Effect Of Combined Loading Research Articles

Tectono-stratigraphic framework and evolution of the northwestern Arabian plate, Central Jordan

The northwestern Arabian plate has been long influenced by various processes, including late Precambrian crustal extension, Paleozoic rifting and ice-sheet loading/unloading, and inversion during the Late Cretaceous–Late Eocene times. It has been experiencing extension in a N-S direction since the Oligocene, N-S-trending strike-slip faulting along the Dead Sea Transform Fault accompanied by the N-S extension of its surroundings, as well as shortening from E to W since the Miocene. The primary objective of this research is to examine the tectono-stratigraphic development of the Central Jordan Region (CJR), located in the northwestern Arabian plate, by employing data from seismic surveys and well logs. The CJR hosts five significant fault systems: Feinan-Zekimat AlHasa, Salwan, Karak-Wadi Al Fayha, Dana, and Hasa faults. Despite the surface expressions of these faults highlighting the tectonic impacts during the Late Cretaceous-recent period, there is a lack of comprehensive research investigating how previous tectonics influenced their structural evolution. Seismic data and well-log integration provide a unique opportunity to fill this knowledge gap. Here we identified six major stratigraphic units: upper Precambrian, Cambrian, Ordovician, Silurian, Lower Cretaceous, and Upper Cretaceous. Using time-structure maps, we also identified several phases of fault growth, with evidence suggesting that faulting primarily occurred during the late Precambrian as part of the Najd Fault System. The reactivation of these faults can be attributed to the combined effects of the Late Ordovician ice-sheet loading and the uplift during the late Paleozoic to Early Cretaceous periods. The growth of all pre-existing faults was contemporaneous with a change in the regional stress field from the Late Cretaceous to the recent. The vertical correlation between the latest Cretaceous faulting of the CJR and the previously published topographic lineaments map suggests a tectonic control on the evolution of the surface structures.

Myocardial functions by 3D speckle tracking echocardiography in pediatric acute kidney injury patients undergoing peritoneal versus hemodialysis

BackgroundAcute kidney injury (AKI) is known to induce myocardial injury by the combined effect of volume load and uremic toxins. No study has compared to date the differential effect of peritoneal vs. hemodialysis in myocardial protection in the context of AKI. Objective3D speckle tracking Echocardiography is a new sensitive marker for detection of subclinical myocardial dysfunction. The aim of this study was to evaluate presence of myocardial dysfunction in patients undergoing acute peritoneal dialysis (PD) versus hemodialysis (HD) in cases of acute kidney injury (AKI). MethodsThis study included pediatric patients diagnosed with AKI that have undergone HD or PD. It included 50 children; 25 of them were cases that suffered from AKI compared to 25 healthy children. Each patient was subjected to 3D speckle tracking and tissue doppler echocardiography. ResultsCases with AKI showed evident systo-diastolic biventricular dysfunction. Parameters of LV and RV systolic functions were more impaired in HD group compared to PD group: LV GLS (HD: 13 ± 1, PD: 15 ± 1) and RV GLS (HD: 12 ± 1, PD: 16 ± 2) respectively, LV E/E' (ratio of the peak early mitral inflow velocity to the average of peak early mitral annular and basal septal diastolic velocities) (HD:13 ± 1, PD: 9 ± 1) and RV E/E' (ratio of peak early tricuspid inflow velocity to the peak early tricuspid annular diastolic velocity) (13 ± 1, PD: 9 ± 0.9). LV and RV diastolic dysfunction were more pronounced in HD group compared to PD group. Multivariate analysis showed that the best predictor of LV systolic dysfunction was the mode of dialysis, with a P value of 0.04. ConclusionHemodialysis modality in AKI seems to be less protective to the myocardium than Peritoneal dialysis. This might be attributed to rapid reduction in fluid load, which is reported to damage endothelial glycocalyx, thereby causing myocardial edema.

Study on explosion in different cross-sectional shape charge cavity in tensile stress field

Purpose. To study nature and patterns of main cracks development in a solid medium during an explosion of explosive charge in charge cavity with longitudinal symmetrical incision and various cross-sectional shapes Methodology. Experimental methods were used to study process dynamics, nature and direction of cracks development during the explosion of explosive charge of various shapes and their transformation into a clear optical image under the influence of a focused laser beam through an optical system – the method of caustics. Study on stress field changes under the combined effect of static and dynamic loading on fracture medium by polarisation-optical method. Based on correlation analysis methods, study results are analysed. Findings. It is experimentally proved that changing angle from 0 to 45° between longitudinal cut and plane jointly affected by tensile stresses and explosion action promotes opening of main cracks both parallel and perpendicular to cut direction. Dependences of propagation of main cracks caused by an explosion in model under different loading conditions are constructed. Calculations of stress intensity coefficients in medium under explosion and tensile stresses were performed. Originality. Improved research methodology for establishing the mechanism of explosive loading of solid media by explosion of explosive charge of different cross-sectional shapes is proposed. Physical mechanism of main cracks formation and propagation in blast cavity under action of explosive charge of different shapes under different conditions of dynamic loading is revealed. Dimensions of symmetrical longitudinal incision and spatial location of crack along direction of tensile stresses are substantiated. Also, an idea of using a directed explosion to form a protective strip in the rock mass was further developed. Practical value. The research results received can be necessary for developing new technical solutions to provide additional protective measures in the field of environmental and seismic safety of protected civil and industrial facilities during blasting operations in quarries and mines.

Experimental study on cyclic lateral response of piles in sandy sloping ground

This study aims to experimentally investigate the cyclic lateral responses of piles in sloping ground. The effects of slope angle θ, number of cycles n, and loading pattern (static or dynamic) on the pile responses (inc. unloading stiffness and residual displacement) were revealed by a series of laboratory (1-g) model tests considering the combined effects of slope and cyclic lateral loading. The measured responses indicated that all the pile head displacement, bending moment, lateral earth pressure, and unloading stiffness increase non-linearly with n. Thereinto, the pile head displacement x can be fitted by the function x = A(θ)n0.1 where the coefficient A(θ) is linearly related to tanθ; the residual displacement decays exponentially with the number of cycles. In addition, the slope effect would exacerbate the pile responses under cyclic loading, for instance, the maximum bending moment is linearly related to tanθ, and the depth of contraflexure point increases by 0.14 times the pile diameter when the slope angle increases by 1°.

Dynamic performance of ultralight corrugated sandwich plate with FML face-sheets impacted by FSP-foam composite projectile

Ultralight corrugated sandwich constructions have shown great promise as multifunctional structures capable of simultaneous load-bearing, shock mitigation and ballistic resistance, yet little is known about the synergetic effects of combined shock and fragment loadings on their performance. This study presented a combined experimental and numerical investigation of corrugated-core sandwich plate with ultra-high molecular weight polyethylene (UHMWPE) fiber metal laminate (FML) face-sheets subjected to combined shock and fragment impact. The combined loading was achieved using a laboratory-based experimental technique previously proposed by the present authors, i.e., the impact of fragment-foam composite projectile fired from a light gas gun. Corrugated-core sandwich plates with both FML face-sheets and metallic face-sheets were prepared, and their ballistic/blast resistances and deformation/failure modes were characterized experimentally. Three-dimensional finite element simulations were performed and validated to provide further insight into the underlying mechanisms of dynamic responses under combined loading. Compared with the reference sandwich plate with metallic face-sheets, stacking UHMWPE composite sheets into the face-sheets not only maintained the blast-induced deflection but also improved the ballistic limit against the fragment simulation projectile (FSP). The synergetic effect of combined loading could weaken the penetration resistance and increase the permanent deflection, but the tearing cracks caused by combined loading could be significantly inhibited by the use of FML face-sheets. In addition, the impact sequence of foam and fragment affected the ballistic resistance of corrugated-core sandwich plate with FML face-sheets.

Study on Cl− Erosion of Concrete under the Combined Effect of Fatigue Load and Wet–Dry Cycles: A Review

The service environment of concrete in the marine environment is harsh, and demands regarding the durability of marine concrete have increased. Marine concrete in harbor and wharf areas suffers from the combined effect of fatigue load, dry–wet cycles, and Cl− erosion, which can result in spalling of the concrete surface, corrosion of the internal reinforcement, and even concrete damage. This paper reviews recent research results on the durability of concrete and reinforced concrete (RC) under the combined effect of fatigue load, dry–wet cycles, and Cl− erosion. We further assess the variation in Cl− transport properties with fatigue load, the causes behind the reduction in the carrying capacity of RC products under fatigue load, the methods of Cl− erosion on concrete under the pressures imposed by dry–wet cycles, and the damage of the protective layer of concrete due to accelerated Cl− erosion caused by the action of dry–wet cycles. Further studies are needed on the durability of concrete under the action of fatigue load, wet and dry cycles, and Cl− erosion, in addition to the testing of the durability of concrete under the combined effects of the afore-mentioned various factors.

Flexural stiffness of recycled aggregate concrete beams under combined effect of load and steel corrosion

AbstractSince reinforced concrete members suffer from different types of loads during their service life, the steel bars embedded in reinforced concrete members can be easily corroded in chloride‐laden environment. To investigate the influence of combined effect of load and steel corrosion on the flexural stiffness of recycled aggregate concrete (RAC) beams, 12 RAC beams were prepared and tested. The effects of load level (i.e., the ratio of the load applied to beams to the ultimate load) and recycled coarse aggregate (RCA) replacement ratio (i.e., the ratio of RCAs to replace natural coarse aggregates) on the internal force arm coefficient of cracking cross‐section, the elastoplastic resistance moment coefficient of cross‐section, and the strain incongruity coefficient of corroded tensile steel bars were analyzed, and a calculation model for flexural stiffness of RAC beams under combined effect of load and steel corrosion was established. The results showed that when the ratio of bending moment to ultimate bending moment of the pure bending part of beams was within 0.55–0.80 and the average mass loss of tensile steel bars was less than 3.23%, 0.85 could be adopted as the internal force arm coefficient of cracking cross‐section. The elastoplastic resistance moment coefficient of cross‐section was approximately a constant when the corroded RAC beams were in the service stage, while it increased obviously with the load level. There was a strong linear relationship between strain incongruity coefficient and average mass loss of tensile steel bars during the service stage of corroded RAC beams, and the strain incongruity coefficient increased linearly with the load level. The calculated values of the model of flexural stiffness proposed in this paper were in reasonable agreement with the experimental values.

Investigation of In Situ Thermal Properties and Early-Age Pavement Behavior in the Design and Performance Evaluation of Roller Compacted Concrete Pavement in Louisiana, U.S

The proven durability and high load-carrying capacity of roller compacted concrete pavement (RCCP), combined with its simple and cost-effective construction method and high placement speed, has created a great deal of interest from many states and local transportation agencies in the U.S. Roller compacted concrete (RCC) mixture uses less cement content and less water compared with conventional concrete mixtures, which reduces the total shrinkage strain and RCC set temperature during the hardening stage, resulting in a reduction of early-age deformation and stress developments in the RCCP. Currently, research on the early-age behavior and other thermal properties of RCCP has not been well documented. Therefore, investigations of early-age behavior and thermal properties such as coefficient of thermal expansion, ultimate shrinkage, and built-in curling are needed to understand the true behaviors of RCCP under real climatic conditions. On the other hand, the currently available RCC thickness design procedures, for example, Street-Pave and Pavement Designer, are in general short of flexibility in consideration of the combined effect of wheel and environmental loading on RCCP performance. The primary objective of this work is to investigate the early-age behavior of RCCP and to evaluate the effect of thermal properties on the design and performance of RCCP constructed in Louisiana.

Combined effect of seawater and load on methacrylate adhesive

Although the shipbuilding industry is constantly demanding new advanced joining solutions, adhesive technology is not as developed in the marine as compared to other industries. The main reason is the lack of specific knowledge that guarantees the durability of the bonded joints in optimal conditions during the life cycle of a ship. This work simulates in the laboratory a marine-like environment by immersing an adhesive in seawater and subjecting it to constant loading. The objective is to characterize the seawater absorption behavior and its consequences on the mechanical, thermal, and chemical properties of the adhesive after this aging process. Seawater ingress was determined through gravimetric tests at several load conditions of the tensile strength of the adhesive. Besides, absorption process was studied using Fick's Law, determining the diffusion coefficients. The thermal behavior was monitored with differential scanning calorimetry (DSC) and the chemical degradation was analyzed using Fourier transform infrared spectroscopy (FTIR). Also, the mechanical properties were determined by tensile tests. The surface of the adhesive (dried) was studied by Scanning Electron Microscopy (SEM) technique and the porosity was measured by physisorption with a high-performance adsorption analyzer. A numerical simulation was developed using Darcy's Law combined with continuity equation. The results show that application of loads and immersion in seawater until full saturation of seawater improve the mechanical properties of the adhesive, but it affects negatively to the glass transition temperature. This should be considered when designing adhesive bonding joints on ships.

Effects of heat load and hypobaric hypoxia on cognitive performance: a combined stressor approach

This study investigates how cognitive performance is affected by the combination of two stressors that are operationally relevant for helicopter pilots: heat load and hypobaric hypoxia. Fifteen participants were exposed to (1) no stressors, (2) heat load, (3) hypobaric hypoxia, and (4) combined heat load and hypobaric hypoxia. Hypobaric hypoxia (13,000 ft) was achieved in a hypobaric chamber. Heat load was induced by increasing ambient temperature to ∼28 °C. Cognitive performance was measured using two multitasks, and a vigilance task. Subjective and physiological data (oxygen saturation, heart rate, core- and skin temperature) were also collected. Mainly heat load caused cognitive performance decline. This can be explained by high subjective heat load and increased skin temperature, which takes away cognitive resources from the tasks. Only the arithmetic subtask was sensitive to hypobaric hypoxia, whereby hypobaric hypoxia caused a further performance decline in addition to the decline caused by heat load. Practitioner summary: Little is known about how multiple environmental stressors interact. This study investigates the combined effects of heat load and hypobaric hypoxia on cognitive performance. An additive effect of heat load and hypobaric hypoxia was found on a arithmetic task, which may be attributed to independent underlying mechanisms.

Nonlinear aerodynamic analysis of functional graded plates using an HSDT-based isogeometric approach

In this paper, a nonlinear FGM plate analysis model is presented based on IGA, which suppresses shear locking and is applicable to plates with a wide range of thickness-to-length ratios. Furthermore, the nonlinear aerodynamic characteristics of FGM plate subjected to the combined effect of transverse load, in-plane load, and supersonic flow are investigated. HSDT is used to construct a displacement field suitable for nonlinear vibration analysis of FGM plates with a wide range of thickness-to-length ratios. For the problem that shear locking cannot be avoided entirely in the nonlinear analysis of plates, the first derivative of transverse displacement is adopted as the first term of HSDT, which weakens the effect of shear strain. Therefore, the shear locking is effectively restrained. The nonlinear FGM plate analysis model is derived using NURBS, which meets the C1 continuity requirement of HSDT. The computational efficiency, accuracy and the suppressing capacity to shear locking are verified in three aspects: static displacement, eigenfrequency, and nonlinear frequency ratio. The Bathe method is used to obtain the displacement response of an FGM plate subjected to supersonic flow, in-plane load, and transverse load. The dynamic characteristics of the FGM plate are studied using time history, bifurcation diagrams, PSD curves, phase diagrams, and Poincaré maps.

Computational optimization of engine performance and emission responses for dual fuel CI engine powered with biogas and Co3O4 nanoparticles doped biodiesel

Given the ongoing energy crisis, rapid depletion of fossil fuel globally, and emissions generated due to its utilization, this study investigates the combined effects of Engine load (20–100%), Cobalt oxide nanoparticles doped rate (NDR, 0–100 ppm), Linseed biodiesel blend rate (BBR, 0–20%) and Biogas flow rate (BFR, 0.5–1 kg/h) on engine performance and emission outputs. Computational methods such as response surface methodology (RSM) and artificial neural network (ANN) were used to establish a prediction model based on the Design of experiment results. The developed RSM model's F-value indicates engine load as the most significant input variable in deciding the value of output responses, followed by BFR, BBR, and NDR, respectively. The statistical analysis using different evaluation metrics suggests the prediction made by the RSM model is more accurate and reliable than the ANN model. The optimization for the RSM model observed an optimal response at 67.53% engine load, 99.998 ppm NDR, 12.084% BBR and 0.694 kg/h BFR, while an optimal response for the ANN model was observed at 79.11% engine load, 61.06 ppm NDR, 11.17% BBR and 0.776 kg/h BFR. The optimization study findings concluded that an optimal combination of nanoparticles, biodiesel, and biogas could significantly improve CI engine performance and emission responses.

Study of the Prevention Method of ±800 kV Transmission Tower Foundation Deviation

The stability of transmission tower bases is key to ensuring the safe operation of power lines. This paper proposes a joint displacement-control technique for foundation-inclined piles and prestressed foundation tie beams to address the problem of tower base displacement and durability degradation caused by environmental factors. A finite element model of an exposed-pile transmission tower conforming to the structural characteristics of the actual line tower was established based on the current situation of Tower 292 of the ±800 kV Tianzhong line in Xinjiang, China. Three different displacement-control schemes were analyzed under the combined effects of tower line load, ice-cover load, and wind load, including changing exposed pile height, changing inclined pile tilt angle, and increasing the prestressed foundation tie beam. The analysis shows that the combined displacement-control technology of foundation-inclined piles and prestressed foundation tie beams can reduce the horizontal displacement of EHV tower foundations by more than 50%, which greatly reduces safety problems caused by tower displacement and effectively improves tower durability.

Combined effects of heavy ion exposure and simulated Lunar gravity on skeletal muscle

BackgroundThe limitations to prolonged spaceflight include unloading-induced atrophy of the musculoskeletal system which may be enhanced by exposure to the space radiation environment. Previous results have concluded that partial gravity, comparable to the Lunar surface, may have detrimental effects on skeletal muscle. However, little is known if these outcomes are exacerbated by exposure to low-dose rate, high-energy radiation common to the space environment. Therefore, the present study sought to determine the impact of highly charge, high-energy (HZE) radiation on skeletal muscle when combined with partial weightbearing to simulate Lunar gravity. We hypothesized that partial unloading would compromise skeletal muscle and these effects would be exacerbated by radiation exposure. MethodsFor month old female BALB/cByJ mice were -assigned to one of 2 groups; either full weight bearing (Cage Controls, CC) or partial weight bearing equal to 1/6th bodyweight (G/6). Both groups were then divided to receive either a single whole body absorbed dose of 0.5 Gy of 300 MeV 28Si ions (RAD) or a sham treatment (SHAM). Radiation exposure experiments were performed at the NASA Space Radiation Laboratory (NSRL) located at Brookhaven National Laboratory on Day 0, followed by 21 d of CC or G/6 loading. Muscles of the hind limb were used to measure protein synthesis and other histological measures. ResultsTwenty-one days of Lunar gravity (G/6) resulted in lower soleus, plantaris, and gastrocnemius muscle mass. Radiation exposure did not further impact muscle mass. 28Si exposure in normal ambulatory animals (RAD+CC) did not impact gastrocnemius muscle mass when compared to SHAM+CC (p>0.05), but did affect the soleus, where mass was higher following radiation compared to SHAM (p<0.05). Mixed gastrocnemius muscle protein synthesis was lower in both unloading groups. Fiber type composition transitioned towards a faster isoform with partial unloading and was not further impacted by radiation. The combined effects of partial loading and radiation partially mitigated fiber cross-sectional area when compared to partial loading alone. Radiation and G/6 reduced the total number of myonuclei per fiber while leading to elevated BrdU content of skeletal muscle. Similarly, unloading and radiation resulted in higher collagen content of muscle when compared to controls, but the effects of combined exposure were not additive. ConclusionsThe results of this study confirm that partial weightbearing causes muscle atrophy, in part due to reductions of muscle protein synthesis in the soleus and gastrocnemius as well as reduced peripheral nuclei per fiber. Additionally, we present novel data illustrating 28Si exposure reduced nuclei in muscle fibers despite higher satellite cell fusion, but did not exacerbate muscle atrophy, CSA changes, or collagen content. In conclusion, both partial loading and HZE radiation can negatively impact muscle morphology.

Influence of bubble surface loading on particle-laden bubble rising dynamics in a fluid flow system

Prediction of the rising behaviour of particle-laden bubbles in turbulent flow systems is fundamental to the design and operation of industrial separation processes. However, due to the complexities of such systems, the effect of fluid flow on the rising behaviour of particle-laden bubbles is often ignored. This study examines the combined effect of bubble surface loading (BSL) (particle diameter: 115 μm and 316 μm) and fluid flow on the rising behaviour of a particle-laden bubble (bubble diameter: 2.10 ± 0.08 mm) in a flow system with a pair of counter-rotating vortices, at Reynolds numbers (Re) ranging from 188 to 769. Specifically. the rising trajectory, rise velocity, and aspect ratio of the particle-laden bubbles were determined using the shadowgraphy imaging technique. The results showed that the rise velocity reduces as the BSL increases, reaching a plateau at BSL values > 50%. Over the range of tested conditions, the critical BSL value was appeared to be insensitive to particle size but increased as Re increased. The diminishing bubble surface mobility is believed to be responsible for the observed trend. Further, a drag modification factor as a function of BSL and Reynolds number has been developed. Noticeably, the drag coefficient curves peaked at the corresponding critical BSL values. The drag modification factor may prove to be useful in modelling of the particle separation processes.

Thermomechanical fatigue of additively manufactured 316L stainless steel

An important issue in energy conversion is the performance of materials under complex cyclic loading in a variable temperature field. The present study addresses a new field of research – thermomechanical fatigue of additively manufactured metallic materials, which is crucial for understanding the behaviour of this promising material class under real operating conditions. The material of interest – 316L austenitic stainless steel, commonly used for heat exchangers – was manufactured to bars using laser powder bed fusion. Cylindrical specimens with characteristic hierarchical, non-equilibrium cellular microstructure were machined out of the bars. Two orientations corresponding to the inclination of the building direction to the specimen axis were considered: 0° and 90°. The specimens were subjected to thermomechanical fatigue loading under in-phase (maximum tension coincides with maximum temperature) and out-of-phase (maximum compression coincides with maximum temperature) conditions. The cellular dislocation microstructure showed good stability despite gradual coarsening under the combined effect of thermal loading up to 750 °C and severe plastic deformation. Systematic electron microscopy observations further revealed that basic damage mechanisms – either creep or stress-assisted oxide cracking, the prevalence of which depends on thermomechanical loading conditions – correspond to the behaviour of conventional metallic materials. Under in-phase loading, intergranular creep damage is dominant, hence a key factor affecting the lifetime is the number of grain boundaries in the loading direction. Under out-of-phase loading, fatigue damage is dominant, and the lifetime is determined by transgranular propagation of a principal crack. Comparing the two orientations, the inherent microstructural texture was found to be a crucial factor, also determining the number of grain boundaries and cell walls in the loading direction. Hence, tailoring the microstructure for the service relevant loading conditions via additive manufacturing techniques enables to enhance the component performance in the important field of energy conversion.

Experimental approach of contact mechanics for polyethylene materials with human skin under wet condition

As a lifestyle habit, shoppers like to lick their fingers before opening the polyethylene (PE) shopping bag. In fact, this implies a scientific problem, that is, moisture has an impact on the friction behavior between the plastic bag and the surface of the finger skin. In this study, an experimental method was employed to measure skin friction at three different hydration levels. The high-density polyethylene (HDPE) and low-density polyethylene (LDPE) materials were performed, and photographs of fingertips touching PE films were recorded by a camera. The experimental results showed that the applied normal load is positively correlated with the friction force and negatively correlated with the friction coefficient. And moisture content will increase friction. Specifically, when the fingertip slides on the HDPE film, the friction coefficient of the water-soaked skin is 5.9 times that of the dry skin. It can be inferred that the decrease in modulus of elasticity, as well as volume expansion, leads to an increase in contact area when the skin is wetted with water. This is the main reason for the increase in finger friction. In addition, a negative power function model was established to describe the relationship between the coefficient and the friction conditions by considering the combined effects of hydration level, normal load and material. Abbreviations: CCD: Charge-coupled Device; COF: Coefficient of friction; HbA1C: Hemoglobin A1C; HDPE: High-density polyethylene; LDPE: Low-density polyethylene; PE: Polyethylene; SC: Stratum corneum;

The Influence of Adiabatic Heat and Combined Blast Load and Fire Loading on the Response of Mild Steel Plates

This paper study the influence of adiabatic heat and fire loading on the behaviour of unstiffened mild steel plates subjected to close-in blast loads using finite element (FE) analysis. A quarter-symmetry 3D FE model consists of the steel plate, clamps and bolts was developed using Abaqus/CAE. Classical plasticity model was used as the material model in the steel plate and bolts. The clamps were assumed as an elastic material. Temperature-material properties relationship according to Eurocode 3 and Masui model was assigned to the steel plate. Conwep function was used to simulate the blast loads. The influence of strain rates was considered in the steel plate using the Cowper-Symonds equation. The FE model of the unstiffened plates was verified and validated against experimental data from literature, where a good agreement was achieved. The results suggest the adiabatic heat in the steel plates does not significantly influence the behaviour of the steel plates in both temperature-material properties models. The study then investigated the effect of combined blast loads and fire loading on the response of steel plates. The fire loading was applied by increasing the temperature in the steel from 200 °C to 1000 °C. Excessive deformation and thinning of the plate at the central area of the plate was observed. The thinning at the central area is pronounce than the thinning of the plate at the boundary between the clamp and the steel plate. Hence, the FE analysis suggests that the failure might occur at the central area of the plate, which could suggest a tearing type of failure. This type of failure is common in plates subjected to close-in blast loads. Therefore, this study has shown that the effect of adiabatic heat is insignificant, and the combined blast-fire loading might cause a similar type of failure as in plates subjected to blast loads only.

Structural performance evaluation of airport asphalt pavement based on field data measurement and finite element simulation

Airport asphalt pavement failure is caused by the combined effects of temperature and aircraft loading. Sensors have been effectively used to monitor the structural health of airport asphalt pavements. However, deploying sensors in multiple locations results in limited and discontinuous information. In this sense, finite element (FE) models are established to analyze the pavement service conditions at arbitrary locations in the airport pavement. First, sensors are used to measure pavement response and temperature data to verify the feasibility of the finite element method (FEM). Secondly, temperature index and performance-based zones of pavement structural layers are proposed based on the FEM. The proposed FE models demonstrate the feasibility of obtaining structural response and temperature distribution for performance zoning of different structural layers. This method improves the accuracy of performance evaluation through field data measurements, and provides guidance for the optimal design of airport pavement structure.

Structural performance of reinforced concrete beams subjected to combined effects of corrosion and cyclic loading

Structural performance of reinforced concrete beams subjected to combined effects of corrosion and cyclic loading