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This paper investigates the effect of fiber on the behavior of punching shear slabs; a finite element modeling approach is used to simulate the case study. The proportion mix of hybrid fiber-reinforced concrete, which contains 0.2 percent macro synthetic fibers and 0.68, 0.8, and 0.96 percent steel fibers, compressive strengths of 50 MPa, different longitudinal reinforcement used, and slab thicknesses of 150, 200, and 250 mm are all joined and investigated in this study. The ATENA software is used to perform nonlinear finite element analysis. The slab results validation was done similarly to previous experimental work, and the acquired results indicated a significant agreement. Thirty-six two-way specimen slabs with dimensions of 1900 × 1900mm were modeled in this investigation. All four sides of the slabs are supported. The results showed that the slabs' ultimate shear capacity increases with increasing the hybrid steel fiber. Nevertheless, the ultimate capacity of the slabs has decreased due to an increase in the reinforcement ratio and slab thickness. [ABSTRACT FROM AUTHOR]

From past to present, building designs and materials used are developing. Especially against the destructive effects of ground movements and free vibrations on structures, many structural system designs and composite structure designs have been developed. The purpose of the composite structure design is to choose different types of materials according to the structural load-bearing system stress, in short, to choose the most advantageous material type according to the cross-sectional stresses or to eliminate the negative aspects of one material with the positive aspects of another material. It is a known fact that the dynamic performance of steel structure carrier systems is high under the influence of ground movements and free vibrations. However, in cases where the section geometry cannot be changed due to architectural concerns due to architectural design difficulties, there are cases where the rigidity of the structure is not sufficient. In such cases, profiles made of different materials other than steel can be used in order to increase the rigidity of the structure, especially in the columns, which are a very important component of the structural load-bearing elements. Therefore, in this study, the effect of using molybdenum profile instead of steel profile on modal parameters in model steel structure columns was investigated. In the light of the information obtained, a decrease of approximately 23.72 percent was observed in the period value in the 1st free vibration mode of the steel-molybdenum structure model. Thus, it is understood that the rigidity of the model steel structure system increases. In cases where it is not possible to change the architectural design in steel structures, it is recommended to use column profiles as molybdenum profiles instead of steel profiles in order to provide the necessary rigidity and increase rigidity. [ABSTRACT FROM AUTHOR]

The elevator car moves up and down by means of guide rails on a pedestal inside the hoistway. Guide rails can be damaged during movement due to the stresses caused by suddenly movement waves. The study was carried out to determine the stresses that occur in the guide rails during sudden movement fluctuations. In the study, the traffic calculation of a 10- person elevator with 2 apartments on each floor of 10 floors was taken into account. The stresses that will occur in the car guide rails depending on the car loadings were investigated in ANSYS21.R2 with ANSYS Workbench, where a maximum load of 6300 N acts on the car floor and with a finite element analysis with a safety factor of 1,5. Theoretical and analysis results were compared. Theoretical and analysis results were compared. Theoretical Normal stress is 3,407 MPa, Von-misses stress is 5,735 MPa, normal stress is 12,182 MPa and Von-misses stress 17,933 MPa in the analysis for the centrally guided suspended cabin safety condition. For decentralized cabinet safety situation, stresses were obtained 4,32 and 7,705 MPa Normal stress, Vonmisses stress in theory, 15,401 and 22,4 MPa Normal stress and Von-misses stresses in analysis, respectively. In the sideguided cabin safety gear, the theoretical Normal stress was 9,052 MPa, the Von-misses stress was 12,438 MPa, the normal stress was 31,139 MPa, and the Von-misses stress was 48,234 MPa in the analysis. As a result, it was seen that the normal and Von-misses stresses obtained in theory were lower than the normal and Von-misses stresses obtained in the numerical analysis. Accordingly, it has been determined that the most suitable cabin type is the centrally guided cabin type. [ABSTRACT FROM AUTHOR]

Brushless Direct Current (BLDC) motors are known as synchronous motors and used in industrial areas due to their advantageous features. NdFeB magnets used in BLDC motors and produced at different power levels of rare earth elements are preferred due to their excellent magnetic properties. Although physical factors and environmental conditions have an effect on permanent magnets, the performance values are determined by the maximum energy efficiency (BHmax), residual flux density (Br,) and intrinsic coercive force (Hei) parameters. In this study, Alnico, Ceramic, SmCo and NdFeB magnets used in BLDC motors with permanent magnet rotor structure and the effects of these magnets on motor performance parameters are analyzed. For motor performance, magnet types are compared by considering speed, efficiency and torque values. The magnetic properties of the NdFeB are determined by analysis comparisons. Therefore, the effects of the types of these magnets obtained at different power degrees (N28-N38-N42-N52) on the engine performance are included in the study by considering the operating conditions at different temperatures (20°C, 60°C, 80°C). In the study, the effects of NdFeB on motor heat transfer are determined by an inner mounted rotor IPMBLDC motor with 2.45 kW power, the analysis made with finite element method (FEM). [ABSTRACT FROM AUTHOR]

The most important dynamic parameter to be known in the design and optimization of soil tillage tools and machines is the draft force. Today, the draft force in soil cultivation tools and machines can be determined by different methods. These are experimental, analytical, and numerical methods. Among the numerical methods, especially the finite element method has been widely used in the design of soil tillage tools and machinery and in the estimation of the draft force. The use of the finite element method in the soil-machine relationship has provided great convenience and economy in the design, optimization, and evaluation of new equipment and machines. One of the important software used to define the soil-machine relationship is ANSYS. ANSYS has been used in this study because it is a powerful numerical software program that analyzes the soil-machine relationship using the finite element method and gives very close results by entering real soil parameters and boundary conditions into the simulation. In the study, shares with different mouth structures (flat, pointed and fork-shaped) that can be used for cultivators were used. The draft force values of shares at different operating speeds (1.5 m s-1, 2.5 m s-1, and 3.5 m s-1) were determined. There are buried soil models in ANSYS and the draft force values obtained with the cultivator shares were determined by using the Drucker and Prager model among these models. This model is stated as the best model representing the soil-machine relationship. It was determined that the draft force increased with the increase of the forward speed. However, it was determined that the fork share was less affected by the speed increase compared to the other shares. This situation has made this cultivator shares a more important position than the others. The highest draft force was found to be 1.64 kN with the flat share at a forward speed of 3.5 m s-1. The lowest draft force was found to be 0.39 kN with the fork share at a forward speed of 1.5 m s-1. [ABSTRACT FROM AUTHOR]

Dual-phase (DP) steels are becoming more and more popular for automotive applications. They offer a weight reduction with a combination of energy absorption for crash zones. Rails, reinforcements, back panels, cross members, and pillars can be given as application examples. DP steels microstructure consists of a soft ferrite with hard martensite. The martensite provides strength while the ferrite provides ductility. The strength level of DP steel is correlated with the martensite fraction in the microstructure, and the fraction of martensite can be controlled via intercritical annealing. In this work, thermodynamic analysis of St52 steel was carried out with Thermo-Calc software. A1 and A3 temperatures were determined by calculating the temperaturedependent phase fractions. Intercritical annealing temperatures were determined according to the calculated critical temperatures (A1 and A3). The intercritical annealing process was modelled by using Simheat NxT software. In this modelling and simulation study, the intercritical annealing temperature impact on the final microstructure and hardness of DP steel was investigated. [ABSTRACT FROM AUTHOR]

Every object in nature has an infinite number of vibrational frequencies and amplitudes called "Natural Vibration Frequency". Thanks to the developing computer technology, the calculation of the natural frequencies of complex structures are carried out quickly and accurately. In this study, the natural frequencies of the industrial sponge crushing machine were analyzed by finite element methods. The finite element method is one of the most common numerical methods used in solving many engineering problems from solid mechanics to acoustic problems. Vibration analysis of the solid model of the designed sponge crushing machine was carried out using the finite element method with the help of the widely used ANSYS Workbench 18.1 program. In the analysis, the components that make up the system were modeled separately and the system as a whole and the results were compared. The natural frequency values obtained in the finite element analysis were presented in tables and graphics. [ABSTRACT FROM AUTHOR]

In this study, the dynamic instability region of cracked composite plates subjected to periodic axial loading has been investigated numerically by using the finite element method. A composite plate based on classical lamination theory is modeled by using the finite element method. It is assumed that the boundary condition of the composite plate is fixed on one side and the other sides are free. The composite plate is divided into square plate elements, each having four nodes. Each node has one translational and two rotational degrees of freedom, therefore, the square plates have twelve degrees of freedom. Mathieu-Hill type motion equation, which is used to calculate the dynamic instability region of the plate is created by using energy expressions obtained from the Lagrange equation. The developed MATLAB finite element code is used to examine the effect of crack on dynamic instability region for composite plates. [ABSTRACT FROM AUTHOR]

Microwave cancer therapy is an effective method used to destroy cancer cells which eliminates the need for surgical intervention in diseases such as breast and liver cancer. The present study aims to present a methodology for the destruction of killing the malignant cells in a wider periphery by means of burning in a shorter time meanwhile causing minimal damage to the healthy tissues. The study is carried out for a frequency value of 2.45 GHz and for a power value of 10 W using finite element methods. A comparison between coaxial single-slot antenna and double-slot antenna is conducted for liver and breast tissues. Investigated parameters are the slot number, the type of the tissue and the duration of microwave cancer therapy. The specific absorption rate and temperature distribution are the examined parameters. The results of the study show that both peak specific absorption rate and peak temperature value are obtained for microwave coaxial single slot antenna within the liver tissue, and it is observed that the temperature distribution depends on time. Maximum temperature value is attained as 93.9oC and 82.8oC for single and double slot antennas for liver tissue whereas the so-called values are 93.0oC and 69.8oC for breast tissue. New correlations are given for the treatment of liver and breast tissues using coaxial single slot antenna. It is anticipated that the present study makes a contribution in the field of medicine. [ABSTRACT FROM AUTHOR]

This study presents the crashworthiness performance of Al6061 tubes with stiffened quatrefoil sections under axial and oblique impact conditions. Influences of different types of stiffeners through the depth of tubes in the design of a quatrefoil sectional crash absorber structure are investigated, numerically. Four types of stiffener patterns are considered under oblique impact angles of 0º, 10º, 20º, and 30º measured from the horizontal axis. Force-displacement characteristics, deformation patterns, and crashworthiness indexes of the tested tubes are given to decide optimal crash absorber configuration. The numerical tube models are placed between two rigid plates and an axial impact speed of 1m/s is considered in the numerical study. Al6061 series aluminum alloy is used as a tube material with a multi-linear material model assuming strainrate independent properties. It is found that the crashworthiness performance is very sensitive to impact angle and Q-S-4 type stiffeners can be proposed for a better tube design. [ABSTRACT FROM AUTHOR]

In this study, the fatigue analysis of the vehicle brake disc was simulated using the finite element program, and life calculations were made in accordance with the analysis. The main purpose is to simulate experimental tests, which take a long time to result, in the computer environment and to obtain results in a short time and at a very low cost. With the help of the ANSYS computer program, which operates with the finite element logic, the disk brake system was created in three dimensions, and the boundary conditions closest to reality were determined and analyzed using the finite element method. In the disc brake system selected, the data obtained by conducting stress, fatigue life, and safety coefficient analyses in line with the forces formed on the wheel and the vehicle during braking were examined. According to the analysis results, our brake disc is in different life ranges in accordance with the material used and the load applied, and when the force is increased, the life decreases and vice versa. [ABSTRACT FROM AUTHOR]

Historical buildings are an integral part of cultural heritage all over the world and are structures that carry the traces of the past to the present, together with the universal values they have. Although historical buildings, which generally have a masonry bearing system, have a better seismic performance compared to reinforced concrete structures, it is understood that some of these structures have suffered serious structural damage in some destructive earthquakes. Although many studies have been conducted to determine the seismic performance of historical buildings, there is no method that has been determined with strict lines to evaluate the performance of these structures. Within the scope of this study, a simplified method based on displacement was emphasized in order to determine the seismic performance of historical buildings and the seismic performance of historical Kaya Çelebi Mosque, which was damaged after the 2011 Van earthquake, was examined using this method. [ABSTRACT FROM AUTHOR]

Chromium Coated parts which are widely used inside and outside of a vehicle are exposed to different external conditions. Corrosive and thermal effects can be observed on the part due to rain, dust and sun. In this study, a finite element method is developed in order to anlyze the thermal deformations which may lead cracks on chromium coated parts, The layers of the coating are modelled seperately. The effects of the thickness of the layers and the geometric changes on the fracture were investigated. [ABSTRACT FROM AUTHOR]

Almost all vehicles that manufactured in present, snap-fit which are so flexible and can be locked after insertion are used for mounting sub-assemblies such as internal trim, external trim, closures etc. By using this type connection, plastic parts of sub-assemblies can be mounted or dismounted. At this point, calculation of loads while mounting-dismounting become the most important variables for design and verification after design in lifetime cycle. In this study, mounting - dismounting load calculated by using two dimensional (2D) finite elements methods for a snap - fit connection which used in a vehicle's covering plastic parts of internal trim. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of own weight on the dynamic analysis of a pre-stretched composite platestrip containing a circular hole subjected to bending load. The combined effect of body forces (weight) and surface forces (pre-stretching load) on the plate-strip with a hole is considered as the initial stresses determined within the linear theory of elasticity. The effects of these initial stresses on the natural and forced vibrations around the hole within a plate-strip under additional bending load are investigated in the framework of the Three-Dimensional Linearized Theory of Elasticity (TDLTE) under the plane strain state, and the solutions of the considered boundary value problems are solved numerically by using the finite elements method. This paper shows that the influence of the plate's own weight has an important role on the dynamic analysis around the circular hole within a plate-strip. [ABSTRACT FROM AUTHOR]

The aim of this research is to examine the mechanical buckling behavior of multi-layered functionally graded beams in the axial direction. Numerical buckling analyses were performed using finite element software called ANSYS. Each beam configuration is suggested to be three layers prepared using various percent volume fractions of Zirconia (ZrO2) and Aluminum (Al) materials. The levels of layers and layer positions of the beams were evaluated according to Taguchi's L9 (33) orthogonal array technique. Layers were determined as control factor and so nine numerical analyses were performed under clampedclamped boundary conditions. The first mode shapes of the axially layered functionally graded beams were demonstrated in order to detect the most affected layers as visually. Analysis of signal-to-noise ratio was applied to obtain the optimum levels of layers. Analysis of Variance (ANOVA) was employed to solve the layers with significant impacts and their percent contributions on numerical results. The maximum buckling load was determined using various positions of layers with the optimum levels obtained based on Taguchi methodology. [ABSTRACT FROM AUTHOR]

This article presents the mechanical design procedures that were devised for the development of series elastic actuators (SEA), a type of actuators that enable joint level torque control of robots. These procedures include the synergistic combination of studies that were conducted via simulation and CAD software whose outcomes were experimentally verified, with a special emphasis on the torsional spring, the most crucial element in the unit. Technical difficulties and shortcomings that were encountered in the first version of the actuator are disclosed with the help of experimental data. The article is concluded with the results from the ready-to-use 2nd version of our SEA. [ABSTRACT FROM AUTHOR]

This study investigates the flexure analysis of functionally graded (FG) plates using {2,2}-refined zigzag plate theory which considers transverse normal deformation along the thickness of plates. This element eliminates the use of the shear correction factors. The FG plate is composed of silicon carbide (SiC) and aluminum (Al) varying through the thickness of the plate. The volume fractions of the material constituents in the FG plate were functionally tailored based on a power-law. The effective material properties of the plate were evaluated by using the Mori-Tanaka homogenization method. The accuracy of the present approach was demonstrated by considering a simply supported FG plate under distributed sinusoidal load. The influence of the through-thickness material variation on the stress and displacement distributions was investigated. It was observed that the material variation through the thickness played a major role on the stress and displacement levels whilst the influence of the material variation was minor on the stress and displacement profiles. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of own weight on the dynamic analysis of a pre-stretched composite plate-strip containing a circular hole subjected to bending load. The combined effect of body forces (weight) and surface forces (pre-stretching load) on the plate-strip with a hole is considered as the initial stresses determined within the linear theory of elasticity. The effects of these initial stresses on the natural and forced vibrations around the hole within a plate-strip under additional bending load are investigated in the framework of the Three-Dimensional Linearized Theory of Elasticity (TDLTE) under the plane strain state, and the solutions of the considered boundary value problems are solved numerically by using the finite elements method. This paper shows that the influence of the plate's own weight has an important role on the dynamic analysis around the circular hole within a plate-strip. [ABSTRACT FROM AUTHOR]

In this study, the angle of twist of axially layered functionally graded circular hollow shafts subjected to a twisting torque at the free end was analyzed under clamped-free boundary conditions using finite element software ANSYS. The hollow shafts were made using three layers including various mixtures of ceramic and metal materials. Layer locations on the shafts were performed using L9 orthogonal array based on Taguchi Method. The layer combination with optimum levels was obtained using analysis of the signal-to-noise (S/N) ratio. Significant layers and their percent effects on the angles of twist were analyzed using analysis of variance (ANOVA). According to results obtained, the increase of the ceramic material in layers leads to the decrease of the angle of twist of the beams. The most meaningful layers on response were obtained as first layer with 52.83% effect ratio, second layer with 29.41% effect ratio, and third layer with 17.76% effect ratio. [ABSTRACT FROM AUTHOR]

The American ACI 307 design code imposes the use of diagonal rebars at the corners of flue gas inlet regions of reinforced concrete chimneys for mitigating cracks. There is currently no Turkish reinforced concrete design code in effect and the most commonly used chimney construction method is the slip form system. The diagonal rebars impose a difficulty in the construction of the slip form system due to the fact that they cross the line of action of the vertical support elements. In this study, the use of vertical and horizontal corner rebars with similar length and diameter was proposed as an alternative to using diagonal rebars. A detailed finite element model was constructed for a reinforced concrete chimney with a height of 115 m and an opening with a width of 3.7 m and a height of 5.2 m. Nonlinear material models were used for the concrete and rebars. The concrete shell was modeled with hexahedral elements and the rebars were modeled with 2-node bar elements. The design wind loads of the chimney were applied as lateral loads in three different directions. Separate analyses were conducted such that the opening region was located in the tension, compression, and shear zones. The highest tension strains and crack formations were obtained for the case of the opening region in the tension zone. Yield strain limits of the corner rebars were exceeded for the cases of the opening region in the tension and compression zones. The alternative corner reinforcement configuration led to similar results in terms of the opening deformations, crack formations, and corner rebar strains when compared with the original diagonal rebars in all the analyses. It was concluded that the proposed alternative corner rebar configuration can be used in the slip form construction of reinforced concrete chimneys. [ABSTRACT FROM AUTHOR]

In this paper, continuous and discontinuous contact problems for an elastic layer loaded by symmetrical distributed loads whose lengths are 2a on an elastic semi-infinite plane is solved using finite element method. The elastic layer also subjected to uniform vertical body force because of effect of the gravity. Thickness in z direction is taken to be unit. It is assumed that the contact surfaces are frictionless, only normal tractions can be transmitted through the contact areas. The contact along the interface between elastic layer and half plane is continuous if the value of load factor is less than a critical value. In continuous and discontinuous contact cases, the stress distribution on the contact interface are plotted for different dimensionless quantities. The finite element model of the problem is constituted using ANSYS software and analysis of the problem is carried out. Finally, the results obtained from the finite element solution are verified by comprasion with the analytical results. [ABSTRACT FROM AUTHOR]

Due to in depth tunnel excavation, tensions in the soil are eased, causing elastic and plastic deformations in the area of tunnel and leading to surface settlement at the ground level. Currently, along with the use of numerical methods in analysis and design of engineering projects, it is known that this method has used extensively in the analysis of problems related to geotechnical engineering and tunneling. Selection of the appropriate parameters and soil model can have a significant impact on the results of numerical analysis. The Mohr-Coulomb elastic-plastic model (MC) is one of the most widely used models, used in cases evaluating the hardness of materials, independent of the surface tension. If the Mohr-Coulomb used for numerical modeling of tunnel where in-depth tunneling excavation is involved and where an increase in maximum ground surface settlement and decrease in the reliability of stability of tunnels can be seen, which may not be appropriate in some conditions. The more appropriate model should be used to solve this problem, one that can model the hardness of materials based on changes in the level of stress. In this study, the maximum ground surface settlement due to tunnel excavation, obtained from Mohr- Coulomb model was compared with those of Hardening Soil (HS) Model results. Therefore, the ground surface settlement because of an assumption tunnel in different depths was analyzed with Mohr-Coulomb and Hardening Soil models by using PLAXIS 2D. As a result of the analyzes, it is observed that as the depth of the tunnel increases, the settlements on the ground surface decrease according to Mohr-Coulomb and approach the real values. [ABSTRACT FROM AUTHOR]

An artificial bedrock as wave impeding barrier can be used in practical civil engineering applications as isolation measures to protect structures from strong vibrations transmitted through soft ground nearby high-speed railway track. This study focuses on mitigation of the effects of high speed trains inducued vibrations on the strucutres which are located near the track lines by installing wave impeding barriers. Extensive parametric studies on the screening performance of wave impeding barrier have been done for both active and passive isolation cases. [ABSTRACT FROM AUTHOR]

One of the major problems in hip replacement surgery is the hip replacement loosening. Hip replacement loosening occurs over time after the surgery and it is related to the discretization between the bone cement and prosthesis. The underlying factors of this situation are the stress occurring in the bone cement and the shape of the prosthesis. In this study, cortical and trabecular layers of the femur, bone cement and prosthesis were modeled. The models of bone cement and prosthesis were constructed parametrically and two different sinusoidal formed prostheses were developed unlike the former prostheses shapes. Analyses were conducted for these two different sinusoidal forms by using finite element method and optimization was conducted to obtain the appropriate prosthesis stem shape and bone cement thickness by using parametric modeling in finite element analyses. For finite element analyses and optimization, Ansys Workbench software was used and analyses were conducted for 316LS stainless steel material. Finally, the optimum prosthesis stem shape and bone cement thickness was determined by using the results of the analyses in the first stage. [ABSTRACT FROM AUTHOR]

The purpose of this study is to investigate the stresses occurred on hard and soft bones after recovering the deficiency caused by totally edentulous and damaged mandible by using abutments with different lengths and prosthesis filling material. Two different damaged parts of 2.5 and 4.5 mm in depth were created with the aid of Solidworks program on the right hand side of the mandible. Implants were then applied between the foremen channels. Later, the damaged models were recovered by abutment with different lengths as for the first method. Two models using abutment were, therefore, obtained for the damaged parts of 2.5 and 4.5 mm in depth. In the second method, for the same damaged cases, prosthesis filling material was used to recover deficiency keeping the abutment length constant. Finally, there were totally obtained 4 different damaged models of two fixed with abutment and two fixed with filling material and 1 undamaged model. At the second step of this study, the stress values were obtained on lower jaw bones by using finite element method under the maximum chewing force and compared to each other. The results showed that stress data obtained particularly on the soft and hard bones were distributed more uniformly on the damaged models fixed with prosthesis filling material compared to the damaged models recovered by abutment. Moreover, the stress values obtained for models fixed with different abutment length were rather high in comparison to those of the filling material application. [ABSTRACT FROM AUTHOR]

Main structures in the Islamic architecture are generally composed of different style mosques and complexes of buildings adjacent to mosques. Hence, these structures can be found in every ancient Islamic city. However, over the past years, these structures have had some damages and many historical mosques have been at risk due to static and dynamic effects. Thus, better understanding of their structural behaviors is crucially important in order to determine the protection requirements for these structures. Therefore, this study mainly focuses on the structural behaviors of Kara Mustafa Pasha Mosque in Merzifon, Amasya, Turkey. The main purpose of this paper is to investigate structural behaviors of the domed mosque and to determine the static and dynamic effects. For this purpose, Kara Mustafa Pasha Mosque has been numerically modeled and it has been analyzed by means of static and dynamic analyses methods. [ABSTRACT FROM AUTHOR]

Power transmission components, which is one of the vehicles axle shafts are exposed to different loads and Therefore, axle shafts that may occur in some damage and failures. In this study belong to a vehicle rear-wheel drive has been conducted on a broken axle. Macroscopic photographed axle shaft and fracture surfaces then a static analysis was conducted on the shaft using the finite element method. Von-Mises stress values was accepted in the analysis. The critical stress values were determined. Taken as a three-dimensional analysis, using ANSYS finite element program. [ABSTRACT FROM AUTHOR]

Many researchers investigated the behavior of surface foundations constructed on reinforced sand (Omar et al. 1993; Khing et al. 1993; Yetimoglu et al. 1994; Das ve Omar 1994; Adams & Collin 1997). However most of the problematic foundation soils are of cohesive nature. Therefore in this study the effect of reinforcing cohesive foundation soils was investigated. Normally the cohesive soil excavated would be replaced by a granular fill. This means that improvement will be obtained due to the geosynthetic reinforcement but also because of the soil exchange. In order to see the effect of geosynthetic reinforcement alone, in this study the backfill was considered to have the same properties as the natural cohesive soil. The foundation behavior is assessed using limit equilibrium and finite element method (FEM). In this study the finite element code, Plaxis was used. A parametric study was conducted. Safety factors were calculated by using the "Phi-c reduction" method in the finite element analyses. In the "Phi-c reduction" approach the shear strength parameters tanθand c of the soil are successively reduced until failure occurs. The soil was modeled as Mohr-Coulomb model and the reinforcement as a linear elastic material. In the analyses, no specific interaction model between soil and reinforcement was used. The analyses presented in this study involve strip foundations on clay soil. The problem was analyzed under plane strain condition. The material properties were chosen in accordance with those in the literature to represent a clay soil. The soil parameters adopted were: γ = 15 kN/m³; E = 25000 kPa (500 * c); ? = 0.30; Ş= 0°; ψ? = 0°and c = 100, 75, 50, 37.5, 25, 12.5 kN/m² . Footing thickness was chosen as 0.143 m and was placed directly on the surface without any embedment. Geosynthetic axial stiffness per unit width was selected as J=2000kN/m to represent a typical geogrid (Deb et. al. 2007). For the finite element analyses, vertical boundary was chosen to have only horizontal fixity and bottom boundary has both horizontal and vertical fixity. The size of the finite element mesh used was the same for all the analyses. It was chosen to be large enough to reduce the boundary effects to a negligible level. Factor of Safety (GS) for bearing capacities of unreinforced soil were calculated first by Limit Equilibrium analysis and then by FEM. The footing width (B=2.5, 5, 10 and 20 m), cohesion of the foundation soil (c=50 and 100 kPa), and surcharge load on footing (100 and 200 kPa) were varied to assess their influence on the safety factor of the shallow foundation. A good agreement was achieved between bearing capacity calculated using limit equilibrium approaches and finite element solutions. The finite element analysis gave factor of safety values directly proportional to cohesion of the clay soil as expected. In order to investigate the influence of the reinforcement on the factor of safety, a parametric study was conducted using different reinforcement configurations. Number of reinforcement layers, depth of the first reinforcement, vertical spacing of reinforcement layers, width of reinforcements and cohesion values of soil were chosen as variables in the analyses. Results obtained are summarized below: •As the number of reinforcement layer increases (from one to six), the safety factor increases as well. Regardless of total number of reinforcement layers, the foundation width did not have a significant effect on the bearing capacity. •The depth of the first reinforcement varied between 0.05B and 0.7B. The most efficient initial reinforcement depth was found as 0.4B. •The vertical spacing between horizontal reinforcement layers (H) were taken as 0.025B, 0.05B and 0.1B. When six reinforcement layers were used, increase in the factor of safety values were calculated as: 7.5%, 12% and 17% for H/B values of 0.025, 0.05 and 0.1 respectively. •The reinforcement lengths analyzed were L=B; L=2B; L=3B; L=4B and L=5B. The increase in bearing capacity after a length of L=3B was negligible. •BCR and effective reinforcement depth were not affected when cohesion of the soil changed. [ABSTRACT FROM AUTHOR]

In this study, the failure analysis and failure zone expansion are numerically investigated in the uni-directional carbon fiber reinforced epoxy matrix resin laminated composite plates. The solution is performed with finite element methods by using ANSYS software. The loads, which are caused failure, are applied transversally to laminae plane and are increased from initial failure of the plate as 10-4 MPa at each load step. The initial failure loads are found by using Tsai - Wu failure theory, which is used for composites. The initial failure loads and failure zone expansion are obtained for fiber reinforcement angle, laminae configuration and support type variations and the results are presented with graphs. The results of conclusions, it is seen that the initial failure loads and expansion of failure zone are varied with laminae configurations and fiber reinforcement angle. [ABSTRACT FROM AUTHOR]

In this study, the failure analysis on the single lap bonded joint, which is used for joined two composite plates each other with adhesive, is investigated experimentally and numerically. In the joint, the epoxy resin is used for adhesive and the four layered carbon fiber reinforced epoxy matrix resin composite plates are used for adherent. Numerical study is performed in the ANSYS software which is used finite element method for solution. For obtained numerical failure loads, the progressive failure analysis is used with material property degradation rules. In the failure analysis the Hashin Failure Criterion is used for composite plates and the Maximum Principal Stress failure criterion is used for adhesive. The effects of the adhesive thickness overlap lengths and plate weight on the joint strength is investigated with numerically. As a result it is seen that the failure loads is affected the bond face area. The results are presented with graphs and tables. [ABSTRACT FROM AUTHOR]

In this study, the major aim is to investigate change effects of fiber orientation angles on the failure loads and failure modes for the pin jointed laminated composite plates. In the analysis, laminated composite plates with epoxy matrix resin reinforced unidirectional carbon fibers are used. The ply arrangements are chosen [θ0]4 and θ; fiber reinforced angle changes from 00 to 900 with 150 increments. The failure load and failure mode are analyzed experimentally and numerically. In the numerical analysis Ansys program is used. In the program, material properties are degraded using APDL code which is written for progressive failure analysis and contains Hashin failure criteria for laminated composite plates. In the experimental study, the maximum failure load for [150]4 laminae cofiguration, 749.917 N and minimum failure load for [600]4, 467.483 N laminae configuration are obtained. A good agreement between experimental and numerical solution is obtained. [ABSTRACT FROM AUTHOR]

In this study, the major aim is to investigate change effects of fiber orientation angles on the failure loads and failure modes for the pin jointed laminated composite plates. In the analysis, laminated composite plates with epoxy matrix resin reinforced unidirectional carbon fibers are used. The ply arrangements are chosen [θ°]4 and θ; fiber reinforced angle changes from 0° to 90° with 150 increments. The failure load and failure mode are analyzed experimentally and numerically. In the numerical analysis Ansys program is used. In the program, material properties are degraded using APDL code which is written for progressive failure analysis and contains Hashin failure criteria for laminated composite plates. In the experimental study, the maximum failure load for [15°]4 laminae cofiguration, 749.917 N and minimum failure load for [60°]4, 467.483 N laminae configuration are obtained. A good agreement between experimental and numerical solution is obtained. [ABSTRACT FROM AUTHOR]

In this paper, it is carried out the spread of plastic zones and the stress analysis at the composite plates with laminated thermoplastic (Polyvinyl Chloride) subsisting an elliptic hole in the middle part. The composite plates with steel fiber reinforcement of woven-shaped consist of four orthotropic layers bonded symmetrically in the form of [θ0-θ0]². The plates are subjected to uniformly distributed vertical loads. Loading is realized by iterations number of 25, 50, 75 and 100 by increments 0.0001 MPa by starting from the yielding point of plate for the chosen each reinforcement angle. According to the load steps and the different reinforcement angles, the values of the plastic stresses occurring in the composite plates are obtained by Finite Element Method. The obtained results present that the plastic zones in the plate appear in the lower and upper surfaces but not in the intermediate surfaces. It is also observed that the stress components at the intermediate layers are less than that of the lower and upper surfaces and the plastic stress components increase depending on the iteration number. [ABSTRACT FROM AUTHOR]

In this study, elastic-plastic stress analysis is performed in thermoplastic plate, which has symmetric and antisymmetric bonded laminated, with circular or square hole in the centre of plate. Elastic-plastic stress analysis is carried out on the laminated composite plate by using finite element method. The finite element package program ANSYS is used to perform the numerical analysis using eight node layered shell elements. In the analysis, the loads are applied transversally and plate edges are simply supported. Loading is gradually increased from zero to yield point of the plate as 0.0001 MPa at each load steps. The residual stresses are calculated for yield load +100 load steps and their expansion is investigated with +50, +100 and +150 load steps. The maximum residual stress at upper and lower surfaces of plate with different fiber orientations is found. The results of the residual stress are compared with other plates having square and circular holes. It is seen that the difference between yield loads and residual stress values of composite plates with square and circular hole is minor and plastic zones and residual stress values of the composite plate are increased by increasing transverse loads. [ABSTRACT FROM AUTHOR]

In this study elastic - plastic stress analysis is examined in a laminated thermoplastic composite plates under transverse loading conditions. For solving problem ANSYS program,which is used finite element method, is used. The effect of ply array, fiber orientation angle, supported type and plate dimension variation on elastic - plastic and residual stresses of laminated thermoplastic composite plates are investigated. Elastic-plastic analysis is made three steps. In the first step of the analysis the yielding loads are finding each plate and in the second step elastic-plastic stresses are obtained from yield load + 0.01 MPa load increment for each plate. The last step is made for obtained residual stresses and the load on the plate is removed. Obtained elastic-plastic and residual stresses are illustrated graphs in this study. [ABSTRACT FROM AUTHOR]