Value Of Tensile Stress Research Articles

A Modified B-Differentiable Equation Method for the Seismic Analysis of Arch Dams Considering the Initial Strength of Contraction Joints

For arch dams, the joint surface has a certain bond strength after grouting the contraction joints, which can withstand the arch-wise tensile stress to a certain extent and influence the stress distribution of the dam blocks on both sides. The seismic response analysis of arch dams needs to consider the influence of the initial tensile and shear strengths generated by the contraction joint grouting. Thus, a modified B-differentiable equation method is proposed by introducing the initial tensile strength and the initial shear strength of contraction joints the into traditional B-differentiable equation method. In the proposed method, the shear strength varies with the contraction joint opening. The modified B-differentiable equation method can still be solved by the B-differentiable damped Newton method with theoretical guarantee of convergence. Then, a seismic calculation model for the dam–reservoir–foundation system is developed based on the modified B-differentiable equation method, the Westergaard additional mass method, and multiple transmission boundary conditions. The influence of the initial tensile and shear strength of the contraction joints on the arch dam seismic response is discussed. The results show that the initial tensile and shear strength of the contraction joints have an influence on the opening and distribution range of the contraction joints and the maximum values of the principal tensile and compressive stress in the dam body. The initial tensile and compressive strength of the contraction joints should be considered when carrying out seismic response analysis of arch dams.

Visualization of time-varying effects of strain stress field under eccentric charge structure based on digital image correlation technique

This study determines the influence law of the maximum eccentric uncoupling coefficient on the pressure field distribution at the hole wall through theoretical analysis to investigate the time-varying effect of the maximum eccentric uncoupling coefficient on the stress field of an eccentric charge structure. The findings from the theoretical analysis indicate that when the maximum eccentric uncoupling coefficient (K) is 1, the pressure at the ring hole wall exhibits a circular distribution. As K increases, the pressure distribution at the ring hole wall becomes elliptical, with the elliptical eccentricity increasing progressively. This research employs an ultra-high-speed digital imaging system to assess the impact of the maximum eccentric uncoupling coefficient on the attenuation pattern of the stress field within the elastic vibration region. The results demonstrate that the eccentric charge structure’s effect on the strain field is predominantly observed in its time and strength effects. This is evident in the strain field’s time delay on the non-eccentric side and the fact that the strain field’s strength on this side is weaker than on the eccentric side. In the elastic vibration region, the primary type of radial stress is compressive, whereas the circumferential stress is chiefly tensile. As the measurement point’s distance increases, the peak values of both radial compressive and circumferential tensile stresses diminish exponentially. Interestingly, the attenuation index of the radial stress is notably lower than that of the circumferential stress. The change in the K value has a minimal impact on the attenuation indices of both radial and circumferential stresses. At equal distances from the eccentric side, the peak values of both radial and circumferential stresses display a consistent pattern with K and a linear pattern at distances from the eccentric side and in symmetry. The stress field’s intensity and attenuation pattern on the eccentric side remain largely unaffected by variations in K. Conversely, the stress field attenuation on the non-eccentric side is significantly influenced by K value changes, as is the symmetric side.

Experimental Study on Mechanical Performance of Single-Side Bonded Carbon Fibre-Reinforced Plywood for Wood-Based Structures.

In addition to the traditional uses of plywood, such as furniture and construction, it is also widely used in areas that benefit from its special combination of strength and lightness, particularly as a construction material for the production of finishing elements of campervans and yachts. In light of the current need to reduce emissions of climate-damaging gases such as CO2, the use of lightweight construction materials is very important. In recent years, hybrid structures made of carbon fibre-reinforced plastics (CFRPs) and metals have attracted much attention in many industries. In contrast to hybrid metal/carbon fibre composites, research relating to laminates consisting of CFRPs and wood-based materials shows less interest. This article analyses the hybrid laminate resulting from bonding a CFRP panel to plywood in terms of strength and performance using a three-point bending test, a static tensile test and a dynamic analysis. Knowledge of the dynamic characteristics of carbon fibre-reinforced plywood allows for the adoption of such cutting parameters that will help prevent the occurrence of self-excited vibrations in the cutting process. Therefore, in this work, it was decided to determine the effect of using CFRP laminate on both the static and dynamic stiffness of the structure. Most studies in this field concern improving the strength of the structure without analysing the dynamic properties. This article proposes a simple and user-friendly methodology for determining the damping of a sandwich-type system. The results of strength tests were used to determine the modulus of elasticity, modulus of rupture, the position of the neutral axis and the frequency domain characteristics of the laminate obtained. The results show that the use of a CFRP-reinforced plywood panel not only improves the visual aspect but also improves the strength properties of such a hybrid material. In the case of a CFRP-reinforced plywood panel, the value of tensile stresses decreased by sixteen-fold (from 1.95 N/mm2 to 0.12 N/mm2), and the value of compressive stresses decreased by more than seven-fold (from 1.95 N/mm2 to 0.27 N/mm2) compared to unreinforced plywood. Based on the stress occurring at the tensile and compressive sides of the CFRP-reinforced plywood sample surface during a cantilever bending text, it was found that the value of modulus of rupture decreased by three-fold and the value of the modulus of elasticity decreased by more than five-fold compared to the unreinforced plywood sample. A dynamic analysis allowed us to determine that the frequency of natural vibrations of the CFRP-reinforced plywood panel increased by about 33% (from 30 Hz to 40 Hz) compared to the beam made only of plywood.

Previsão de manutenção de pavimentos rígidos usando simulações numéricas e redes neurais artificiais

Abstract This work is concerned with the simulation of pavement behavior using the Finite Element Method (FEM) with the goal of predicting the appearance of cracks during its useful life. The developed method can help maintenance planning towards providing users with safety and comfort. The effects of both traffic loads and temperature variations are considered. Artificial Intelligence (AI) tools are adopted to reduce the time necessary for the interpretation of simulation results for the development of an efficient pavement management system. The developed rigid pavement management system uses the Artificial Neural Networks (ANN) technique for the prediction of both pavement response to fatigue accumulation and the behavior of the modeled pavement with a high degree of precision. The networks showed 4.5% and 3.6% square errors for positive and negative temperature gradients and 95% and 97% data correlation, respectively. The SR stress ratio obtained by the developed ABAQUS model is 0.614 and the value provided by the pavement management system is 0.648. The developed methodology was applied to a section of highway BR-101/NE, between the states of Paraiba PR and Pernambuco PE, in Brazil. Comparing the results with the limits provided by National Cooperative Highway Research Program (NCHRP) for traffic in the study, this pavement would require maintenance every six months. The maximum values of tensile stress due to bending were obtained by combining the positive temperature gradient with the traffic axis load at the edge during the summer months (December to March) due to the higher thermal gradient values.

Critical response analysis of asphalt pavement on concrete curved ramp bridge deck considering tire-bridge interaction

ABSTRACT This study developed a full-scale concrete curved ramp bridge deck finite element (FE) model, which considered the effect of tire-bridge interaction. In this full-scale FE model, an inflated tire model was developed to simulate the rolling tire load. The tire-bridge interaction equations were established based on the different interaction modes of the driving and driven wheels with the deck pavement. The effects of travel speed, curvature radius and load position on the critical response of bridge deck pavement was analysed. The results indicated that the deck pavement above the mid-span and flange cantilever panel exhibited greater critical tensile stress and strain values; whereas the bearing end diaphragm and the flange longitudinal diaphragm contributed the maximum critical shear stress. In the vertical depth direction, the damage induced by the traffic load mainly initiated at the deck pavement surface, and shear damage was more prone to occur between the layers of different paving materials. The reduced curvature radius and increased travel speed both promoted the appearance of unbalanced damage in the inner and outer tire loading zones. Besides, the smaller curvature radii and higher travel speeds would result in more severe local damage of deck pavement.

Determination of influence factores and stress concentration factor for express strength calculations of single-cut bolted connections of layered composite plates. Message 1

When designing bolted joints (BJ), it is necessary, in particular, to carry out their verification calculations for strength. At the same time, it is desirable to use express analysis: calculations by simple formulas of sufficient accuracy. For BJ of plates made of layered polymer composite materials (PCM), the problem has not been solved yet. Objective. To revise, to rethink and structure the formulas for the express calculation of the maximum stress when the hole is in contact with a rigid cylinder (bolt). Carry out a review on contrasting examples of materials and schemes of PCM plate reinforcement, taking into account possible lateral bolt/hole clearances in a practically relevant range, based on previously obtained and new results. Numerical calculations were carried out using the finite element method (contact problem) for the BJ plate made of laminated PCM. 3D orthotropy of each monolayer was assumed. Several simple express analysis formulas were checked, and their structuring was carried out. The results are summarized in a table, illustrations are given. Five factores influencing the value of the maximum tensile stress near the hole in the laminated PCM plate are separated. Numerical estimates were obtained that characterize the degree of influence on the stress concentration on the surface of the hole: material characteristics, reinforcement scheme, and bolt/hole gap sizes in the laminated PCM plate, as well as the accuracy of the considered formulas. A change in the material and scheme of reinforcement of the layered PCM leads to a significant change in the values ​​of the maximum stresses and stress concentration factor (SCF) in the bolt-loaded hole in the cross-section of the plate weakened by the hole. The considered express analysis formulas have insufficient accuracy for contrasting cases of materials and plate reinforcement schemes. Additional research is needed, especially for the reinforcement scheme [φ/-φ]2s at 0<φ<90.

Residual dentin thickness and biomechanical performance of post-and-core-restored mandibular premolars: A finite element analysis study.

Endodontically treated teeth often require post-and-core restorations for structural support because of extensive hard tissue loss. Assessment of the effect of the residual dentin thickness on the biomechanical performance of these restorations is lacking. The purpose of this study was to evaluate the residual dentin thickness in mandibular premolars after post-and-core restorations using cone beam computed tomography (CBCT) and to analyze the stress distribution with finite element analysis (FEA). The CBCT data from 236 mandibular premolars having undergone post-and-core restorations were examined. An imaging software program (NNT; NewTom) was used to measure the buccolingual and mesiodistal root diameters in cross-sections 5 to 11mm from the radiologic apex. The CBCT derived measurements were subsequently integrated into an FEA model. A 3-dimensional (3D) mandibular premolar model reflecting the residual dentin thickness was created with a computer-aided design software program (Hypermesh 9.0; Altair Engineering). A static force of 100N was applied directly to the buccal cusp tip at 45, 60, 75, and 90 degrees to the long axis of the tooth, and the stress distribution of dentin was analyzed by using an FEA software program (ANSYS APDL 18.0; Ansys Inc). CBCT analysis showed that the buccolingual root diameter was wider than the mesiodistal diameter and that the residual dentin thickness of the buccal aspect was approximately 0.3mm thinner compared with the lingual aspect along the root. The proportions of residual dentin thickness values in the buccolingual direction of the mandibular premolar teeth no less than 1mm exceeded 96.2% at 5 to 11mm from the apex. The proportions of residual dentin thickness values in the mesiodistal direction of the mandibular premolar teeth >1mm were 92.1% and 88.2% at 11mm from the apex after post space preparation and decreased further to 70.8% and 58.9% at 5mm from the apex. The von Mises stresses of the mandibular premolar model with residual dentin thickness were mainly localized to the cervical area (region C, cervix) and the post apex (region A, apex) in the buccolingual direction. Tensile and compressive stress were concentrated on regions C and A on the buccal and lingual sides, respectively. The actual residual dentin thickness model demonstrated higher maximum tensile stress compared with the 1-mm residual dentin thickness model under various loading conditions. During the process of post space preparation in mandibular premolars, sufficient dentin thickness should be retained in the apical region. The tensile stresses of mandibular premolars after clinical post-and-core restoration were mainly concentrated in the cervical area and the post apex, and the maximum tensile stress value was higher than the ideal 1-mm residual dentin thickness model.

COMPARATIVE REVIEW OF PROPERTIES OF STEELS USED IN NIGERIA TO FORESTALL BUILDING COLLAPSES

This research analyzed the mechanical properties of reinforcing steel bars used in Nigeria and compared them to four different standards (AISI 1018, ASTM A706, BS4449, and NST-65-Mn). This was done as a result of frequent building collapses in Nigeria, which has revealed the knowledge gap between what the designers expect and the true mechanical properties of the products they typically receive from manufacturers. Related literature from published articles was collected and analyzed based on the mechanical properties of locally produced and imported steels. Results showed that the tensile strength, yield strength, hardness, percentage elongation, and percentage carbon composition of most products met and exceeded the requirements of AISI 1018, ASTM A706, BS4449, and Nst-65-Mn when compared, while some fell below what these standards required. Federated Steel Mills Limited, Ogun State, has the highest tensile stress value at 799.49 MPa, followed by Real Steel Reinforcing Pty Limited, Auckland, New Zealand, at 726.34 MPa, and Landcraft Industries Limited, Ikorudu, Lagos, at 708.3 MPa, according to a yield and tensile strengths analysis of 16 mm steel bars produced locally and imported. The lowest tensile strengths ever reported are 410 MPa for African Steel Nig. Limited, Ikorodu, Lagos, and 538.51 MPa for steel imported from Brazil. It is hoped that the data from this study will bridge the knowledge gap between the team players in this field, thus preventing catastrophe.

Sustainable polyurethane biocomposite foams by improved microstructure, acoustic characteristics, thermoregulation performance and reduced CO2 emission through phase change material integration

In this research, phase change material (PCM) comprised of energy storage biocomposite materials were improved with raw materials obtained from renewable resources. Modified raw material was synthesized by epoxy castor oil (ECO). After mixing the obtained modified castor oil (MCO) and polyether polyol, PCM of capric acid (CA) was supplemented. To initiate the chemical reaction, a certain amount of methylene diphenyl diisocyanate (MDI) was added to the mixture to provide cross-linking. The physical and chemical properties of the resulting biocomposite foams (BCF) were characterized. According to the results obtained, mixing MCO into polyether raw material increased the number of closed pores in BCF resulting in more CA stored in BCF cells produced. The use of MCO in BCF materials increased the CA integration ratio to 68 wt%. The melting enthalpy value of the novel BCF-PCM composites has been determined as 121.43 J/g. In a warm environment, the PCM additive creates a temperature difference exceeding 6 °C, while in a cold environment, it provides a cooling effect close to 6 °C. A more than 50 % improvement in thermal conductivity was achieved with 68 wt% PCM addition compared to pure BCF. The addition of PCM caused a reduction in tensile stress and strain values to an acceptable level. BCFs with PCM additives exhibit a sound absorption coefficient of 0.9 in narrow frequency ranges, whereas, in broad frequency ranges, this value was more than 0.7. In cold weather conditions, employing BCF-PCM material instead of traditional EPS material with a thickness of 0.1 m has led to at least a 30 % drop in CO2 emissions, no matter the type of fuel used for heating. When opting for BCF-PCM materials, the necessary heat demand was approximately 33 % less compared to using the same thickness of EPS in cold climates.

Preparation and characterization of modified CNC/waterborne polyurethane composite film

To improve the water resistance and mechanical performance of waterborne polyurethane, modified cellulose nanocrystal (CNC) as a kind of environmentally friendly material was added into the solution of waterborne polyurethane by the in-situ polymerization and mechanical blending way, and two different modified CNC/waterborne polyurethane composite films were prepared. The results show that due to the addition of modified CNC, the composite film prepared by in-situ polymerization way showed much better behavior in both water resistance and mechanical properties than that made by the mechanical blending method. When the content of modified CNC was 5% in the composite, the water resistance of the composite film increased by 34.6%. At the same time, the tensile property of the composite film was improved when using in-situ polymerization to fabricate the film, and the value of maximum tensile stress rose by 143.9%.

Pengaruh Penambahan Serat Pohon Bambu Ampel (Bambusa Vulgaris) pada Komposit Hybrid untuk Material Bumper Kendaraan Bermotor

Technological developments continue to increase in line with the times, producing various innovations that provide benefits to society, especially in the material sector. The use of a mixture of natural and synthetic fibers in composites (hybrid) has produced a stronger material, which can function as an alternative material for car bumpers. This research was carried out with the aim of determining the values ​​of impact toughness, tensile strength, and failure patterns that occur in the fracture cross section of the specimen through macro photographs. In this research, a hybrid composite was formed by combining ampelous bamboo fiber, fiberglass, and polyester resin. Variations in volume fraction applied include: 5%:25%:70%, 10%:25%:65%, and 15%:25%:60%. The specimens were formed according to ASTM E23 standards for impact tests and ASTM D638 for tensile tests. The results of the impact and tensile tests showed that the lowest value of impact toughness was 0.0744 J/mm² and tensile stress was 120.29 MPa. Meanwhile, the highest value for impact toughness was 0.0986 J/mm² and the tensile stress value was 147.65 MPa. Macro photo analysis of the fracture cross section is categorized as splitting in multiple areas and the fracture cross section also shows debonding and fiber pull out after the fracture occurred.

The impact of bedding planes on microwave-induced damage in rock at the field scale: a numerical model

The feasibility of microwave heating-assisted rock breakage technology in geotechnical engineering has been widely explored. However, the limited knowledge of the impact of the contrast properties between different bedding planes and outer formation stresses limits its application at the field scale. In this work, the mechanics of mineral processing, rock breakage, and unconventional gas and oil exploitation were first characterized. A coupled model is subsequently proposed to govern the coupling process of microwave heating and induce inhomogeneous deformation and stress in various bedding planes. Three stress forms are considered in this approach: horizontal stress, normal stress, and shear stress. With the assistance of the finite element method, the stress conditions of bedding planes composed of rock under free swelling, constant stress, and constant volume were addressed. A bedding plane characterized by high microwave adsorption ability is usually compressed by a bedding plane characterized by low microwave adsorption ability. The bedding ore is under the condition of free swelling during mineral processing, whereas in the remaining two scenarios, the bedding rock is stress controlled. The tensile and compressive stresses can reach their maximum values under the condition of free swelling. The outer formation stress reduces the values of tensile and compressive stresses but has little impact on the shearing stresses. Additionally, this work provides criteria for defining an a priori evaluation of the effectiveness of microwave treatment of bedded ore and rock for different geotechnical engineering applications.

Combined effects of carbon content and heat treatment on the high-temperature tensile performance of modified IN738 alloy processed by laser powder bed fusion

Laser powder bed fusion (LPBF) is an advanced manufacturing technology used in processing nickel-based superalloys, notably for aero-engine components. One such material, the LPBF-fabricated IN738 superalloy, is prone to significant cracking issues. This study found that a change in carbon content (the optimal content of which was also determined) effectively mitigated the cracking. This study has systematically investigated the impact of different heat treatments on microstructural alterations and high-temperature tensile properties. The addition of 0.55 wt% of graphite proved effective in entirely inhibiting cracking in LPBF-fabricated IN738 specimens. Pre-alloyed IN738-M powder with the optimal carbon content was then produced and processed via LPBF to assess its formability. The as-built specimen revealed the presence of continuous carbides along the subgrain boundaries. Heat treatment promoted the transformation of substructured grains into recrystallised grains, accompanied by the precipitations of carbides and the γ′ phase; their morphologies were strongly determined by the solution treatment temperature. Differential scanning calorimetry measurements were employed to elucidate the differing microstructural states following distinct heat-treatment regimens. Under a 900 °C testing condition, stress-relieved (SR) specimens were found to exhibit superior performance, demonstrating an ultimate tensile stress (UTS) value of 843.6 MPa, a yield strength (YS) of 807.3 MPa and an elongation of 8.54 %. Notably, SR specimens also exhibited the highest UTS and YS values at 1000 °C, measuring 380.0 MPa and 346.5 MPa, respectively. This study's findings will furnish valuable insights for researchers who aim to enhance the high-temperature tensile performance of LPBF-fabricated nickel-based superalloys.

Stress–Strain Response of AISI H13 Steel Subjected to Cyclic Thermomechanical Loading

ABSTRACTThis study investigates the stress–strain behavior of AISI H13 hot work die steel under thermomechanical fatigue (TMF) conditions. An electromagnetic‐thermal‐mechanical coupled finite element model was established to analyze the temperature and stress evolution during TMF cycles. Experimental results reveal that as TMF cycles increase, the hysteresis loop areas expand, and maximum tensile and compressive stress values decrease, indicating cyclic softening of AISI H13 steel. After undergoing TMF, observations show martensitic lath recovery and carbide coarsening along boundaries. Numerical results indicate thermal cycles cause temperature field inhomogeneity along the axial direction, which leads to a non‐uniform distribution of internal stresses along the longitudinal axis. Besides, the TMF lifetime under numerical simulation is comparable to that obtained through experiments. Based on experimental and simulation data, four life prediction models are employed, with the Ostergren model showing the highest consistency with a reliability factor of 1.2.

Mechanical Properties of Novel Hybrid Bamboo Fibre/Aluminium Mesh Reinforced Polymer Composite

Bamboo fibres are one of the sustainable lignocellulosic resources explored for polymer composites in recent years. Research has shown that bamboo fibres have the potential to be used in a variety of critical applications. Nevertheless, bamboo fibres are susceptible to thermal and hygroscopic loads, and their mechanical properties are limited by the unequal interfacial strength and varying fibre dimensions. Implementing hybrid procedures or incorporating alternative materials, such as aluminium metal, is strongly advised to address this issue. Thus, this study investigates the tensile and flexural performances of the hybrid bamboo fibre/aluminium expanded mesh-reinforced polymer composites. The composites were fabricated using epoxy resin reinforced with bamboo fibre, and an aluminium expanded mesh sheet was constructed using a vacuum infusion process utilising various stacking sequences and mesh sizes. The test findings indicated that the composite material exhibited tensile stress values ranging from 27 to 34 MPa and a corresponding tensile strain value between 1.1% and 1.6%. The flexural strength and strain values were measured within the range of 44 Mpa to 59 Mpa and 2.2% to 3.2%, respectively. ANOVA analysis showed that both stacking sequences and mesh size significantly affected the tensile performances of the composites, while only stacking sequences affected the flexural performance significantly. Overall, a hybrid composite of bamboo fibre and aluminium mesh is well-suited as a substitute material in industries requiring exceptional mechanical properties.

A refined method for designing the strength of normal cross-sections of eccentrically compressed concrete elements with composite polymer reinforcement

Introduction. The operating standards for the design of concrete structures with composite reinforcement SP 295.1325800.2017 do not consider the work of compressed reinforcement when calculating eccentrically compressed elements. The previous studies proposed a method for calculating the strength of normal cross-sections of eccentrically compressed elements. Though this method has shown a reasonably high agreement with the experimental data, it has also indicated some underestimation of the load-bearing capacity of such elements. In this paper, a further analysis of the developed method is performed and suggestions for its refinement are formulated in order to identify additional reserves of strength of concrete elements reinforced with composite reinforcement.Aim. To refine the method for designing the strength of normal cross-sections of eccentrically compressed concrete elements with composite reinforcement, to compare the refined method with experimental and theoretical data, as well as to assess its reliability.Materials and methods. Theoretical studies are based on the results of the tests that included the experimental examination of concrete samples reinforced with composite reinforcement under the action of eccentrically applied static compressive load consisting of four series of specimens with a total of 12 specimens.Results. The suggestions were formulated for specifying the value of the height of the compressed zone, as well as the value of tensile stresses in composite reinforcement for designing the strength of normal cross-sections of eccentrically compressed concrete elements with composite reinforcement.Conclusions. Based on the analysis of experimental data, a refined methodology for designing the strength of normal cross-sections of eccentrically compressed concrete elements reinforced with composite reinforcement is proposed. In addition, the assessment of the proposed refined method is carried out, which proved to have the required level of reliability, while providing the best convergence with the experimental data.

ANALISA KEKUATAN TARIK DAN LENTUR KOMPOSIT BERPENGUAT SERAT DAUN NANAS (ANANAS COMOSUS) DENGAN KONFIGURASI CROSS-PLY LAMINATE

Composite is a new type of material which is the result of engineering, consisting of two or more materials, with the properties of each material being different from each other both in terms of chemical and physical properties. The aim of this research is to determine the tensile and flexural strength values of pineapple leaf fiber composites with a cross-ply laminate configuration with fiber arrangement angles [0, 90°, 0°], [45˚, -45˚, 45˚] and [ 30°, -30°, 30°]. This research uses fiber arrangement directions [0, 90°, 0°], [45˚, -45˚, 45˚] and [30˚, -30 ˚, 30 ˚] with a cross-ply laminate configuration and uses. The composite was made in a composite mold measuring P = 190 mm, L = 90 mm and t = 5 mm. The results of this research show that the influence of the pineapple leaf fiber orientation angle on the average tensile stress value of composites with pineapple leaf fiber cross-ply laminate configuration with the highest tensile stress value is shown by the fiber direction at an angle of [30°, -30°, 30°] amounted to 27,611 MPa, while the lowest composite value with the angle [45˚, -45˚, 45˚] was 19,407 MPa. The highest bending stress value is found in the composite with an orientation angle of [0, 90°, 0°] with an average value of 59.002 MPa, while the composite with a fiber orientation angle of [45˚, -45˚, 45˚] has a higher bending stress value. low at 32.974 MPa.

A case study comparing seismic retrofitting techniques for a historically significant masonry building’s minaret

Historical masonry structures are extremely susceptible to earthquakes due to their characteristic features. Seismic performance and corresponding damage patterns vary between these buildings. Even though the main structure was undamaged, many minarets suffered damage or collapsed due to the transmission of large forces from the main mass to the minaret and the abrupt changes in cross-section due to the geometry of the minaret. This study uses an ancient masonry mosque as a case study, whose minaret and main building are constructed as a single structure. The mosque’s minaret under seismic excitation is the focus of this study. The adopted model is called Alaeddin Bey Mosque in Muş, Türkiye. The seismic performance assessment of the minaret, considering various retrofitting options, is mainly based on four critical parameters: base shear, acceleration, displacement, and maximum tensile forces in all three dimensions. The analyzed retrofitting methods include base isolation located in the basement of the mosque, viscous dampers placed only in the upper part of the minaret, Carbon Fiber-Reinforced Polymer fabric fitted to only the minaret, and steel plates applied to only the minaret. Representative structural models of the mosque have been modelled with SAP2000 software. The main novelty of this study is the use of viscous dampers in the minaret. It is the first time a design methodology has been introduced for viscous damper applications in minarets. This methodology aims to prevent local damage to the minaret due to the forces generated by the dampers, while also considering the constraints of limited internal space within the minaret. The finding of this study shows that viscous damper application yields significantly better results compared to the application of Carbon Fiber-Reinforced Polymer fabric and steel plates. However, although base isolation reduces the tensile stress values throughout the entire mosque to levels well below the material’s strength, viscous damper application in the minaret significantly reduces tensile stresses only in the minaret. As a result, viscous dampers are recommended for damage reduction in the minaret only. Otherwise, base isolation should be considered for reducing stress values throughout the entire mosque including the minaret. This study contributes towards the development of new seismic retrofitting methods for historic masonry buildings ‘minaret.

Study of bond strength and electronic properties at the 6H-SiC/Al interface: Based on first-principles calculations

As the medium between the reinforcement and the matrix, the interface plays a critical role in the mechanical properties of silicon carbide particle reinforced aluminum matrix composites. This study used first-principles calculation methods to systematically analyze 14 different 6H-SiC/Al low-index interfaces, including atomic configuration, interface bonding strength, and electronic structure and bonding principles between interfaces. The adhesion work calculations reveal that the C-top-SiC(0001)/Al (111) and SiC(0001)/Al (100) interfaces have larger adhesion work values, specifically 5.09 J/m2 and 5.021 J/m2, respectively. Additionally, the rigid tensile testing confirms that the tensile stress values at the interfaces of C-top-SiC(0001)/Al (111) and SiC(0001)/Al (100) are higher, measuring 36.4 GPa and 32.5 GPa, respectively. The above results show that the interface bonding strength of these two configurations is the highest, the most stable, and most likely to appear in the 6H-SiC/Al interface configuration. The results of the analysis on charge density difference and partial density of states indicate that the interfaces of C-top-SiC (0001)/Al (111) and SiC (0001)/Al (100) are primarily composed of strong ionic and covalent bonds.

Stress-Strain Analysis of the Fretting and Non-Fretting Steel Wire: An Experimental and Simulation Study

Fretting wear is one of the main degradation mechanisms produced in steel wire and it is widely used for the lifting and handling of equipments. The main objective of the present work is to analyse the mechanical properties of the fretting and non-fretting wire. Statics tensile tests were performed on non-fretting wire and pre-damaged artificially fretting wire subsequently, after that tensile stress (σT), tensile strain (εT), and breaking load (BL) were measured for both wires and their basic mechanical properties were compared. For the analysis wire diameter values varies from 7 mm to 9 mm and artificially pre-damaged wire having reduced diameters varies from 5.8 mm to 8.1 mm were used. From these tests the basic mechanical properties values of maximum tensile stress, tensile strain, modulus of elasticity (E), breaking load (BL) 1610 N/mm2, 12.08%, 78854.3 Mpa and 56.73 KN respectively were obtained, for pre-damaged artificially fretting wire. On the other hand, for the non-fretting wire, the values of maximum tensile stress, tensile strain, modulus of elasticity, and breaking load have been obtained as 1171.5 MPa,16.40 %,63289.4 MPa and 58.7 KN respectively.