Plate Type Research Articles

Experimental and Numerical Investigation of Joints for a Pultruded Fiber-Reinforced Polymer Truss.

Bolted connections usually govern the structural rigidity and load-carrying capacity of pultruded glass fiber-reinforced polymer (GFRP) truss structures. In this study, a novel bolted integrated gusset plate (IGP) connection is proposed to enhance the stiffness and capacity of GFRP truss structures. Nine double-lap shear tests of GFRP joints and numerical simulation were conducted to investigate the influence of variable design parameters of the bolted GFRP joints (number of bolts, width and thickness of GFRP, edge distance of bolts, and the employment of adhesive). Three full-scale GFRP truss joints were tested under static loading to study the response of a typical bolted connection, a bolted gusset plate connection, and the proposed IGP connection. The nine double-lap shear tests showed that the bolted-bonded mixed connection has 50% higher shear stiffness and 27% higher ductility compared with bolted joints, and bearing failure dominated the capacity of most specimens, which agreed well with numerical simulation results. Tests on the three full-scale GFRP truss joints showed that the bolted gusset plate can substantially reduce the number of cracks and improve the initial stiffness, but the maximum bearing capacity of the joints did not increase because the shear fracture of pultruded GFRP webs governs the capacity. The proposed IGP substantially increased the stiffness and capacity compared with the bolted connection and typical bolted gusset plate connection. The full-scale GFRP joint test is suggested to be used together with direct shear tests to study the performance of joints of the GFRP truss.

Design and construction of a gas filter system for hospital incinerators

An incinerator is designed to burn combustible waste materials such as municipal solid waste and infectious waste into inert ash. The design reduces waste volumes and subsequently destroys pathogens. A gas filtering unit is designed, constructed, and fitted on an existing incinerator for cleaning the smoke from medical waste treatment. Its main components are a framework whose material is made of galvanized diamond, three wire meshes, made of steel, to serve as filter bed supports, an inlet and 2 sampling holes of diameter 1.5cm beneath the wire meshes, and an outlet and 2 sampling holes of 1.5 cm above the wire meshes. As part of the gas filter design considerations, the amounts of dry volumetric gas discharged during combustion, and of particulate matter produced per cycle of combustion in the chosen incinerator were estimated to be 12,051.86 m3 /cycle, and 2.17 kg PM/cycle of incineration respectively. The novelty in this design consisted in adapting the impingement plate type of wet scrubbing unit for dry adsorption of organic pollutants in smoke using locally-activated charcoal powder. The incorporation of powdered activated charcoal in the filter unit as adsorbent material significantly reduces the emission of harmful pollutants into the atmosphere. As a result, pollution of the environment is minimized. The smoke was sampled before and after filtration, and the samples were later tested in the laboratory for 14 polychlorinated biphenyls, namely PCB 18, PCB 28, PCB 31, PCB 44, PCB 52, PCB 101, PCB 118, PCB 138, PCB 149, PCB 153, PCB 170, PCB 180, PCB 194 and PCB 209. The three charcoal filter beds used in the evaluation study achieved target pollutant reductions in smoke ranging from 2.03 % - 71.85%. An Air Pollution Control Device with such pollutant reductions should justify the continued use of incinerators if they are properly mounted and secured on the incinerators and can curb the problem of air pollution from point sources.

Vibrational Characteristics of a Foam-Filled Short Basalt Fiber Reinforced Epoxy Resin Composite Beetle Elytron Plate.

The vibrational properties and mechanism of a foam-filling short basalt fiber reinforced epoxy resin composite beetle elytron plate (EBEPfc) were studied by experiments and the finite element (FE) method in this paper. The experimental results showed that the natural frequencies of the first two modes of the EBEPfc were very close to those of a foam-filling short basalt fiber reinforced epoxy resin composite honeycomb plate (HPfc), while the vibrational response of the EBEPfc was weaker than that of the HPfc, and the damping ratio was improved; the improvement of the second mode was significant. Therefore, the EBEPfc had a better vibration reduction performance and could directly replace the HPfc in engineering applications. The FE results showed that foam filling enhanced the shear stiffness of the whole core structure, and had a more obvious effect on the shear stiffness of the HPfc. Meanwhile, it particularly reduced the shear force proportions and contributed to the protection of the skin and core skeleton. The mechanisms of the vibrational characteristics of these two types of sandwich plates were explored from the perspective of the equivalent cross-sectional area, shear stiffness, shear strain energy per unit volume and friction. These results provide a valuable reference for the promotion and application of EBEPfc in the fields of vibration reduction and seismic resistance.

Localization of Vibration Weak Position of Composites Based on Weighted Modal Strain Energy Summation

In this paper, two typical examples are used to illustrate the weak position of aircraft structure in the process of vibration. Through the modal analysis of the typical composite plate and I-shaped beam, the first 20-order modal strain energy of the plate is extracted, which is difficult to locate the weak spot due to the highly scattered location of the higher modal strain energy. The modal participation factor is introduced as the weight factor of the summation of the modal strain energy. The modal participation factor is large, the weighting factor is large, and the high modal strain energy of the composite plate moves diagonally in the 45° direction of the composite plate and the high strain energy region is consistent with the previous modes of the plate. This is the result of the weak in-plane shear stiffness of the composite panel, which shows the effectiveness of the mode weighted summation method. The I-shaped composite beam uses the modal strain energy summation of the weight factor, and the higher modal strain energy is concentrated on the middle part of the beam and at 1/4 and 3/4 of it. Therefore, the weak part of the vibration can be clearly identified. The higher modal strain energy is extracted by the method proposed to this paper, which can be used as a reference to structural design and dynamic on-line monitoring.

UAV with Vision to Recognise Vehicle Number Plates

The trend of using Unmanned Aerial Vehicles (UAVs) in industries is rapidly growing. Nowadays, they are used in many applications, from surveillance to disaster assistance. Almost all applications of UAVs require cameras either to perform specific vision tasks such as facial recognition and vehicle number plate identification or to avoid obstacles in the flight path of the UAV. The most emerging application of UAVs today is to provide security and surveillance, and they are mostly used for vehicle number identification. Typical Automatic Number Plate Recognition (ANPR) uses static high-resolution cameras mounted in specific places to identify the vehicle’s number plates. Identifying the characters on the number plate becomes a very crucial task when the number plate is at an arbitrary angle to the drone camera. The camera gimble angle, the height of the UAV from the vehicle, and the relative speed of the UAV w.r.t vehicle play a very key role in identifying the vehicle license plate correctly. This study explains how Automatic Number Plate Recognition (ANPR) is performed on real-time images using MATLAB with the help of a UAV to analyze the effect of the above-mentioned key factors. The process is completed in three steps: collecting visual data from the drone, processing that data, and obtaining the recognized number plate.

Effects of perforated plate on hydrogen flow in L-shaped high pressure reducing valve

Pressure reducing devices are the most vital component of the on-board hydrogen supply system. A good pressure reducing system design helps to achieve long-distance and efficient driving of the hydrogen fuel cell electric vehicle. In this study, a newly L-shaped high pressure reducing valve is proposed for hydrogen decompression. Perforated plate is the most vital throttling component. However, the effects of the perforated plate on hydrogen flow in L-HPRV is not clear now. Therefore, the effects of typical perforated plate parameters as shape, row (n), orifice diameter (d), chamfer radius (r) and pressure ratio (Pi/P1) on the L-HPRV fluid dynamics are investigated. Furthermore, based on the parametric sensitivity analysis, the optimized design of the L-HPRV is achieved. Results show that the L-HPRV is well-designed for hydrogen decompression. The circle, rhombus shaped perforated plate, and the larger diameter help achieve better fluid dynamics during the hydrogen decompression process. The perforated plate numbers have a reduction effect on both the pressure and velocity gradients, while the perforated plate pressure ratio has a proportional effect. This study reveals the perforated plate effects on hydrogen flow for the first time, and provides technological support for experts to achieve throttling design of related control valves in hydrogen industry.

Compression and tension tests of wooden elements with glued steel plates

The use of classical elements in spatial structures of prefabricated buildings is inefficient due to a design complexity and specific quantity of metal in the assembled components. The paper studies the durability, stability and deformability of wooden elements with glued metal plates working in a multiply connected structure under compressive and tensile loads. The experiment series include maximum loads causing the loss of stability and destruction of prototypes as well as deformation of wooden and metal elements. As a result, the dependences are suggested for the carrying capacity of elements on the load type, thickness and depth of the glued steel plate, and the dependence of tension and compression of elements on the efforts. The latter can be applied in calculations under the strain scheme and modeling of the joint compliance of the multiply connected structure.

The Prediction and Correction Method of Aircraft Static Aeroelastic Effects: A Review of Recent Progress

This paper comprehensively reviews the progress of static aeroelastic effect prediction and correction methods for aircraft, including the damage and protection of aeroelastic. It is significantly important to determine the similarity conditions and static aeroelastic scaling modeling in wind tunnel experiments to obtain accurate aerodynamic characteristics. Meanwhile, similar stiffness distribution, manufacturing materials, and processing technology are strongly associated with the simulation of aircraft structural dynamics. The structural layout of the static aeroelastic model, including plate type, beam type, bearing skin type, and full structural similarity type, are described in detail. Furthermore, the wind tunnel and test technique also play an important role in static aeroelastic experiments. It is worth noting that computational fluid dynamics (CFD) and computational structure dynamics (CSD) have attracted increasing attention from researchers for application in aeroelastic analysis of the flow field. The research status and key technologies of aeroelastic numerical simulation of aircraft are introduced in detail. Additionally, this paper briefly introduces the static aeroelastic prediction and correction method, especially the widely practiced K-value method.

Processing performance of vitrified bonded fixed-abrasive lapping plates for sapphire wafers

To enhance the lapping effects of sapphire wafers, two vitrified bonded fixed-abrasive lapping plates with different mechanical properties were developed and used to lap sapphire wafers to evaluate the effects of lapping time and dressing cycle on the lapping process effect and the stability of the lapping plates. The results indicate that the lapping material removal rate (MRR) and surface roughness (Ra) of the workpiece decrease with increasing lapping time; the higher the hardness of the lapping plate, the larger the MRR and Ra. There are differences in the primary wear forms between the two types of plates, with the high-hardness plate being mainly abrasive wear and abrasive breakage, while the low-hardness plate being mainly abrasive peeling off and abrasive wear. The two plates have the same trend in material removal for sapphire wafers - increasing the lapping time, the MRR is found to be gradually decreased and plateaued after 30 min, which is only about 20% of that of the initial lapping time, resulting in the plates needing to be dressed. After dressing the lapping plates, the plate processing performance returns to its initial state; the MRR deviation is less than 10% within the same period of use after several dressings.

Additional cuff suture provides mechanical advantage for fixation of split-type greater tuberosity fracture of humerus

PurposeSplit type of greater tuberosity fracture has variety of surgical treatment options. This study aimed to compare the biomechanics property of additional cuff suture and other fracture fixation techniques. MethodsFifteen porcine humeri were categorized into three groups of fixation techniques those were proximal humeral internal locking system (PHILOS) plate with 2 cuff sutures, nonlocking (conventional, 3.5 mm) T-plate with 2 cuff sutures and T-plate with washer that had additional cuff suture (novel technique). Fracture was created by greater tuberosity osteotomy with 50˚ inclination to the line of surgical neck and then fixed with different prescribed techniques. Displacement of fracture site was measured with universal testing machine. The maximum forces to produce 3 mm, 5 mm of displacement and load to failure were recorded. ResultsThe average loads to reach 3 mm, 5 mm displacement and failure were 30.8 N, 45.4 N and 161 N for nonlocking T-plate; 76.6 N, 99.2 N and 144 N for PHILOS plate; 95.8 N, 120 N and 197 N for novel technique. The differences among three groups were significant in load to displacement at 3 and 5 mm (but not significant in load to failure). For load to reach 3- and 5-mm displacement, PHILOS plate and novel technique were significantly stronger than nonlocking T-plate (P < 0.05). For load to reach 3 and 5 mm displacement, novel technique was stronger than PHILOS plate but not significant (P > 0.05). For load to failure, novel technique was stronger than nonlocking plate and PHILOS plate but not significant (P < 0.05). ConclusionThe important factors affecting the strength of fracture fixation are type of plate and numbers of suture augmentation that tie to the plate. Fixation with additional cuff suture showed the superior biomechanics of load to reach 3 mm, 5 mm displacement with better load to failure compared with PHILOS plate and conventional T-plate alone.

Genetic structure and historic demography of endangered unarmoured threespine stickleback at southern latitudes signals a potential new management approach.

Habitat loss, flood control infrastructure, and drought have left most of southern California and northern Baja California's native freshwater fish near extinction, including the endangered unarmoured threespine stickleback (Gasterosteus aculeatus williamsoni). This subspecies, an unusual morph lacking the typical lateral bony plates of the G. aculeatus complex, occurs at arid southern latitudes in the eastern Pacific Ocean and survives in only three inland locations. Managers have lacked molecular data to answer basic questions about the ancestry and genetic distinctiveness of unarmoured populations. These data could be used to prioritize conservation efforts. We sampled G. aculeatus from 36 localities and used microsatellites and whole genome data to place unarmoured populations within the broader evolutionary context of G. aculeatus across southern California/northern Baja California. We identified three genetic groups with none consisting solely of unarmoured populations. Unlike G. aculeatus at northern latitudes, where Pleistocene glaciation has produced similar historical demographic profiles across populations, we found markedly different demographics depending on sampling location, with inland unarmoured populations showing steeper population declines and lower heterozygosity compared to low armoured populations in coastal lagoons. One exception involved the only high elevation population in the region, where the demography and alleles of unarmoured fish were similar to low armoured populations near the coast, exposing one of several cases of artificial translocation. Our results suggest that the current "management-by-phenotype" approach, based on lateral plates, is incidentally protecting the most imperilled populations; however, redirecting efforts toward evolutionary units, regardless of phenotype, may more effectively preserve adaptive potential.

Effect of thickness stretching and electro-mechanical loading on sandwich FGM plate with piezoelectric face sheet with different boundary conditions: A semi-analytical approach

Functionally graded material (FGM) belongs to the class of advanced composite materials with material properties that vary according to the volume fraction. FGM is the future material for smart structures, being used in place of conventional composite materials. The article aims at performing the static analysis of different types of sandwich FGM plates with a piezoelectric face sheet taking into consideration the porosity and thickness stretching effect. The problem is formulated using a variational approach and the bending solution is obtained for the first time using Galerkin Vlasov’s method. Three different types of porous sandwich plates are considered for the analysis when subjected to sinusoidally distributed mechanical and electrical loading. For the first time, a new uneven non-symmetric porosity model is put forward to capture the realistic bending behavior of the plate. The effect of boundary conditions, thickness stretching, and applied voltage on stress and deflection distribution along and across the porous plate’s surface is analyzed. It is observed that effect of the applied potential difference when assumed to be a function of position, the change in stresses and deflection are approximately 30%. This infers that voltage distribution plays a significant role in the distribution of stresses in the plate and cannot be neglected which is otherwise assumed as a constant by various researchers. To check the exactness and validity of the current formulation, various examples are discussed. The estimated results can be used as a validation study for the upcoming research on porous sandwich FGM plates with piezoelectric facesheets. Communicated by Francesco Tornabene

Influence of the type of fastening of the slope of hydrotechnical structures on the reduction of the cost of their construction

In the field of fixing the slopes of hydraulic structures in the conditions of wave impacts, the world construction industry has accumulated considerable experience. The article considers four types of slope mounting plates: reinforced concrete slabs, gabions, concrete-filled mats and fasteners made of coarse-pored concrete (crushed stone and recycled broken concrete). The article is devoted to the feasibility study of the most common types of fastening of slopes of hydraulic structures. When performing the justification, the following fastening characteristics were taken into account: the thickness of the fastening from the condition of ensuring their stability, the boundaries of the fastening, the cost of resources for the device of one square meter of fastening. The most significant results of the study are the obtaining of technical and economic indicators of a new type of fastening plates and their comparison with other options.

On influence of face sheet distributions on low-velocity impact failure of metal honeycomb core sandwich plates

The influence of face sheet distributions on failure and energy absorption of metal sandwich plates with aluminum honeycomb core subjected to low-velocity impact is investigated experimentally and numerically. A fair comparison of three types of asymmetric sandwich plates with an equal area density is made by changing the thickness distribution of upper and lower face sheets. The low-velocity impact experiments are performed and the active failure modes are obtained. The finite element (FE) simulations are conducted and agree well with the experimental results. The energy absorption mechanism of sandwich plates is identified and explored with aid of the FE simulations. It is shown that the thickness distributions of upper and lower face sheets have significant effects on dynamic response, failure mode and energy absorption distributions of the sandwich plates.

New symplectic analytic solutions for buckling of CNT reinforced composite rectangular plates

This paper presents new analytic solutions for buckling of non-Lévy-type carbon nanotube (CNT) reinforced composite rectangular plates, including cantilever, free, and clamped ones. The buckling problems of such types of plates cannot be handled by some conventional analytic methods through expressing mechanical quantities in pre-defined solution forms, which, however, is excluded by the present analytic symplectic superposition method. The present method not only provides a more rigorous solution procedure but also enables more types of plates to be analytically solved. The governing partial differential equation is first expressed in the Hamiltonian system-based symplectic space, and then the variable separation as well as the symplectic eigen expansion are utilized to analytically solve two elementary buckling problems. By a skillful superposition of the elementary solutions, the eventual buckling solutions are obtained. Comprehensive buckling load/mode results are tabulated as new benchmarks. With the new analytic solutions, the parametric studies on CNT distributions, CNT volume fractions, aspect ratios, and boundary conditions are conducted to reveal the effects on the plate buckling performance.

Feasibility Study on the Initial Kartini Reactor Core Using Plate Type Fuel Elements

The plate type fuel element conversion is proposed to solve a supply problem of TRIGA standard rod type fresh fuel in the long term and to extend the lifetime by reducing the dependence of buying imported elements. The plate type fuel is an alternative since the Indonesian industry has been able to produce such fuel elements. The change of core configuration is expected to improve the reactor performance for irradiation facilities and fuel element lifetime. The SRAC2006 is used to perform neutronic calculations while the nuclear fuel lifetime is calculated by SWAT. This study begins with performing a core properties comparison of UZrH1.6 as the current fuel material and U3Si2-Al as the fuel material candidate. The results show that the Kartini reactor core is possible to load U3Si2-Al as the fuel material and makes higher excess reactivity compared to the current fuel material. Furthermore, U3Si2-Al in the plate type element geometry is variedly arranged in the new reactor core configuration to optimize the neutronic core parameters. The new core configuration is composed of 10 standard fuel elements, 4 fuel control elements, and the graphite material baffle that is located between the active core and annular reflector for serves as an additional reflector. The configuration produced sufficient core excess reactivity and adequate shutdown margin. It also produced negative temperature feedback reactivity and power peaking factor that fulfilled the safety requirements. Improvement of new reactor core performance was obtained by more irradiation facilities, higher thermal neutron flux, and longer maximum estimated burn up compared to the current core configuration.

Welding distortion prediction of ship plate frame structures based on a self-learning database

ABSTRACT Welding distortion will increase the shipbuilding cost. Therefore, it is important to accurately predict the welding distortion of a structure during the design stage. In this paper, a novel welding distortion prediction method for ship plate frame structures based on a self-learning database was proposed. Based on a typical plate frame structure in a shipyard, the applicability of the method was verified by comparing the prediction with on-site measurements. To solve the problem of choosing the welding sequences of structures with too many welds, the Latin hypercube sampling method was selected to arrange the weld samples in sequence. The results showed that the distortion of the structure was mainly concentrated on the upper shell. The numerical simulation coincided with the measurement results, and the accuracy was within 20%. Moreover, a reasonable welding sequence can decrease the distortion of a structure by 11.2%.

Anti-impact performance of bionic tortoiseshell-like composites

Biological stiff-soft phase composite structures, such as tortoise shells and conch shells, have excellent anti-impact performance to withstand various types of high-stress events encountered in nature. A remarkable 3D interdigitating zigzag architecture in the tortoise shell, named occlusal suture structure, makes the tortoise shell simultaneously possess high mechanical strength and toughness, which is also an ideal stiff-soft phase composite prototype to mimic. In this study, four types of bionic anti-impact composite plates that feature the hard-soft phase architecture of tortoiseshell (Bio-T), mollusk shell (Bio-M), beetle exoskeleton (Bio-B) and nacre (Bio-N) and a homogeneous structure plate (HSP) are designed, to systematically examine and compare their roles in impact energy dissipation. Through an integrated approach combining additive manufacturing and drop tower testing, the peak force, residual velocity, and energy absorption of these bionic composite plates are studied and compared. Experimental results indicate that the Bio-T composite plate has the best impact resistance, compared with the other three bionic composites. Furthermore, the influence of the ply angle and the dimension of suture structure on the impact resistance of the Bio-T composite plate is identified. The [0°/30°/0°] arrangement is able to resist higher loads before failure. The 3D Bio-T composite plate provides a significant enhancement of anti-impact performance than the 2D Bio-T composite plate. Finally, the crack propagation mode in the suture structure of the Bio-T composite plates is examined, enhancing our understanding of the underlying mechanisms during impact. Such findings may prove useful for the design of future protective apparatus for soldiers and aircrafts, with improved anti-impact performance.

Numerical investigation on seismic resilient steel beam-to-column connections with replaceable buckling-restrained fuses

The detailed finite element model (FEM) of a new replaceable fuse steel beam-to-column joint proposed previously, where bolted steel plates located between the beam and C-shaped shear tab flanges in the beam splicing region behave as structural fuses to dissipate energy with their buckling controlled by the surrounding flanges, was developed in this paper and subjected to cyclic loading at the beam end. The simulated results matched the test results well in terms of the hysteresis curves (and the corresponding backbone curves) and failure modes. Based on the validated FEM, subsequent parametric studies were carried out to investigate the influences of the fuse plate type and slenderness ratio, and the slip coefficient between the steel plates, on seismic performance of this joint. The parametric analysis indicated that, the joint could accommodate an ultimate story drift angle of 6% without damaging the beam or shear tab flanges by using flat-type (FP) fuse plates, which are recommended over slotted-type (SP) and double-slotted-type (DSP) fuse plates, as the latter both types developed earlier buckling than the former FP-type. Eccentric-type (EP) fuse plates are also suggested, with which the joint equipped sustained an ultimate story drift angle of at least 8%. In addition, the slenderness ratio of FP-type fuse plates is recommended to be controlled within 44 since the fuse plates with higher slenderness ratios introduced damage through buckling to the shear tab flanges at an earlier stage, while the slip coefficient presented no significant impact on the joint seismic performance.

Lunate Fracture Morphology in Kienbock's Disease-A Computed Tomography Study.

Background The pathogenesis of Kienbock's disease is poorly understood. The coronal fracture line is acknowledged as a poor prognostic marker in the disease. Other fracture types in the Kienbock's wrist have subsequently been identified. Questions/Purposes The aim is to study the fracture morphology of the lunate in a cohort of patients using computed tomography. Methods Patient images were acquired using a set protocol with four-dimensional computed tomography scanning. Images were reviewed by two orthopaedic surgeons and a consultant radiologist. Static and dynamic images were assessed and a fracture map created. The relationship of fracture type to other parameters was then analyzed. Results Twenty-three patients were included in the study, including 11 males and 12 females, with a mean age of 43 years. Total frequency of fracture lines in the cohort was coronal - 26, proximal subchondral bone plate type - 24, avulsion - 19, sagittal - 16, and distal subchondral bone plate type - 11. There were statistically significantly more proximal than distal subchondral bone plate fractures ( p = 0.03), and more coronal fractures than distal subchondral bone plate fractures ( p = 0.01). There were statistically significantly more radiolunate ligament-avulsion types ( p <0.001) than other types. The sagittal fracture line through the lunate approximated closely to the ulnar edge of the capitate and the ulnar edge of the radius. Conclusion Study on the fracture morphology in the Kienbock's wrist has improved our understanding of the disease pathogenesis. Fracture lines may correspond to loading points, intrinsic and extrinsic ligament avulsions. These fracture types may play a role in disease progression and are important to identify when considering lunate salvage surgery.