Finite Element Package Program Research Articles

Effects of translaminar edge crack and fiber angle on fracture toughness and crack propagation behaviors of laminated carbon fiber composites

Abstract In this study, the translaminar fracture toughness of carbon fiber laminated composites with different layer sequences was investigated experimentally and numerically for different crack directions. In the numerical study, first of all, the critical stress intensity factor was determined by using the M-integral method. Three-dimensional model and M-integral analysis were achieved in the ANSYS finite element package program. The non-local stress fracture criterion was used to in order to find failure curves of the materials. Then, in order to find the crack propagation directions numerically, the solid model was transferred to the LS-DYNA program and progressive failure analysis was performed. Fracture toughness decreased by 9.92 % with the change of crack angle from 15° to 90°. As the fiber angle changed from 0° to 45°, it decreased by 9.17 %. The biggest error between the experimental and numerical study results was found at α = 45°, with a rate of 12.3 %.

Experimental and numerical investigation of patch effect on the bending behavior for hat-shaped carbon fiber composite beams

Abstract In this study, reinforced composite panels with hat-shaped profile were produced from woven carbon fiber fabrics by vacuum infusion method. Holes were drilled on the crown surface of these panels and repaired with composite patches. The mechanical behavior was examined by performing a three-point bending test on the obtained patched and unpatched specimens. The contribution of the repair to the failure load of the damaged specimens under bending load has been clearly determined. In the numerical part, Hashin damage criterion was used for the beginning of damage. For damage progression, both Continuum Damage Mechanics and Material Property Degradation methods were preferred and compared. In the analysis carried out using the finite element package program Workbench, the cohesive zone model (CZM) was added to the model and its effect on the damage behavior and load of the composite structure was determined. As a result of the experiments and analyses, it was seen that the maximum contact force of the specimens under the bending load decreased by 29.8 % by increasing the number of holes on the specimen surface from 1 to 3. The maximum contact force was determined to increase by 18.52 % due to repairing the three-hole specimens with a patch.

Strength Comparison of Swing Tower Designs with Finite Element Method in Backhoe Loaders

Backhoe-Loader construction machines are exposed to several different loads within the scope of their usage areas. The degree of freedom of the attachment is one of the elements that ensures the functionality of the excavating zone. The movement of the attachment on the horizontal plane is provided with hydraulic cylinders. The forces and moments that comes from the attachment area are transferred directly to the upper chassis. It is critical that the swing tower located between the upper chassis and the attachment, can withstand these transferred loads. In this study, static structural analysis of different designs of the swing tower in the attachment area for HİDROMEK backhoe-loader machines was carried out with the finite element package program MSC Marc. The forces and moments that the HİDROMEK construction machine is exposed to due to working conditions were evaluated and applied as input in the analysis. The accuracy of the analysis method was verified by the strain gauge test performed on a model selected from the designs examined. As a result of the study; the models were compared in terms of strength, and the effects of the changes made on the designs on the strength were interpreted.

Numerical investigation of the effect of minaret height on its dynamic characteristics

Minarets are structures that have an important place in Islamic architecture. Although these structures have a long, thin and delicate appearance, they can be constructed in different cross-sections and heights. Due to their geometry, minarets can be damaged under earthquake and wind loads. In order to minimize the possibility of damage to these structures, they must be constructed with suitable geometry and materials. In this study, the effect of minaret height on dynamic characteristics (natural frequency and mode shape) was investigated numerically. For numerical application, 19 different minarets with heights ranging from 13.5 m to 33.75 m were modeled in the ANSYS finite element package program. It is assumed that the minarets have as masonry and the base of the minaret was fixed support to the soil. These minarets were evaluated in terms of natural frequency, mode shape and modal mass participation ratios by performing modal analyses. In addition, an equation has been derived that can predict the first natural frequency of the minaret depending on its height.

Experimental and numerical determination of interlayer shear strength of glass fiber-reinforced epoxy composites

This study aims to produce glass fiber composite plates by vacuum infusion method and to determine the interlaminar shear strength (ILSS) under the short beam test. For this purpose, composite plates were produced under the effect of vacuum and temperature by adding glass fiber layers on a flat vacuum table. Short beam tests were carried out on the obtained laminated composite plates and the interlayer shear strength, which is generally characterized by delamination damage, was investigated. In the numerical part, the tests were modeled using the LS-DYNA finite element package program, and the Hashin damage criterion-based material model was used to see the damages that occurred in the composite structure after the tests.

Finite Element Analysis for the Static Response of Functionally Graded Porous Sandwich Beams

In this paper, the finite element method is used to analyze the static response of the functionally graded porous (FGP) sandwich beams subjected to uniformly distributed loads along the beam span. The core of the beam is made up of functionally graded porous material while the top and bottom layers are made up of isotropic homogenous materials. Uniform distribution and symmetric distribution of pores are used as two different types of porous material. Shear deformation is considered in the analysis by utilizing BEAM189 in ANSYS which is a finite element package program. This element is based on the first-order shear deformation theory. The influence of porosity coefficient, boundary conditions, and type of the porous material on the static response of the considered structures is presented in detail. The results demonstrate that the porosity coefficient has an important impact on the static response of the FGP sandwich beams.

Investigation of the effect of modal analysis correlation on actuator/sensor positions for plate structures

In this study, a mode combination approach is proposed to place actuator/sensor pairs according to the experimental modal analysis results. The method is carried out by combining modes using the weighting coefficients with a finite element package program. First, this approach is applied to four different structures presented in the previous works in literature to compare and verify. Our results demonstrate that the determined best locations overlap well with the published results. Then, this combination approach is applied to the steel plate with bolt connections on four sides to determine actuator/sensor (a/s) pairs’ placement accuracy, which is directly related to experimental/numerical modal correlation. For this purpose, three different cases varying by weighting coefficients are determined to show the modal correlation's effectiveness. Finally, the possible best a/s positions for three cases are compared. In conclusion, the presented mode combination approach is a fast and practical solution for determining a/s pairs’ placement, and the experimental/numerical modal analysis correlation directly affects the placement's success.

Effect of repair parameters on composite plates under low velocity impact

In this study, the impact behavior of patch-repaired layered composite plates under low velocity impact loads was numerically investigated. For this purpose, layered composite plates with holes with different geometries in the middle were repaired with patches using various adhesives. Impact behavior of the composite material was investigated by dropping the strikers with different speeds on the repaired composite plate. Layered composite plate was used as the sheet and patch material, and the orientation angles are [0 ° / 45 ° / 45 ° / 0 °] for the plate and [0 ° / 45 °] for the patch. ANSYS Ls-Dyna finite element package program was used for three dimensional modelling and solution. Therefore, the effects of variables such as striker, adhesive, plate and patch on the impact behavior of layered composite material were investigated for different boundary conditions. It has been determined that the hexagonal patch type performs better than other patch geometries.

Finite element model updating of masonry minarets by using operational modal analysis method

In this paper, finite element model (FEM) updating of masonry minarets was conducted by using dynamic characteristics obtained from Operational Modal Analysis (OMA). For numerical application, Mustafa Şahin mosque minaret in Turkey’s Elazığ province was selected. In the finite element modelling, structure-foundation-soil interaction was considered. Soil, foundation and structure domains were assumed to be linearly elastic. The masses of foundation and soil were ignored. The FEM updating was performed by comparing the frequencies and mode shapes obtained from the FEM solutions with those of the experimental (OMA) method. The compatibility of numerical and experimental modes was controlled by the Modal Assurance Criterion (MAC) values. The FEM solutions were obtained by using ANSYS finite element package program.

Consolidation settlement calculation and examination of the foundation settlements with finite elements method, example of Batman city Gültepe bridge

In this study, geological and geotechnical studies were carried out on the soil of a bridge built in 2015 in the Gültepe District of Batman City, located in southeastern Turkey, to perform the foundation settlement calculation. For this purpose, four foundation boreholes were drilled to determine the engineering parameters of the soil, and triaxial pressure and consolidation tests were carried out on the obtained samples. The consolidation settlement calculation was made in accordance with these parameters. Using the same data, numerical analysis was performed with PLAXIS V.8.2 (Finite Element Code for Soil and Rock Analyses), a two-dimensional finite element package program. The consolidation settlement value was calculated by performing dynamic analysis based on time in the computer software. The settlement value was determined to be 1.70 cm after the analysis, and it was evaluated by correlating with the consolidation settlement analysis results made according to Bowles (1988). Consolidation settlement calculations and finite element package program analyses gave similar results. We observed liquefaction risk and settlements in the structures with shallow foundations in the residential zone near the study area since the soils in the study area consist of silty sand of 5-10 meters and have groundwater. The Bored Pile technique, which is one of the soil improvement methods, was applied and discussed in order to determine the geological problems in the study field.

Effect of fiber orientation on interfacial fracture toughness for adhesively bonded composite plates

In this study, interfacial fracture toughness was investigated experimentally and numerically in laminated composite plates with different fiber reinforcement angles bonded with adhesive. The composite plates are four-layered and the layer sequence is [0o/θ]s. DCB test was applied to composite plates reinforced with epoxy resin matrix and unidirectional carbon fiber. The experimental sample model for the DCB test was made using the ANSYS finite element package program. In the numerical study, four layered composites were prepared in three dimensions. Under critical displacement value; mode I fracture toughness at the crack tip was calculated using VCC (virtual crack closure) technique. Numerical values consistent with experimental results have presented in graphical forms. At 60o and 75° the greatest fracture toughness was obtained. In addition, numerical results have shown that fiber orientation prevents the uniform distribution of stress on the interface crack tip and causes stress accumulation, especially at the edge of the plate.

Finite element modeling of RC gable roof beams with openings of different sizes and configurations

This paper presents numerical simulation performed by using a commercial finite element program package of ABAQUS/CAE version 2018 to investigate the flexural behavior of 13 existing simply supported reinforced concrete (RC) gable roof beams including openings of different size and configurations subjected to monotonic loads. Since insertion of openings in a RC beams result in complicated behavior due to geometric discontinuity and discontinuities or disturbances in the normal flow of stresses therefore, this study aims to propose a numerical model, including a reliable finite element model technique and constitutive material models, to simulate nonlinear behavior of such beams. Comparisons between numerical and experimental models in terms of load-deflection and crack patterns are presented and good agreement is shown. The average ratio of ultimate loads and deflection of numerical models to that of the experimental tested beams, was 1.04 and 0.98, respectively. Therefore, finite element analysis can be considered a preferable and reliable technique to simulate non-linear behavior of RC gable roof beams with openings, from the view point of complicated, difficulty, time saving, human effort and budget.

Simulation two storey house of masonry wall under the earthquake load

The masonry wall building systems have high sensitivity against earthquakes and the fact that this system of construction is widespread in Iraq, especially condominiums. Iraq subjected to many earthquakes in recent years and is expected to be subjected to more intensities of earthquakes in the future engendered an urgent need to investigate the behavior of this type of construction under the influence of earthquakes. The analysis of two-storey house in this research paper was performed by the finite element package program ABAQUS. Model simulation with dimensions (5 * 20 m) from the common one and two-storey house models in Iraq. The compressive strength of bricks (17MPa) type A and compressive strength of mortar(15MPa) with mixing ratio 1:3 was used to represented of the properties of construction materials in Iraq. The nonlinearity behavior of the materials is considered in this research paper. The model is subjected to PGA(0.5g) from EL-Centro Earthquake (1940 N-S ) as input ground motion to determine its seismic performance compared the maximum displacement, drift and base shear for models with the seismic demand of Iraq. Through the analysis of the results, the models proved efficient and stable against the effect of earthquakes, especially when the load applied in the Z long direction, more than the load applied in the X short direction for all models

Fracture toughness of woven glass and carbon reinforced hybrid and non‐hybrid composite plates

The fracture toughness and strength of materials are adversely affected by the cracks in the materials, which can be induced during manufacturing, assembly, and usage. In this study, the effect of crack length and crack location on the fracture toughness of woven glass and carbon reinforced hybrid and non‐hybrid composite plates were investigated experimentally and numerically. For this purpose, glass/epoxy (G8), and carbon/epoxy (C8) non‐hybrid composite plates and glass‐carbon/epoxy (G2C4G2), and carbon‐glass/epoxy (C2G4C2) hybrid composite plates were produced by using hand lay‐up method. The fracture toughness of hybrid and non‐hybrid composite plates having three different crack locations as single edge crack (SEC), center crack (CC), and double edge crack (DEC) with different crack lengths were obtained by determining failure loads under tensile loading. The ANSYS finite element package program was used in order to determine the fracture toughness of hybrid and non‐hybrid composites by means of J‐Integral methods. The results showed that the highest and the lowest fracture toughness values were obtained in the specimens with SEC and CC, respectively. POLYM. COMPOS., 39:783–793, 2018. © 2016 Society of Plastics Engineers

A new box iterative method for a class of nonlinear interface problems with application in solving Poisson–Boltzmann equation

In this paper, a new box iterative method for solving a class of nonlinear interface problems is proposed by intermixing linear and nonlinear boundary value problems based on a special seven-overlapped-boxes partition. It is then applied to the construction of a new finite element and finite difference hybrid scheme for solving the Poisson–Boltzmann equation (PBE) — a second order nonlinear elliptic interface problem for computing electrostatics of an ionic solvated protein. Furthermore, a modified Newton minimization algorithm accelerated by a multigrid preconditioned conjugate gradient method is presented to efficiently solve each involved nonlinear boundary value problem. In addition, the analytical solution of a Poisson dielectric test model with a spherical solute region containing multiple charges is expressed in a simple series of Legendre polynomials, resulting in a new PBE test model that works for a large number of point charges. The new PBE hybrid solver is programmed as a software package, and numerically validated on the new PBE test model with 892 point charges. It is also compared to a commonly used finite difference scheme in the accuracy of computing solution and electrostatic free energy for three proteins with up to 2124 atomic charges. Numerical results on six proteins demonstrate its high performance in comparison to the PBE finite element program package reported in Xie (2014).

A numerical investigation of dynamic plastic buckling behaviour of thin-walled cylindrical structures with several geometries

In this study dynamic buckling behaviors of an aluminum alloy cylindrical shell with axial linear variable thickness, discontinuity and conical shaped have been numerically investigated for high velocity impact by means of finite element method. The validation of finite element model was provided by the results of previous studies in literature. Throughout study commerce finite element package program LS-DYNA3D was used and all simulations were fulfilled as explicitly. According to results obtained, the minor changes in the geometry are able to convert the dynamic plastic buckling into dynamic progressive buckling behavior. This study indicates that which of the dynamic buckling or progressive buckling mechanism will be dominant is sensitive to geometrical properties for cylindrical aluminum alloy shells under the high velocity impact.

New solution decomposition and minimization schemes for Poisson–Boltzmann equation in calculation of biomolecular electrostatics

The Poisson–Boltzmann equation (PBE) is one widely-used implicit solvent continuum model in the calculation of electrostatic potential energy for biomolecules in ionic solvent, but its numerical solution remains a challenge due to its strong singularity and nonlinearity caused by its singular distribution source terms and exponential nonlinear terms. To effectively deal with such a challenge, in this paper, new solution decomposition and minimization schemes are proposed, together with a new PBE analysis on solution existence and uniqueness. Moreover, a PBE finite element program package is developed in Python based on the FEniCS program library and GAMer, a molecular surface and volumetric mesh generation program package. Numerical tests on proteins and a nonlinear Born ball model with an analytical solution validate the new solution decomposition and minimization schemes, and demonstrate the effectiveness and efficiency of the new PBE finite element program package.

Piezoelektrik Bir Motorun ANSYS'de Dinamik Analizi

In this study, Piezolegs-LL1011A which is linear piezoelectric motor type has been selected as a model. After modelling has been done of this motor, modal and harmonic analysis of same motor have been obtained with finite element package program ANSYS. As a result of these analysis, natural frequency values have been obtained of Piezolegs motor. An appropriate frequency range for motion of drive tip is obtained for harmonic analysis. In according to applied forces, harmonic analysis is done and drive tip motion of motor is observed. © Afyon Kocatepe Universitesi

Analytical investigation of a three-dimensional FRP-retrofitted reinforced concrete structure's behaviour under earthquake load effect in ANSYS program

Abstract. In this study, a 1:3 scaled, three-storey, FRP (Fiber Reinforced Polymer) retrofitted reinforced concrete model structure whose behaviour and crack development were identified experimentally in the laboratory was investigated analytically. Determination of structural behaviour under earthquake load is only possible in a laboratory environment with a specific scale, as carrying out structural experiments is difficult due to the evaluation of increased parameter numbers and because it requires an expensive laboratory setup. In an analytical study, structure was modelled using ANSYS Finite Element Package Program (2007), and its behaviour and crack development were revealed. When experimental difficulties are taken into consideration, analytical investigation of structure behaviour is more economic and much faster. At the end of the study, experimental results of structural behaviour and crack development were compared with analytical data. It was concluded that in a model structure retrofitted with FRP, the behaviour and cracking model can be determined without testing by determining the reasons for the points where analytical results are not converged with experimental data. Better understanding of structural behaviour is analytically enabled with the study.

Experimental Study on the Ultimate Bearing Capacity of Partially Overlapped CHS-to-SHS Welded N-Joints

This paper presents the experimental and numerical results of the ultimate bearing capacity of partially overlapped tubular N-joints, which have circular hollow section (CHS) brace members welded to a square hollow section (SHS) chord member. Two partially overlapped N-joints were tested to failure under overlapping brace axial loading and chord axial loading. The failure mode of specimen N1 was the overlapping brace local bucking, and the failure mode of specimen N2 was the chord face plastification with chord side wall buckling. Meanwhile, weld fracture occurred on both specimens. Then, making use of finite element package program ANSYS, in which twenty nodes solid element was employed and the weld was simulated, elastic-plastic large deflection finite element analysis of the experimental joints was conducted. The experimental data were compared with the results acquired by finite element analysis and it was proved that ANSYS is feasible to simulate the connecting weld and analyze the static behavior of partially overlapped CHS-to-SHS welded N-joints.