Plate Geometry Research Articles

Origami single-end capacitive sensing for continuous shape estimation of morphing structures

In this work, we propose a novel single-end morphing capacitive sensing method for shape tracking, FxC, by combining Folding origami structures and Capacitive sensing to detect the morphing structural motions using state-of-the-art sensing circuits and deep learning. It was observed through embedding areas of origami structures with conductive materials as single-end capacitive sensing patches, that the sensor signals change coherently with the motion of the structure. Different from other origami capacitors where the origami structures are used in adjusting the thickness of the dielectric layer of double-plate capacitors, FxC uses only a single conductive plate per channel, and the origami structure directly changes the geometry of the conductive plate. We examined the operation principle of morphing single-end capacitors through 3D geometry simulation combined with physics theoretical deduction, which deduced similar behavior as observed in experimentation. Then a software pipeline was developed to use the sensor signals to reconstruct the dynamic structural geometry through data-driven deep neural network regression of geometric primitives extracted from vision tracking. We created multiple folding patterns to validate our approach, based on folding patterns including Accordion, Chevron, Sunray and V-Fold patterns with different layouts of capacitive sensors using paper-based and textile-based materials. Experimentation results show that the geometry primitives predicted from the capacitive signals have a strong correlation with the visual ground truth with R-squared value of up to 95% and tracking error of 6.5 mm for patches. The simulation and machine learning constitute two-way information exchange between the sensing signals and structural geometry. By embedding part of the origami surface with morphing single-end capacitive sensors, FxC presents a unique solution that leverages both the mechanical properties of origami and sensing properties of capacitive sensing.

Automated optimization for steel mold of precast components based on multi-objective evolutionary algorithm

Designing an economical and reliable steel mold for precast concrete (PC) components can accelerate the promotion of prefabricated buildings. This paper presents an automated design framework for a steel mold of PC components to generate manufacturing information, including dimensions and location of each plate. The profile and dimensions of PC components are extracted from the shop drawings, and a finite element model of the steel mold is established and initialized. A multi-objective optimization model considering material usage and manufacturing convenience is developed to determine the geometry and quantity of plates in steel molds. The non-dominated sorting genetic algorithm II (NSGA-II) is applied to obtain a Pareto solution set for steel mold design. The production information in DXF format can be automatically generated by parsing Industry Foundation Classes (IFC) model. The cost-effectivity and practicality of the proposed framework were verified via the design case for a real PC stair mold.

Aeroelastic Stability and Design of Laminated Composite Sandwich MRE Plates Using Surrogate Metaheuristics Optimization

Sandwich composite materials with elastomeric cores and high-strength face layers have widespread applications in various engineering sectors as passive damping structural materials. This study examines the dynamic properties of sandwich plate with laminated composite face layers and smart magnetorheological elastomer (MRE) core under the action of the aerodynamic and hygrothermal loads. The dynamic model based on Kirchhoff’s plate theory is employed and the equations of motion are derived using Hamilton’s principle. The flow conditions are assumed supersonic and modeled by the first-order piston theory. The natural frequencies and aerodynamic pressure distributions are obtained from finite element model. Upon validating the model, the effects of various factors such as moisture, temperature and plate geometry on the critical aerodynamic pressure for different boundary conditions and magnetic fields are studied. Using these parametric data, a regression model is developed using Back-Propagation Neural Network to predict the critical aerodynamic pressure as a function of effective geometrical parameters. In order to enhance the aerodynamic stability, the critical aerodynamic pressure is maximized by the optimal selection of plate aspect ratio, face layer ply orientation sequence and core layer thickness ratio via the modified teaching–learning-based optimization (MTLBO) technique employing the trained neural network-based surrogate model. The approach is very convenient and it has been found that nondimensional aerodynamic pressure along with loss factor has improved almost twice. In the sensitivity analysis study, it is noticed that changes in aspect ratio around the optimal point have a relatively drastic effect on the critical aerodynamic pressure at all the face layer ply configurations.

The Effect of Perforated Plate Geometry on Thermofluid Characteristics of Briquette Drying Oven: A 3D Computational Fluid Dynamics (CFD) Study

The process of drying briquettes in an oven is very costly due to the amount of fuel, labor, and drying time required. Furthermore, inadequate air circulation also results in an uneven and ineffective drying process for briquettes. The performance of the briquette drying oven can be improved by changing the geometry of the perforated plate in the oven to optimize the air distribution. This research process was conducted through Computational Fluid Dynamics (CFD) simulations using Ansys Fluid Flow (Fluent) software by testing three different perforated plate geometries in the oven to determine their effect on the air distribution that occurred in the oven. The research findings indicate that the temperature, velocity, pressure, and airflow pattern of the air are all considerably impacted by the incorporation of perforated plates into the first, second, and third geometries of the oven. When compared to the original geometry, the average air temperature in ovens using the first, second, and third geometries increased by 6.86%, 7.38%, and 9.15%, respectively. Average air velocity increased by 226.04%, 235.77%, and 431.60% in ovens with the first, second, and third geometries. However, the air pressure in ovens with the first, second, and third geometries decreased by 11.05%, 8.62%, and 10.66%. The use of perforated plates on the right, back, and left sides in an oven with the third geometry is the best geometry produced in this research. This happens because this oven produces the most even airflow pattern in the oven compared to other geometries. In addition, the oven with the third geometry has the highest average temperature and average air velocity, with a lower average air pressure compared to the other geometries. Consequently, drying is more effective and takes less time.

Thermoviscoelastic modelling of highly reactive thermoset resins for liquid moulding applications

This paper presents a methodology for developing thermo-mechanical properties model for highly reactive resins and its use for Resin Transfer Moulding process (RTM) modelling and prediction of residual stresses. Cure Hardening Instantaneously Linear Elastic (CHILE), and Thermoviscoelastic (TVE) models, were implemented to analyze the mechanical behaviour of the resin. Simulation of the RTM process was developed and applied to a representative curved plate geometry. An integral approach was considered where the degree of cure gradient, generated during the filling stage due to the reactivity of the resin, was implemented as initial condition of the stress-deformation process simulation. The validation process included fabricating experimental parts with the representative geometry. The degree of cure variation of highly reactive thermosets during injection caused a significant effect on the final shape of the parts. These effects were captured by the simulations, where the TVE model showed a more accurate prediction of the part distortion.

Isogeometric free vibration of functionally graded porous magneto-electro-elastic plate reinforced with graphene platelets resting on an elastic foundation

This article investigates the free vibration behavior of functionally graded porous reinforced with graphene platelets magneto-electro-elastic (FGP-GPL-MEE) plates. The FGP-GPL-MEE plate is supported by the Winkler-Pasternak foundation and subjected to the initial external electric voltage and magnetic loads. The governing equations for FGP-GPL-MEE plates are derived from the combination of Hamilton's principle and the refined plate theory (RPT) with four variables. The FGP-GPL-MEE plate is formed by combining three porosity distributions of functionally graded materials and three patterns of graphene platelets dispersion distributed along the plate thickness. Using the modified Halpin-Tsai model, effective material properties of the FGP-GPL-MEE plate are estimated. Isogeometric approach (IGA) is used to discretize the plate geometry and extract mode shapes and natural frequencies. The effects of various parameters such as porosity distributions, porosity coefficient, GPLs distributions and magnetic and electric potentials on the natural frequencies of the FGP-GPL-MEE plate are performed. The results indicate that the GPLs reinforcement can be significantly enhanced the natural frequencies of the FGP-GPL-MEE plate. Moreover, the free vibration behavior is significantly influenced by porosity, as well as magnetic and electric fields. The results of this study provide valuable insights into the vibrational characteristics of FGP-GPL-MEE plates.

Influence of the carbon fiber plate curvature of advanced footwear technology on the running energetic cost and 3000-m performance

This study aimed to explore the effect of two similar commercialized advanced footwear technology models differing mainly in their plate geometry (i.e., low and high curvature plate) on the running energetic cost in both non-fatigued and fatigued states. It also sought to determine their impacts on 3000-m performance. Twelve highly trained male athletes performed four 5-min trials (two advanced technology models, two trials). In each experimental session, athletes completed a 3000-m trial which was followed by a 5-min trial to test the running energetic cost when fatigued. Athletes exhibited a lower running energetic cost when wearing the low curvature plate in a non-fatigued state (P = 0.034; − 1.13 [− 1.92 to − 0.11] %), which persisted with better performance in the 3000-m trial (P = 0.017; − 0.42 [− 0.74 to − 0.09] %). However, in a fatigued state, non-significant differences were reported (P = 0.207). The low curvature plate seems to be more effective than the high curvature plate when running at low intensity in a fresh state as well as in a maximal high-intensity effort. However, non-significant differences between plate geometries were observed when fatigue was increased.

Effect of microchannel cross-section geometry on the flow resistance with stainless steel flat-plate solar collectors

The stainless steel flat plate solar collector is a new type of collector that has a longer lifespan in high-temperature and high-humidity environments. When using stainless steel as the base material of the collector, the microchannel structure is typically employed to increase the heat transfer area and compensate for the lack of heat transfer coefficient of stainless steel. However, the shape of the channel section in microchannel structures affects the flow resistance of the heat transfer medium. This article presented the equation for the optimal feature size of the channel, obtained through fluid theory analysis of the stainless steel flat plate collector. The study analyzed the impact of different section parameters on the flow distribution and pressure drop characteristics of the medium in the channel through numerical simulation. The results showed that for a certain inlet flow rate, the cross-sectional geometry of the microchannel heat-absorbing plate determined the parameters such as the type of core cross-section, the degree of wall urgency, and the geometrical length of the microchannel, which in turn affected the distribution of the fluid in the flow channel and the energy loss. The optimal thermal performance of the stainless steel collector was observed when the width of the micro-channel was 8.7 mm and the corrugation height of the tube group was 3.00 mm.

Modelling the Influence of the Tube Support Plate on the Eddy Current Testing of the Steam Generator: Sensitivity Study & Validation

Eddy current testing (ECT) of Steam Generator (SG) tubes is part of the maintenance program of Nuclear Power Plants. Tube Support Plates (TSP) are usually only considered as extraneous signals for tube inspection. However, for long-term operation of SGs, there is a safety concern related to the build-up of deposits in the TSPs flow holes. The clogging-up of the TSPs flow holes affect the safe thermal-hydraulic operation of SGs. The deposits come from the feedwater train and are mostly iron oxides (magnetite) with a weak electrical conductivity and magnetite permeability.The ability of ECT probes to detect and characterize TSPs deposits is therefore of great interest. The most common and industrial ECT technique, the bobbin coil, averages the surrounding electromagnetic field over 360°, whereas the geometry of tri-foiled and quadri-foiled TSPs, and thus of clogging, is rather complex and non- axisymmetric, hence motivating the evaluation of the performance of conventional ECT rotating probes used for SGs tubes inspection. Although simulation is a powerful tool to support such a study, it requires dedicated models to be made available to NDT experts, and CEA develops ECT physical models in CIVA for this purpose. In addition to standard fast CIVA modules based on 3D semi-analytical or 2D numerical calculations restricted to canonical or axisymmetric parts, respectively, CEA develops a module dedicated to the simulation of SG tube inspection based on a 3D numerical simulation. This module allows tube deformation such as ovalization, bending or tube expansion. It also allows the addition of external objects such as anti-vibration bars, different geometries of tube support plates and now their clogging by deposits. This model is used to study various influent parameters and to perform benchmarks in the framework of a scientific collaboration between the CEA and the IRSN. Here, the specificity of the TSPs and their clogging justifies qualifying the simulation model before evaluating the influence of material and geometry properties of the deposit as well as the performance of the inspection techniques. We present the main features of the simulation module in CIVA, its experimental validation, and the main trends in the distortion of the simulated signal as a function of variation in the clogging description.

Prediction of fracture toughness using small specimens based on machine learning

In this study, a neural network was used to predict the fracture toughness of standard specimens of 16MnDR steel in the tough-brittle transition zone. The main factors such as specimen plate thickness and geometry type are taken as inputs to the network and the fracture toughness of the standard specimen is taken as output. A BP neural network is utilized to describe the nonlinear relationship between them. The network was trained and tested by using finite element simulation simulation data based on experimental data. The established neural network model was found to have good accuracy in predicting the experimental data and can be used as a method for predicting the fracture toughness of 16MnDR standard specimens.

Optimized Clavicle Hook Plate Geometry for Average Korean Clavicle–Acromion Dimensions: A Finite Element Analysis Study

Optimized Clavicle Hook Plate Geometry for Average Korean Clavicle–Acromion Dimensions: A Finite Element Analysis Study

Enhanced fabrication of size-controllable chitosan-genipin nanoparticles using orifice-induced hydrodynamic cavitation: Process optimization and performance evaluation

Chitosan nanoparticles (NPs) possess great potential in biomedical fields. Orifice-induced hydrodynamic cavitation (HC) has been used for the enhancement of fabrication of size-controllable genipin-crosslinked chitosan (chitosan-genipin) NPs based on the emulsion cross-linking (ECLK). Experiments have been performed using various plate geometries, chitosan molecular weight and under different operational parameters such as inlet pressure (1–3.5 bar), outlet pressure (0–1.5 bar) and cross-linking temperature (40–70 °C). Orifice plate geometry was a crucial factor affecting the properties of NPs, and the optimized geometry of orifice plate was with single hole of 3.0 mm diameter. The size of NPs with polydispersity index of 0.359 was 312.6 nm at an optimized inlet pressure of 3.0 bar, and the maximum production yield reached 84.82 %. Chitosan with too high or too low initial molecular weight (e.g., chitosan oligosaccharide) was not applicable for producing ultra-fine and narrow-distributed NPs. There existed a non-linear monotonically-increasing relationship between cavitation number (Cv) and chitosan NP size. Scanning electron microscopy (SEM) test indicated that the prepared NPs were discrete with spherical shape. The study demonstrated the superiority of HC in reducing particle size and size distribution of NPs, and the energy efficiency of orifice type HC-processed ECLK was two orders of magnitude than that of ultrasonic horn or high shear homogenization-processed ECLK. In vitro drug-release studies showed that the fabricated NPs had great potential as a drug delivery system. The observations of this study can offer strong support for HC to enhance the fabrication of size-controllable chitosan-genipin NPs.

A novel CFD model for design and performance prediction of recuperators for Indirect Evaporative Cooling

Indirect evaporative cooling (IEC) appears to be a highly promising technology for incorporating and/or substituting traditional air conditioning systems, as it can guarantee good cooling performance with a reduced environmental impact. In this study, a Computational Fluid Dynamics (CFD) model for design and performance prediction of recuperators for IEC systems with dry primary and secondary channels was developed. The model was validated against experimental data for a cross-flow recuperator, obtaining a maximum difference between numerical and experimental results of 4.9% for the secondary air outlet temperature, 5.3% for the primary air outlet temperature, and 8.1% for the dry-bulb effectiveness. After validation, the model was used to find a new plate geometry which guarantees a 12.5-15.9% improvement in the dry-bulb effectiveness, without an excessive increase in the pressure losses along the channels.

Force Metrology with Plane Parallel Plates: Final Design Review and Outlook

During the past few decades, abundant evidence for physics beyond the two standard models of particle physics and cosmology was found. Yet, we are tapping in the dark regarding our understanding of the dark sector. For more than a century, open problems related to the nature of the vacuum remained unresolved. As well as the traditional high-energy frontier and cosmology, technological advancement provides complementary access to new physics via high-precision experiments. Among the latter, the Casimir And Non-Newtonian force EXperiment (Cannex) has successfully completed its proof-of-principle phase and is going to commence operation soon. Benefiting from its plane parallel plate geometry, both interfacial and gravity-like forces are maximized, leading to increased sensitivity. A wide range of dark sector forces, Casimir forces in and out of thermal equilibrium, and gravity can be tested. This paper describes the final experimental design, its sensitivity, and expected results.

Residual stress relief strategy in thick steel weldments via local induction heat treatment: Simulation and neutron diffraction experiment

This study investigated the effect of local induction post-weld heat treatment (PWHT) on residual stress relief in thick submerged arc welded steel plates. A combination of numerical and neutron diffraction methods was used to examine the effect of various PWHT parameters, such as annealing temperature and holding time, on the relief of residual stress in welded plates with various thicknesses. A sequentially coupled thermal–mechanical finite element model was used to calculate the residual stress distribution in welded AH36 steel plates before and after PWHT. The model was validated by comparing its predictions with the experimental measurements, and the results showed good agreement. The residual stress of the thick welded plates was effectively reduced via PWHT with local induction. The primary mechanism for this stress release was identified as stress relaxation caused by creep strain. Furthermore, a process map was established considering the PWHT conditions and plate geometry. This map provides a means of determining the optimal PWHT conditions to achieve desired stress reduction levels.

Experiments On Gasketed Plate Heat Exchangers with Segmented Corrugation Pattern

Abstract Gasket plate heat exchanger (GPHE) is among the most used heat exchanger types, known for its high effectiveness and compact design. Its remarkable feature is the corrugated plate geometry, typically a Chevron pattern. This work aims to analyze another corrugation pattern, which has segments with different angles to the vertical. The strengths and weaknesses of the segmented plate are still unclear, as the studies on this pattern are scarce. To fill this gap, we experimentally assess the pressure drop and heat transfer in a GPHE composed of 31 segmented plates. The plates have four quadrants, and the combination of low-angle and high-angle plates can form up to six channel types. Pressure and temperature data are acquired in 144 sets of experiments. In the pressure drop results, we observe a considerable discrepancy between the two streams, which leads to a discussion of a relevant phenomenon: the elastic deformation of the plates. If the inner pressure of the streams is not equal, the pressure gradient causes the plates to deform and change the channel geometry. The stream with the higher pressure has its channels expanded, while the lower pressure channels will be strangled. This phenomenon is rarely reported in the literature and strongly affects the pressure drop. Moreover, we present friction factor correlations for six channel types using flow data. Based on the generalized Lévêque analogy in the heat transfer experiments, we argue that the plates' deformation also affects the heat transfer.

Effect of the plates geometry on the performance of a cross-flow recuperator for indirect evaporative cooling systems

In recent years, Indirect Evaporative Cooling (IEC) is becoming a very interesting technology, as it can guarantee a good cooling effectiveness with low energy demand, thus helping to face the issues of climate change. In this work, a Computational Fluid Dynamics (CFD) model has been used to evaluate the effects of the plates geometry on the performance of a recuperator for IEC systems with dry primary and secondary channels. The model was validated against experimental data for a cross-flow IEC system with dimpled plates, and the validation results were quite satisfactory. Therefore, five types of dimpled plates differing from the original one in shape and size of the dimples were investigated. The results showed that a good trade-off between the improvement of dry-bulb effectiveness and restrained pressure losses along the channels is obtained with dimples in the shape of right prisms with either triangular, or pentagonal, or circular base section, depending on the application.

Failure investigation of fractured crane crawler track plate

A repetitive failure of crawler track plate made of G22NiMoCr5-6 of heavy-duty crane is observed to be occurring with an average rate of one track plate fractured every 100 working hours, presenting a great problem that may impose hazard on personnel and raising direct and indirect costs required for maintenance, spare parts, and downtime costs. The objective of this research is to investigate the cause of track plate failure. An experimental investigation is carried out including chemical composition, tensile test, impact toughness, hardness test, and metallographic observation along with fractography analysis. Also, working stresses are defined by applying the finite element method. Based on the results of the experimental and computational analysis, the fracture of track plate made of G22NiMoCr5-6 predominantly resulted from deficiency in the track plate geometry design which increases stress concentration within the fracture region, in addition, slight deviation of material properties compared to those prescribed by the standard may have played a role in exacerbating the problem.

Buckling optimization of variable-stiffness composite plates with two circular holes using discrete Ritz method and potential flow

Potential flow around two equal-radius cylinders is derived analytically and applied to generate the curvilinear fiber path of variable-stiffness composite (VSC) plates with two circular holes. As complex variable theory and conformal mapping are used to generate the potential flow around two equal-radius cylinders, the location and size of the two equal-radius circular holes are arbitrary. By changing the angle of incoming flow, the global fiber angle of a variable-stiffness lamina can be simulated and the local fiber orientation angle at any point is determined by the global potential flow field. Buckling performance of variously-shaped VSC plates with two circular holes are investigated via a novel numerical method − discrete Ritz method (DRM). DRM combines the extended interval integral, Gauss quadrature, and variable stiffness within a rectangular domain and builds a discrete energy system to simulate the plate, which allows the geometric boundaries of the plate to vary. The strain energy of a plate is modeled in the rectangular domain, discretized using Gauss points, and is characterized by variable stiffness, which characterizes both the material distribution and plate geometry simultaneously. After that, a three-dimensional sampling optimization (3DSO) method is adopted to optimize the curvilinear fiber configurations of VSC plates, and its buckling performances are compared with those of constant stiffness composites (CSC) with optimal straight fibers. Significant improvements on load-carrying capacity can be achieved compared to straight ones, demonstrating that using potential flow is one of the most efficient way to generate curvilinear optimal fiber path with maximum load-carrying capacity for VSC plates with material discontinuity. Moreover, DRM exhibits good precision and stability for buckling analysis of VSC plates with complex geometries.

Elasto-inertial instability in torsional flows of shear-thinning viscoelastic fluids

It is well known that inertia-free shearing flows of a viscoelastic fluid with curved streamlines, such as the torsional flow between a rotating cone and plate or the flow in a Taylor–Couette geometry, can become unstable to a three-dimensional time-dependent instability at conditions exceeding a critical Weissenberg ( $Wi$ ) number. However, the combined effects of fluid elasticity, shear thinning and finite inertia (as quantified by the Reynolds number $Re$ ) on the onset of elasto-inertial instabilities are not fully understood. Using a set of cone–plate geometries, we experimentally explore the entire $Wi$ – $Re$ phase space for a series of nonlinear viscoelastic fluids (with the dependence on shear rate $\dot{\gamma}$ quantified using a shear-thinning parameter $\beta _P(\dot {\gamma })$ ). We tune $\beta _P(\dot {\gamma })$ by varying the dissolved polymer concentration in solution. This progressively reduces shear thinning but leads to finite inertial effects before the onset of elastic instability, and thus naturally results in elasto-inertial coupling. Time-resolved rheometric measurements and flow visualization experiments allow us to investigate the effects of flow geometry, and document the combined effects of varying $Wi, Re$ and $\beta _P(\dot {\gamma })$ on the emergence of secondary motions at the onset of instability. The resulting critical state diagram quantitatively depicts the competition between the stabilizing effects of shear thinning and the destabilizing effects of inertia. We extend the curved streamline instability criterion of Pakdel & McKinley (Phys. Rev. Lett., vol. 77, no. 12, 1996, p. 2459) for the onset of purely elastic instability in curvilinear geometries by using scaling arguments to incorporate shear thinning and finite inertial effects. The augmented condition facilitates predictions of the onset of instability over a broader range of flow conditions, and thus bridges the gap between purely elastic and elasto-inertial curved streamline instabilities.