Plate Thickness Research Articles

Study on the mechanical properties and microstructures of Al-Cu-Mg alloy thick plates obtained by different hot rolling processes

Abstract In the research, the microstructures of large-scale 2324 aluminum alloy thick plates obtained through two different hot rolling processes are investigated by using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and Electron Backscatter Diffraction (EBSD). Additionally, the tensile properties of the plates are evaluated at room temperature. The results indicate that the thick plates produced by Process A exhibit higher tensile and yield strengths along the L (longitudinal) and LT (long transverse) directions. The higher proportion of deformed microstructures is an important factor contributing to their enhanced tensile and yield strengths. Meanwhile, the different rolling processes have minimal impact on the kind and distribution of the second phase in the hot-rolled thick plates, with the second phase primarily consisting of Al2Cu and Al2CuMg phases, which are distributed in a streamlined way along the rolling direction of the thick plates. The microstructures of the hot-rolled thick plates obtained from both hot-rolling processes are dominated by deformed structures. The thick plates produced by Process B have relatively smaller grain sizes and a higher degree of fragmentation, making their microstructure more susceptible to recrystallization transformation during subsequent solution heat treatment.

An Approach to Calculate Source Locations for Thicker Plates when Acoustic Emission Signals are Dominated by Trailing Waves

In many acoustic emission (AE) applications, signal arrival times from an array of sensors are coupled with an appropriate velocity to calculate the source location of AE events. To date, the AE signals present in these applications are Lamb and/or Rayleigh waves. In a previous publication [1], finite element modeled (FEM) AE signals in thicker plates were dominated by trailing wave (TW) packets, when no Rayleigh wave was present. The typical character of the TW dominated signals was described as a spaced-in-time train of short-in-time wave packets. Further, it was pointed out, that when TW dominate the signals, it is not clear how arrival times for source location calculations might be obtained along with an appropriate propagation velocity. The goal of this work is to develop a source location approach for cases of dominant TWs in the AE signals in thicker plates. The FEM-signal database from the previous publication was used for this study. The database consisted of in-plane dipole sources at five different depths and four different steel plate thicknesses (50, 75, 100 and 125 mm). Bottom-surface out-of-plane displacement signals versus time for propagation distances from 250 to 1500 mm were examined. The FEM signals were frequency filtered to examine a broadband case of 80 to 500 kHz and a narrowband case of 100 to 300 kHz. To study the potential source location accuracy, a total of seven four-sensor arrays were employed. The study results describe a process to select appropriate arrival times and obtain a propagation “velocity.” This information was used to calculate source locations for the sensor arrays. The location errors were shown to be less than the plate thickness.

Air blast resistance of ARMOX 500T Steel plates with standard thickness: Experimental and numerical consideration

The numerical and experimental examinations in the behavior of ARMOX 500 T steel plates of a standard thickness under blast loading are presented in this study. Furthermore, the dynamic reaction of the steel plate is crucial, particularly when subjected to blast loads produced by various explosive forms and at a certain stand-off distance (SoD). This study conducted experimental and numerical simulation tests on steel plates under the close-range air blast loads generated by 150 g TNT cylindrical explosives, which are the most widely used explosives in the military and engineering fields. In order to investigate the failure modes of steel plates, close-range air blast load experiments were conducted at a 400 mm SoD. Pressure gauges were positioned at equal distances, and the impact of these tests on the failure deformation and dynamic response of the steel plate was quantitatively examined. Ultimately, the properties of shock waves produced by cylindrical explosives were examined in order to ascertain how SoD and charge quantity affected the shock waves' spatial dispersion.

A four-node inverse curved shell element coupling MITC method for deformation reconstruction of plate and shell structures

In the field of structural deformation monitoring, the inverse finite element method (iFEM) has significant engineering value as a structural health monitoring technique that provides timely and reliable warnings for shell structures. However, existing inverse finite elements are mainly based on first-order shear deformation theory and kirchhoff-love theory, which are not suitable for deformation reconstruction in plate and shell structures of arbitrary thickness. This study integrates iFEM with the Mixed Interpolation of Tensorial Components (MITC) method to develop a novel four-node quadrilateral inverse curved shell element, named iMICS(inverse Mixed Interpolation Curved Shell)4, aimed at enhancing the accuracy and efficiency of deformation reconstruction in complex plate and shell structures. The method uses the MITC4 shell element as the kinematic framework and applies the least squares variational principle to achieve deformation reconstruction, effectively alleviating shear and membrane locking issues across structures of varying thickness. Numerical examples validate the superior performance of the iMICS4 element, demonstrating its promising application prospects.

Effects of heat input on microstructures and mechanical properties of LAZ931 magnesium-lithium alloy in High-Speed TIG welding

LAZ931 magnesium-lithium (Mg-Li) alloy is a novel ultra-light alloy material. This research investigates the Tungsten Inert Gas (TIG) welding process of a 2.15 mm thick LAZ931 magnesium-lithium alloy thin plate without wire filling. The objectives are to determine the appropriate heat input range, achieve welded joints with good forming quality, and examine the effect of heat input on the microstructure and mechanical properties of the welded joints. The results show that post-TIG welding at high welding speed, the melt width of the entire welded joints is very narrow only about 9 mm, and a small amount of MgLiAl2 (θ) phase and AlLi (γ) phase precipitate in the weld seam zone(WSZ), while a significant amount of θ phase precipitates in the heat-affected zone (HAZ), making the HAZ the highest in strength due to precipitation strengthening. With increasing heat input, the quantity of θ phase decreases, resulting in reduced strength and hardness but increased plasticity in the HAZ. The highest hardness in the HAZ was measured at 87.6 HV, with the base material (BM) exhibiting the lowest hardness. The tensile strength of the joint reaches 163.2 MPa, with an elongation of 23.9 %, and the fracture mode is a mixed ductile–brittle fracture.

Porous acoustic metamaterial for simultaneous control of high and low frequency machinery noise: Case study of a water pump.

An acoustic metamaterial (AMM) consisting of a porous material (melamine foam) layer above a symmetrical labyrinthine metamaterial, incorporating a micro-hole and micro-slit cover plate, is proposed to simultaneously mitigate low and high frequency noise from industrial machineries. Theoretical model of sound absorption by this AMM is developed and validated numerically and experimentally. Sensitivity analysis indicates that increasing the length of the labyrinthine pathway and cover plate thickness and decreasing the slit width, slit length, and hole diameter shifts the peak sound absorption to lower frequencies. This material is successfully applied as a sound absorptive enclosure of a 0.5 hp water pump to reduce its sound pressure levels across widely separated frequencies of 1414-2245 Hz (high frequency) and 176-222 Hz (low frequency). This study offers guidelines to noise control engineers for controlling low and high frequency noise in industrial machineries.

Analysis of Saturated Impulse for Square Plates under Flat Slamming Impact: Experimental and Numerical Investigation

The saturated impulse is a special phenomenon in the dynamic plastic behavior of engineering structures under intensive pulse loading, such as slamming loading. In this study, slamming experiments were performed on steel plates to investigate their slamming pressure and dynamic plastic responses, as well as the saturation phenomenon, and elucidate the effect of the plate thickness and material properties on the dimensionless saturated deflection and saturated impulse in combination with the published test data. The results show that the dimensionless saturated deflection and saturated impulse of the test plates gradually increased as the dimensionless stiffness decreased. After being validated against the experimental results, a numerical method that considered the fluid–structure interaction (FSI) effect was then employed to provide comprehensive insight into the transient plastic responses and saturated impulse of the flat plates under slamming impact. Numerical simulations revealed that the compressed air layer always existed during the effective process of the flat slamming impact. Through the numerical prediction of the dynamic plastic deflection and slamming pulse loading, it was observed that the saturated impulse phenomenon always took place after the time instant of the peak value of the pressure pulse. Furthermore, the analysis of the saturated impulse based on the numerical simulations indicated that the saturation phenomenon was more likely to be achieved as the water impact velocity increased.

Analysis of factors affecting bone volume changes after immediate implantation in the maxillary central incisor.

This study aimed to evaluate the clinical outcomes of immediate implantation of single maxillary central incisor and explore factors affecting post-implant bone volume. Clinical data and imaging records from pre-surgery, the day of surgery, and 6 months post-surgery of 100 patients (100 implants) with non-salvageable maxillary central incisors who underwent immediate implantation were collected. Bone thickness at the cervical, middle, and apical regions of the implant's labial and palatal sides were measured immediately post-surgery and at 6 months, and bone volume changes were observed. A regression analysis model was used to assess predictive factors for labial and palatal bone plate thickness. At 6 months post-surgery, the labial bone thicknesses at the cervical, middle, and apical regions were 2.35, 2.29, and 3.28 mm, respectively, and those of the palatal side were 0.00, 2.40, and 6.05 mm, respectively. The cervical region had the highest alveolar crest collapse rates, with 32.87% on the labial side and 62.20% on the palatal side. The regression model indicated that factors influencing the thickness of bone at the cervical labial side of the implant included initial bone thickness, the implant center to adjacent tooth center angle, implant diameter, and the type of implant closure (P<0.05). The initial bone thickness on the palatal side was the sole predictor for bone thickness on the palatal side (P<0.05). Immediate implantation of single maxillary central incisors yields effective clinical results. The thickness of new bone around the implant is influenced by multiple factors. A comprehensive consideration of these factors in the planning of immediate implantation is necessary to achieve optimal therapeutic outcomes.

Corrosion-induced thickness diminution of an ageing bulk carrier

The 2030 Agenda for Sustainable Development introduced 17 Sustainable Development Goals (SDGs). The International Maritime Organization (IMO) has endorsed connections between the maritime sector and SDGs, emphasising sustainable production in the marine environment. Consequently, technical considerations, such as ship structure sustainability, are crucial for marine safety. The impact of corrosion influences the structural degradation of vessels and the risk of structural failure and fuel oil spills significantly. The formulation of predictive corrosion models, grounded in historical data accumulated during vessel operations, emerges as an optimal strategy for designing structural elements and guaranteeing their structural integrity. This paper analyses non-linear deterministic and stochastic corrosion models, focusing on an ageing bulk carrier, to provide design-phase information for sustainable structures. Utilising data on measured steel plate thickness over a 20-year operational period, non-linear models are employed to calculate the millimetres of thickness diminution. Assuming corrosion onset at 7, 8, and 9 years, corresponding coefficients are computed, based on the developed model. A model is also considered, in which there were no assumptions about the beginning of corrosion initiation. The corresponding annual corrosion rate was observed separately in each of the models, as a deterministic variable and as a probabilistic random variable. This approach aims to enhance the understanding of the causal relationship between corrosion processes and structural performance, contributing to the development of sustainable design practices in the maritime industry.

Molybdenum nanodots act as antioxidants for photothermal therapy osteoarthritis

Osteoarthritis (OA) manifests as the degradation of cartilage and remodeling of subchondral bone. Restoring homeostasis within the joint is imperative for alleviating OA symptoms. Current interventions primarily target singular aspects, such as anti-aging, inflammation inhibition, free radical scavenging, and regeneration of cartilage and subchondral bone. Herein, we developed molybdenum nanodots (MNDs) as bionic photothermal nanomaterials to mimic the antioxidant synthase to concurrently protected cartilage and facilitate subchondral bone regeneration. With near-infrared (NIR) irradiation, MNDs effectively eliminate reactive oxygen and nitrogen species (ROS/RNS) from OA chondrocytes, thereby reversed mitochondrial dysfunction, mitigating chondrocyte senescence, and simultaneously suppresses inflammation, hence preserving the inherent homeostasis between cartilage matrix synthesis and degradation while circumventing safety concerns. RNA sequencing of OA chondrocytes treated with MNDs-NIR revealed the reinstatement of chondrocyte functionality, activation of antioxidant enzymes, anti-aging properties, and regulation of inflammation. NIR irradiation induces thermogenesis and synergistically promotes subchondral bone regeneration via MNDs, as validated through histological assessments and microcomputed tomography (Micro-CT) scans. MNDs-NIR effectively attenuate cellular senescence and inhibit inflammation in vivo, while also remodeling mitochondrial dynamics by upregulating fusion proteins and inhibiting fission proteins, thereby regulating the oxidative stress microenvironment. Additionally, MNDs-NIR exhibited remarkable therapeutic effects in alleviating articular cartilage degeneration in an OA mouse model, evidenced by a 1.67-fold reduction in subchondral bone plate thickness, an 88.57% decrease in OARSI score, a 5.52-fold reduction in MMP13 expression, and a 6.80-fold increase in Col II expression. This novel disease-modifying approach for OA utilizing MNDs-NIR offers insight and a paradigm for improving mitochondrial dysfunction by regulating the accumulation of mitochondrial ROS and ultimately alleviating cellular senescence. Moreover, the dual-pronged therapeutic approach of MNDs-NIR, which addresses both cartilage erosion and subchondral bone lesions in OA, represents a highly promising strategy for managing OA.

Simulation of thermal stress predictions for NiTi coating on a stainless-steel substrate using thermal plasma spraying

Thermal stresses arise during the thermal plasma spraying of composite coatings, influenced by the differing thermophysical properties of the substrate and coating materials. This study focuses on a thick coating with a top NiTi layer and a base stainless steel (AISI 304) substrate, along with an epoxy carrier layer. Initially, the substrate is stress-free at the deposition temperature of 1400 °C. Once the coating is applied, the carrier layer activates at 150°C, introducing thermal stresses before cooling to room temperature (20 °C). Using COMSOL Multiphysics, we examine stress distribution within the assembly at both 150 °C and room temperature. The model treats the thick plate as a two-dimensional solid, with layers assumed to be isotropic and linear elastic. The higher coefficient of thermal expansion in the substrate (17.3 × 10⁻⁶) compared to the coating (11 × 10⁻⁶) results in tensile stresses in the substrate and compressive stresses in the coating.

Optimizing steel plate shear wall performance: influence of infill plate thickness and connection length to vertical boundary elements

The Steel Plate Shear Wall (SPSW) is widely used as a lateral force resisting system in areas prone to high seismic activity. This is because of its exceptional ductility and ability to dissipate energy. Previous studies have indicated that disconnecting the infill plate from the Vertical Boundary Element (VBE) can decrease the demands on the column. The observed outcomes lead to a decline in both the energy dissipation capability and the lateral load-bearing capacity. The primary goal of this investigation is to mitigate stress on the column while concurrently reducing both the energy dissipation and lateral force capacities. To accomplish this, a partial connection will be established between the infill plate and the Vertical Boundary Element. Thus, the overarching objective of this research is to identify the optimal connection length that minimizes the demands on the column while simultaneously curtailing the reduction in energy dissipation and lateral force capacities. Using Abaqus software, twenty models with different infill plate thicknesses and lengths of connection between the infill plate and Vertical Boundary Element were analysed. To determine the optimal length of connection between the infill plate and Vertical Boundary Element, the energy dissipation capacity, lateral load capacity, and column stresses were evaluated and compared. The maximum dissipation of energy occurs at a connection length of 75% between the infill plate and Vertical Boundary Element and an infill plate thickness of 12 mm. In contrast, the greatest lateral load capacity is achieved at connection lengths of 50% between a 25 mm infill plate thickness and a Vertical Boundary Element weight of 25%. The column stress reaches its minimum value when the infill plate measures 20 and 25 mm, and it reaches its maximum value when the infill plate measures 6 mm and 12 mm. By increasing the thickness of the infill plate and minimizing its connection to the Vertical Boundary Elements, the column stress in Vertical Boundary Elements can be decreased, while simultaneously enhancing lateral load capacity and maintaining an adequate level of energy dissipation.

Calculation Thickness of the Added Flexural Layer on Composite Layer using a Light Weight Deflectometer (LWD) Pusjatan

Calculating the thickness of the flexible overlay needs to consider several factors, such as traffic load, soil characteristics, existing pavement conditions, and planned changes to the road design. This procedure generally uses recognized pavement design methods, such as the AASHTO 1993 method (Guide for Design of Pavement Structures). This research aims to determine the thickness of the added layer using an asphalt layer on composite roads in accordance with the 1993 AASHTO standards. It is hoped that this method can produce an effective overlay design, extend the life of the pavement, and increase the comfort and safety of road users. The data used in this research includes primary and secondary data. The results of this analysis are to calculate the STA 0 segment, for other STAs use the same method. From the Light Weight Deflectometer (LWD) deflection data, the Subgrade Reaction Modulus (k) value was 473 psi/in, the Concrete Elasticity Modulus (Ec) value was 4,843,105 psi and the Rupture Modulus (Sc') value was 699 psi. The traffic load used is 25.000.000, so the result of calculating the plate thickness to serve future traffic (Df) is 10.79 inches or 27.40 cm and the effective plate thickness value (Deff) is 9.13 inches or 23.30 cm, then the result is the added layer thickness (Dol) is 3.30 inches or 8.39 cm

Study on the deformation and failure laws of surrounding rock under reduced roof thickness in Salt Cavern Gas Storage

Under the premise of guaranteeing the stability of the gas storage reservoir, reducing the thickness of the salt layer on the top plate of the gas storage reservoir can improve the utilization rate of the salt layer in the construction section and increase the vertical height of the gas storage reservoir cavity, creating a larger gas storage space. The mechanical planar model of the casing-cement sheath-surrounding rock in the top plate of the salt cavern gas storage reservoir yields the elastic–plastic theoretical solution for the stress and deformation of the well wall surrounding rock. Based on this, a three-dimensional mechanical numerical model of the top plate is constructed to compare the effects of various top plate thicknesses on the surrounding rocks of the gas storage reservoir and to analyze the stress and deformation behavior of the wall surrounding the rock of the top plate of the reservoir in the cementing section and bare wells under the long-term injection and extraction cycle. The results indicate that reducing the thickness of the roof salt layer primarily affects vertical displacement, radial displacement, equivalent strain, and principal stress changes in the cement sheath and surrounding rock. All other roof parameters, except for equivalent strain, show an increasing trend. Reducing the salt layer thickness in the cementing section has the least impact on the gas storage roof’s stability. In contrast, reducing the salt layer thickness in the cementing section and bare wells has a moderate impact, while reducing the thickness solely in the bare wells is the most detrimental. These findings provide valuable insights for optimizing the roof thickness of gas storage facilities and enhancing the utilization of the limited salt layer in the reservoir section.

Prediction of dK/da effects on stress corrosion crack growth rate of irradiated stainless steels based on slip oxidation mechanism

This study developed a predicting method for the crack growth rate (CGR) of stress corrosion cracking (SCC) under varying stress intensity factor (K) conditions for irradiated stainless steel (SS). First, optimization of the Hashimoto-Koshiishi model equation for calculating CGR under varying dK/da conditions was carried out using the Rice, Dugan, and Sham (RDS) equation for the crack tip strain rate. Second, the model input coefficients were set to incorporate the effect of dK/da on SCC CGR to fit the experimental data. Finally, the effect of dK/da on the CGR for 3 dpa irradiated SS of a core shroud was evaluated taking into account the weld residual stress distribution. The model prediction showed that there was little effect on the CGR for the increasing and decreasing K regions in the plate thickness direction of the core shroud under boiling water reactor (BWR) normal water chemistry, but the effect was not negligible for the decreasing K region under BWR hydrogen water chemistry.

Food Production in Ergonomically Designed Unit with Low Energy Consuming Thick Film Hot Plate

The Trans-Himalayan region of Ladakh is a cold desert where the temperature drops as low as -45°C, which makes the cultivation of fresh food almost impossible. The region is strategically very important as it borders two countries China and Pakistan. The unavailability of fresh food causes nutritional deficiency in the deployed troops and locals, affecting their performance. Cultivation of fresh food is very difficult due to the average low temperature and mountainous soil of the region. Transportation of fresh food to such forward locations causes decaying of nutrition besides the difficulty of reaching such snow-bound mountainous locations. Nutritious micro-greens grown in media under controlled conditions look perfect solutions for meeting nutritional requirements. The present study focuses on year-round cultivation of nutritious micro-green (2-3 times more nutritious than mature counterparts) with low energy consuming thick-film hot plate for necessary temperature maintenance in properly designed portable structures to reduce dependency on packaged food which are the causes of many diseases. The study involves the development of a thick film energy-efficient micro-climate maintenance technology-based system for the maintenance of temperature along with phase-wise development of suitable cultivation structure and standardization of the number of such plates and sizing of the portable unit.These hotplates produce heat based on the principle of Joule heating or resistive heating and the power of a hotplate is equal to I2R. The hotplates are capable of raising the surface temperature to 90°C –100°C at the expense of only 8W power consumption and maintenance of average temperature in the range of 18°C to 20°C at -25°C to -40°C outside ambient temperature. The region receives the highest solar irradiance along with annual average of 7-8 hours of sunshine duration and hence a solar-based technology can fulfill the energy supply of 8W with ease.The study revealed that a suitable temperature can be maintained for growing variety of nutritious micro-green in a triple layer-based multitier structure integrated with low energy consuming (~8 W), small (50.8 mm (x) 50.8 mm), efficient, and lightweight thick film technology.Thick-film hot plate integrated standardized unit is capable of producing an average of 1000grams/trial/unit in a short period of 8-12 days during the winter period of 6-8 months for the targeted supply of 8-10grams/person/day with total energy consumption of approximately 20-25Kw/trial at ~3350 m to ~5400 m Altitude.

Python-based numerical study on bolted joints between Fe-SMA and steel plates for structural reinforcements

In order to rehabilitate the performance of deteriorated steel structures, the active prestressed reinforcement employing new intelligent material, Iron-based shape memory alloy (Fe-SMA), has received extensive attentions. To reveal the mechanical properties of bolted joints between Fe-SMA and steel plates, a parametric method to establish finite element model via secondary development of ABAQUS based on Python scripts was proposed. It greatly reduces modelling costs and improves modeling efficiency. Besides, the proposed numerical models were verified against the experimental results by failure mode, final deformation, load-displacement characteristics, ultimate load-bearing capacity and initial stiffness. It is demonstrated that the numerical simulation results are in good agreement with the experimental results. What is more, a parametric study on thickness and geometry of steel plates, as well as the end distance, edge distance and thickness of Fe-SMA plate was conducted to verify the applicability of current leading specifications for steel structures. It is evident from the results that the thickness of Fe-SMA should be controlled to prevent failure of parent steel structures. Furthermore, similar to steel plates, the thickness of Fe-SMA plate can be considered linear and the failure of bolt can be avoided, as described in Chinese code GB 50017–2017 and Eurocode 3 Part 1–8. However, the minimum allowable edge distance in Chinese code GB 50017–2017 and the ultimate load-bearing capacity calculated by Eurocode 3 Part 1–8 is conservative for bolted joints between Fe-SMA and steel plates. Hence, it is urgent to formulate design specifications for this kind of bolted joints for the scientific and economical application of Fe-SMA in structural active reinforcements.

Enhancing charpy absorbed energy of aged duplex lightweight steel plates through TRIP and TWIP mechanisms

Ensuring toughness in thick hot-rolled plates remains a challenge for lightweight steels in automotive, shipbuilding, military, and construction industries despite improved tensile properties. This study investigated the Charpy absorbed energy of thick hot-rolled Fe-0.4C-15Mn-6Al duplex lightweight steel plates exhibiting TRIP and TWIP mechanisms, aged at 450–500 °C to precipitate κ-carbides. Fracture initiation and propagation energies measured from instrumented Charpy impact testing were analyzed through microstructural and microfracture analyses. The 500 °C-aged (A500) specimen showed the highest Charpy absorbed energy, composed of the highest fracture initiation and propagation energies across all test temperatures, particularly due to active TWIP and TRIP mechanisms along with significant κ-carbide precipitation strengthening. Despite predominantly ductile fracture modes, regardless of aging temperature and test temperature, deformation mechanisms were influenced by stacking fault energy (SFE). Aging resulted in κ-carbide precipitation, reducing C and Mn contents in austenite and lowering SFE. At 25 °C, the superior energy absorption of the A500 specimen (296 J) was attributed to its high flow stress and extensive roughness in the fracture surface due to crack deflection in the fracture initiation region and zigzag crack propagation. The Charpy absorbed energy decreased significantly at lower temperatures due to limited development of slip line field and less zigzag crack propagation. Despite this, the A500 specimen maintained the highest energy absorption due to its optimized TWIP and TRIP mechanisms and κ-carbide precipitation strengthening.

Passive control of hydro-elastic vibrations of plates using shunted piezoelectric patches

Suppressing structural vibrations is a vital engineering requirement in many applications. In this study, an analytical model is initially developed for predicting the forced vibration response of a fluid-loaded plate with arbitrary boundary conditions attached to piezoelectric patches. Each piezoelectric patch is connected to a resonant shunt circuit consisting of a resistor and an inductor. Using the analytical model, it is demonstrated that the vibration control is effective for cantilever plates immersed in water. This is demonstrated first for the vibration control at individual resonance frequencies, and then at multiple resonance frequencies simultaneously using several separate piezoelectric patches. A parametric study is then performed to investigate how the efficiency of the method varies with the plate thickness, patch thickness, and patch size. It is observed that although the vibration reduction decreases steadily with increasing plate thickness, the shunted piezoelectric patches can still effectively damp the plate vibration, and their performance can be further improved by increasing the size and/or thickness of the patches.

Experimental study on mechanical properties of pin-trunnion connection nodes of temporary steel brackets for elevated bridges

Currently, the pin connection test exists mainly for unidirectional force loading, while the pin connection of a temporary steel bracket applied to elevated bridges is for bi-directional force. The damage mechanism of the pin connection with bi-directional force is not yet fully understood in research. The effect of the loading direction, single-hole plate end distance and unilateral width ratio a/b, ear plate thickness ratio t1/2 t2, and ear plate shape on the mechanical properties of the pin connection need to be considered. In this study, destructive static loading tests were conducted on eight groups of double-hole pin connections, and the damage mode, bearing capacity, deformation, and strain of the pin connections were determined. The results show that the thickness of the trunnion plate primarily controls the damage mode of the pinned connection and the ratio is smaller for single-trunnion plate damage, which can achieve larger bearing capacity and deformation. The ratio of the end distance of the monocore plate to the width of the single side primarily controls the damage location of the monocore plate, and the ratio varies from large to small, gradually causing tensile damage to the side section, end cleavage damage, and end shear damage. The loading direction has a minor effect on the mechanical properties of the pin connection; however, the tensile deformation is significantly larger than the compressive deformation. By chamfering, the M shape is properly adjusted to optimize the shape of the double trunnion plate, which does not reduce the load-carrying capacity and deformation of the pin connection and can reduce the amount of steel used by 10 %. A comparative analysis of the change in the ear-plate shape before and after the open ear-plate test, determination of the cross-sectional damage location and effective calculation distance b1, and improvement and derivation of a practical method for calculating the load-carrying capacity for engineering are performed, at the same time, it can be applied to projects of different spans, which can greatly improve construction efficiency and reduce labor costs.