbon fibers and carbon nanotubes randomly distributed into epoxy resin. The amount of carbon nanotubes dispersion was varied up to 4% by weight. Taylor impact tests were carried out to obtain the impact response of specimens with dimensions of 70×70×4 mm3. A projectile manufactured from a high strength and hardened steel with a diameter of 20 mm and 1.5 kg of mass was launched by a compressed gas gun within the velocity of 3 m/s, 7 m/s and 12 m/s. For the experimental test, three velocity levels were used: 3 m/s for the elastic deformation, 7 m/s for the penetration of the impactor and 12 m/s for the perforation of panels. Deformation histories and damage modes in specimens were recorded during the impact test using a high-speed camera. Processing of carbon nanotubes dispersed in laminates, testing, damage, and key findings is reported. It is observed that the impact resistance of laminates reinforced with a random distribution of carbon nanotubes increases up to 15.6% at high-strain rate compared with that of 0% of carbon nanotubes. It is also observed that the resistance to damage initiation and evolution increases with the addition of carbon nanotubes concentration.

Numerical study on the hard projectile perforation on RC panels with LDPM

This paper numerically investigates the medium-caliber hard projectile perforation of steel rebar reinforced concrete panels by using the recently developed Lattice Discrete Particles Model (LDPM). With mesoscale constitutive laws governing cohesive fracture, strain hardening in compression and compaction due to pore collapse, LDPM naturally captures the failure mechanisms at the length scale of coarse aggregate of concrete. A constant area and shape partition method for circular cross-section is employed to determine the Gauss integration points distribution for beam elements. The sliding friction model for rebar-concrete interaction, in conjunction with LDPM for concrete are utilized for RC panel perforation modeling. Simulations of normal and high strength concrete panel perforation tests are carried out to validate the numerical model whereby agreement with the experimental data is achieved in terms of projectile residual velocity as well as damage contour. Extensive simulations are further performed to investigate the effect of projectile impact location and reinforcement on high strength concrete (HSC) panel perforation responses. Comparative numerical studies indicate that the projectile residual velocity is significantly reduced when the projectile hits the reinforced rebars. Furthermore, the reinforcement can considerably limit the damage area, crack openings and prevent the concrete shelter from structural failure. Finally, the LDPM simulations of HSC panel perforation are combined with cavity expansion analysis to achieve the RC perforation analytical model whereas the target resistance parameter R (Forrestal et al., 2003) is determined a672 MPa while the shear plugging thickness value is estimated as 33 mm for the cases of interest.

Experimental Investigation of the Ballistic Response of Composite Panels Coupled with a Self-Healing Polymeric Layer

AbstractIn this study, multifunctional panels with structural and self-healing capabilities were experimentally investigated under high velocity impact conditions. The panels were composed of two layers, one made of fiber-reinforced plastics (FRP) and the other of a self-healing ionomer, assembled in four different configurations with surface density ranging from 6.85 to 7.49 kg/m2. A total number of 16 impact experiments are reported, where spherical aluminium projectiles with diameters from 2.3 to 4.5 mm were shot at impact velocity, which varied from 2.0 to 2.5 km/s. The panel response was analysed in terms of (1) impact damage; and (2) capability to protect equipment located behind the panel from the cloud of fragments ejected downrange after panel perforation. Successful hole sealing was observed in panels consisting of a carbon FRP laminate and ionomer plate hit by projectiles up to 3.5 mm in diameter. The damage of the target was somewhat smaller when the ionomer was on the panel’s rear side. Suc...

Optimization of two-component armour

Abstract The paper presents research on optimization of two-layer armour subjected to the normal impact of the 7.62x54 B32 armour piercing (AP) projectile. There were analysed two cases in which alumina Al2O3 was supported by aluminium alloy AA2024-T3 or armour steel Armox 500T. The thicknesses of layers were determined to minimize the panel areal density whilst satisfying the constraint, which was the maximum projectile velocity after panel perforation. The problem was solved through the utilization of LS-DYNA, LS-OPT and HyperMorph engineering software. The axisymmetric model was applied to the calculation in order to provide sufficient discretization. The response of the aluminium alloy, armour steel and projectile material was described with the Johnson-Cook model, while the one of the alumina with the Johnson-Holmquist model. The study resulted in the development of a panel optimization methodology, which allows the layer thicknesses of the panel with minimum areal density to be determined. The optimization process demonstrated that the areal density of the lightest panel is 71.07 and 71.82 kg/m2 for Al2O3-Armox 500T and Al2O3-AA2024-T3, respectively. The results of optimization process were confirmed during the experimental investigation.

Impact perforation of sandwich panels with Coremat®

Analytical solutions for the quasi-static and low-velocity perforation of sandwich panels with woven roving E-glass/vinyl ester facesheets and Coremat were derived. A multi-stage perforation process involving delamination, debonding, core shear fracture and facesheet fracture was used to predict the quasi-static failure load and ballistic resistance of the panel. The high core-crushing resistance and damping of the Coremat resulted in rupture of the distal facesheet before the incident facesheet during panel perforation because they limited the amount of local indentation compared with global panel deformation. Analytical predictions of the quasi-static load-deflection response and the dynamic contact force history were within 10% of the test results.

Evaluating impact damage in CFRP using fibre optic sensors

Damage in unidirectional carbon/fibre composite resulting from both low and high velocity/energy impacts was evaluated using embedded fibre Bragg grating (FBG) sensors, C-scan and microscopic analysis. It was found that the FBG sensors located 10 mm from the impact site could detect residual strains from a 0.33 J (1.3 m s −1) impact which was not detectable by C-scan or visual inspection. The measured residual strain increased with impact energy and damage changed from matrix cracking to severe delaminations. High velocity impacts (225 m s −1, 11 J) resulted in test panel perforation and delaminations. FBG sensors located within a distance of 2–3 the damage radius detected residual strain from the impact. With an array of embedded sensors it is believed that it will be possible to identify the site of both low and high velocity energy impacts and predict the damage from the response of the adjacent sensors providing the sensors are located sufficiently close to the impact site.

LOW VELOCITY PERFORATION BEHAVIOUR OF POLYMER COMPOSITE SANDWICH PANELS

The paper describes low-velocity impact tests on square panels made from two polymer composite sandwich constructions, namely woven glass vinyl ester skins with Coremat core and woven glass epoxy pre-preg skins with honeycomb core. The impact velocity was up to 8 m s -1 with an impact mass of up to 30 kg giving a maximum impact energy of 882 J. This maximum energy gives full perforation of the panels. The panels were 0.5 m by 0.5 m with clamped but free to pull in boundary conditions. The impactor geometry considered was a 50 mm diameter hemisphere. Results are expressed in the form of energy and failure mode plots and it is shown that the energy absorbing capabilities of the panels increase with the velocity of impact. The increase in energy absorption is attributed to an increase in the core crush stress and skin failure stress at high strain rates. Some discussion is given on the influence of the energy absorbing capabilities of constituent materials on the overall energy absorption behaviour of the panel. Suggestions have also been made for increasing panel perforation energy.