Thermal Elastic-plastic Stress Analysis Research Articles

Development of Al/Cu Dissimilar Joint by New Friction Welding Method

Aluminum alloy / pure copper joint has been tried to produce by the conventional welding method. However, some combination of the joints could not show high joint efficiency. The reason for this is considered to the formation of the intermetallic compound and involvement of the metal flake of joint specimens. A2017 aluminum alloy/Cu joint was examined by the new friction welding technology which has the intermediate material for friction between joint specimens. Furthermore, thermal elastic-plastic stress analysis was conducted for searching the optimum welding condition. The results are as follows. (1) 60% joint efficiency larger than that in the conventional process was obtained. (2) Intermetallic compound and involvement of the metal flake are not recognized by a micro inspection such as SEM. (3) Increase of oxygen content is recognized in Al side near the interface, however, it occurred during upset stage because oxygen content does not increase in Cu side. (4) The precise position of welding interface could be determined from the change of oxygen content near interface. (5) For producing sound joint of this combination of the materials, it is important that both materials are plastically deformed by maintaining strength balance between Al and Cu near the interface.

Elastic–plastic thermal stress analysis in a thermoplastic composite disc applied linear temperature loads via FEM

The aim of this study is to obtain thermal stresses in a thermoplastic composite disc unidirectionally reinforced by steel fibers. Finite element method was used to calculate the thermal elastic and elastic-plastic stress distributions within the composite disc. Therefore, the solution was carried out using the ANSYS software. The temperature loading was chosen so as to vary linearly from inner surface to outer surface along the radial sections of the disc. Linear thermal loads were selected as to differ from each other. They were also adjusted from 90 to 130^oC. Thermal stresses were formed within the disc by the linear temperature loads due to its having different thermal expansion coefficients in radial and tangential directions. In line with the thermal analysis results, the magnitudes of the tangential stress components for both elastic and elastic-plastic solutions were above the radial stress components. In addition, the residual stress components were also calculated using both elastic and elastic-plastic solution results. The results obtained pointed out that the magnitudes and distributions of the thermal stresses and residual stresses were greatly influenced by the increase in linear temperature loads.

Predicting Locations of Defects in the Solidification Process for Large-Scale Cast Steel

The large-scale cast steel has been used in broad fields of industries, such as power generation, construction, vessels, and automobiles. In the solidification process of a hummer used for press machine, for example, sometimes defects such as shrinkage cavity, segregation and cracks appear at hummer’s surface. Shrinkage cavity and segregation can be predicted by performing non-steady state heat transfer analysis; and therefore such two types of defects can be eliminated by using chills which control solidification process. However, uneven cooling rates at different regions of the large-scale cast steel generate thermal stresses, which cause solidification cracks, between the chills. For causing those cracks, thermal stress may be important; however, there have been few studies for this thermal stress analysis. In this study, a three dimensional thermal elastic-plastic stress analysis has been performed by using finite element method in connection with three dimensional non-steady state heat transfer analysis, including interaction between the temperature and stress field. The results provide further understanding of the observed solidification crack failure for large-scale cast steel.

Elastic-plastic thermal stress analysis of an aluminum composite disc under parabolic thermal load distribution

An elastic-plastic thermal stress analysis was carried out on an orthotropic aluminum metal matrix composite disc with a hole by using an analytical solution. The thermal load distribution was chosen to vary parabolically from inner surface to outer surface. An aluminum composite disc reinforced curvilinearly by steel fibers was produced under hydraulic press. The mechanical properties of the composite disc were obtained from experiments by using strain gauges. A computer program was developed to calculate the thermal stresses under a parabolic temperature from inner surface to outer surface. The material was assumed to be non-linear hardening. The elastic-plastic solution was performed for the plastic region expanded around the inner surface by an analytical method. The magnitude of the tangential stress component for elastic and elastic-plastic was higher than the magnitude of the radial stress component. Besides, the tangential stress component was compressive on the inner surface and tensile on the outer surface. The magnitude of the tangential residual stress component was the highest on the inner surface of the composite disc. The plastic region began at the inner surface of disc.

Thermal Elastic-Plastic Stress Analysis of an Aluminium Composite Disc under Linearly Decreasing Thermal Loading

In this study, an elastic-plastic thermal stress analysis of an orthotropic aluminium metal matrix composite disc with a hole has been investigated analytically for non-linear hardening material behaviour. The aluminium composite disc reinforced curvilinearly by steel fibres is produced under hydraulic press. The mechanical properties of the composite disc are obtained by tests. A computer program is developed to calculate the thermal stresses under a linearly decreasing temperature from inner surface to outer surface. Elastic, elastic-plastic and residual thermal stress distributions are obtained analytically from inner surface to outer surface and they are presented in tables and Fig. s. The elastic-plastic solution is performed for the plastic region expanding around the inner surface. The magnitude of the tangential stress component has been found out in this study to be higher than the magnitude of the radial stress component. Besides, the tangential stress component is compressive at the inner surface and tensile at the outer surface. The magnitude of the tangential residual stress component is the highest at the inner surface of the composite disc.

Thermal stress analysis of 1 MW gyrotron collector

During 2004 and 2005, collectors on three of the gyrotrons used at DIII-D failed due to stress cracks. In order to investigate reasons for these failures, a nonlinear elastic plastic thermal stress analysis of the collector/design was undertaken. The thermal stress analysis results indicated that the effective strain for oxygen free high conductivity copper material under the operating conditions limited the cycle life of the collector due to fatigue, resulting in failures. The desired service life of more than 10 5 thermal cycles can be obtained by: (1) operational changes, such as increasing the frequency and amplitude of sweeping to reduce the effective heat flux, (2) design changes, such as: increasing the height and/or diameter of collector, enhancing the heat transfer coefficient by roughening the coolant channel walls, or (3) changing the material of the collector to dispersion strengthened copper such as Glidcop. The analysis and conclusions are presented.

An Elastic-Plastic Thermal Stress Analysis of Cross-ply and Angle-ply Aluminum Metal-matrix Composite Arches

A thermal elastic-plastic stress analysis is carried out on cross-ply and angle-ply steel fiber reinforced aluminum metal-matrix laminated composite arch under uniform temperature distribution. The composite material is assumed to be strain hardening linearly and consists of 4, 8, 12, and 16 layers bonded symmetrically and anti-symmetrically. First yielding temperature, thermal residual stresses, and the distribution of these stresses under thermal loading are investigated by using the finite element method (FEM). The effects of orientation angle, layer number, and stacking sequence on the residual stresses are analyzed. The magnitudes of residual stress components increase gradually depending on the temperature increment. It is found that the orientation angle affects the yield point and the intensity of residual stresses significantly, while the layer number and stacking sequence result in slight differences.

Thermal Residual Stresses in Simply Supported Thermoplastic Laminated Plates under a Parabolic Temperature Distribution

In the present study, a thermal elastic-plastic stress analysis is carried out on simply supported symmetric cross-ply [0/90]2 and angle-ply [30/30]2, [45/45]2, and [60/60]2 thermoplastic laminated plates. The temperature changes parabolically along the thickness of the plates. It is T0 and T0 at the upper and lower surfaces, respectively. The composite material is assumed to be linear strain hardening. An analytical solution is performed for satisfying the thermal elastic-plastic stress-strain relationship and boundary conditions for small plastic deformations. The Tsai-Hill theory is used as a yield criterion. The elastic-plastic solution is carried out for small plastic deformations. The residual stress distributions along the thickness of the plates are obtained.

A finite element analysis technique for predicting as-sprayed residual stresses generated by the plasma spray coating process

It is essential to analyze the residual stresses during the deposition of plasma sprayed coatings since they adversely affect the coatings’ performance during their service. In this article, finite element coupled heat transfer and elastic–plastic thermal stress analysis using a general purpose commercial FEM software ANSYS (ANSYS Inc., Southpointe, PA, USA) are presented to simulate the in situ residual stress generation during plasma spraying of duplex thermal barrier coatings (TBCs). The complicated physical spray process was idealized and a multiple layer-by-layer coating structure was assumed. In the simulation, the geometry was updated layer by layer and results from the previous layer analysis, including temperature and displacement, were used as loads for the current layer analysis. The predicted specimen temperature and curvature agreed well with those experimentally measured by thermocouples and a specially designed laser-displacement-measurement system, respectively. A simple method by post-deposition treatment was also proposed to effectively reduce the residual stress level in the coated specimen, with the possibility of eliminating the residual stress.

Elasto-plastic Thermal Stress Analysis in Symmetric Thermoplastic Laminates

In this study, a thermal elastic–plastic stress analysis is carried out in steel fiber-reinforced symmetric thermoplastic laminated plates. The material is assumed to be strain-hardening. The orientation angles are chosen as, (0°/90°)s, (30°/30°)s, (45°/45°)s, (60°/60°)s, (15°/0°)s, (30°/0°)s, (45°/0°)s, (60°/0°)s, (75°/0°)s. The Tsai–Hill theory is used as a yield criterion in the solution. Temperature distribution is chosen as þT0 and T0 at the upper and lower surfaces, respectively. It is found that plastic yielding occurs at the same temperature; all the orientation angles and the plastic region expands the same at the same temperature.

Residual Stress Analysis in Symmetric Thermoplastic Laminated Plates Under Thermal Loads: Analytic Solution

In this paper, thermal elastic-plastic stress analysis is carried out on simply supported symmetric cross-ply [0°/90°]2 and angle-ply [15°/-15°]2, [30°/-30°]2,[45°/-45°]2,[60°/-60°]2 thermoplastic laminated plates under various temperature change through the thickness of plates. The plates are composed of four orthotropic layers bonded symmetrically. In the solution, a special computer program has been employed. The composite materials are assumed to be strain hardening. The Tsai-Hill Theory is used as a yield criterion. Residual stresses are determined in the symmetric cross-ply and angle-ply laminated plates for small deformations. The intensity of stress components in the symmetric cross-ply laminated plate is higher than in angle-ply laminated plate due to the differences among the stiffnesses of layers. Plastic yielding occurs in all the laminated plate at the same temperature.

An Elastic-Plastic Stress Analysis of Symmetric Aluminum Metal-Matrix Composite Laminated Plates under Thermal Loads

In this study, a thermal elastic-plastic stress analysis is carried out on symmetric cross-ply (0°/90°)2 and angle-ply (30°/30°)2, (45°/45°)2, (60°/60°)2 aluminum metal-matrix composite laminated plates. Temperature changes parabolically from T0 up to T0 along the thickness. It is zero on the middle axis. The composite material is assumed to be linear strain hardening. The Tsai-Hill Theory is used as a yield criterion. The elastic-plastic solution is carried out for small plastic deformations. The distributions residual stress components of σ x and σ y are illustrated along the thickness of the laminated plates. All the residual stress moments are in static balance with respect to middle plane of the laminates since they are symmetric in opposite signs.

Thermal Elastic–Plastic Stress Analysis of Aluminum Metal–Matrix Composite Laminated Plates Under a Parabollically Temperature Distribution

In this study, a thermal elastic–plastic stress analysis is carried out on steel-fiberreinforced aluminum metal–matrix composite laminated plates fixed at all edges. Temperature is chosen to vary parabollically. It is zero and T0 on the middle axis and at the upper–lower surfaces, respectively. The solution is executed for symmetric cross-ply (0° /90°)2 and angle-ply (30° / -30°)2, (45° / -45°)2, (60° / -60°)2 laminated plates. The elastic–plastic solution is carried out for small plastic deformations. The Tsai–Hill Theory is used as a yield criterion. Residual stress distributions along the thickness of the plates are obtained. All the residual stress components are in static balance with respect to middle plane of the laminates since they are symmetric in opposite signs.

Thermal Elastic-Plastic Stress Analysis of Symmetric Aluminum Metal-Matrix Composite Laminated Plates and Residual Stresses Under Thermal Loads Varying Linearly

This paper deals with elastic-plastic stress analysis of symmetric cross-ply [0/90]2 and angle-ply [30/30]2, [45/45]2, [60/60]2 aluminum metal-matrix laminated plates under thermal loads varying linearly along the thickness. The temperature is T0 at the upper and lower surfaces, respectively. The solution is performed for satisfying thermal elastic-plastic stress-strain relations and boundary conditions for small plastic deformations. Tsai-Hill Criterion is used as a yield criterion. Residual stresses distributions along the thickness of the plates are obtained. All the residual stress components are in static balance with respect to middle plane of the laminates since they are symmetric in opposite signs. The magnitude of the residual stress components is the highest at the upper and lower surfaces.

Thermal Elastic-Plastic Stress Analysis of Antisymmetric Aluminium Metal-Matrix Composite Laminated Plates Under Constant Temperature Change through the Thickness

In this paper, thermal elastic-plastic stress analysis is carried out on simply supported antisymmetric cross-ply [0°/90°]2 and angle-ply [30°/−30°]2, [45°/−45°]2, [60°/−60°]2, [15°/−15°]2, [15°/−30°]2, [15°/−45°]2, [15°/−60°]2 aluminium metal-matrix laminated plates under constant temperature change through the thickness of plates. The plates are composed of four orthotropic layers bonded antisymmetrically. In the solution, a special computer program has been employed. The composite materials are assumed to be perfectly plastic. Tsai-Hill Theory is used as a yield criterion. Plastic and residual stresses are determined in the antisymmetric cross-ply and angle-ply laminated plates for small deformations. The intensity of stress components in the antisymmetric cross-ply laminated plate is higher than in angle-ply laminated plate due to the differences among the stiffnesses of layers. Plastic yielding occurs in all the laminated plates at the same temperature.

Thermal Residual Stresses in Aluminum Metal-Matrix Antisymmetric Laminated Plates Under Uniform Temperature Distribution

Thermal stresses are of great importance in composite structures. In this investigation, a thermal elastic-plastic stress analysis is carried out in (0°/90°)2, (30°/−30°)2, (45°/−45°)2, (60°/−60°)2, (15°/−15°)2, (15°/30°)2, (15°/45°)2, (15°/60°)2 antisymmetric aluminum metal-matrix laminated plates. Temperature is chosen to be constant along the cross sections of the plates. The residual stress components of σ x, σ y and τ xy are illustrated in the layers of the laminated plates for different thermal loading. Elastic-plastic and residual stress components are given in tables. When the absolute value between the orientation angles of the layers is increased, the magnitude of the residual stress components becomes high. The strength of the laminated plates can be increased by using residual stresses. Tsai-Hill criterion is used as a yield criterion. Differential equations are solved numerically with a sufficiently large number of integration intervals of the temperature. The composite material is assumed to be linearly strain hardening.

THERMAL ELASTIC-PLASTIC STRESS ANALYSIS OF SYMMETRIC ALUMINUM METAL-MATRIX COMPOSITE LAMINATED PLATES UNDER LINEARLY DISTRIBUTED TEMPERATURE

In this study, thermal elastic-plastic stress analysis is carried out on simply supported symmetric cross-ply (0/90) 2 and angle-ply (30/ m 30) 2 , (45/ m 45) 2 , (60/ m 60) 2 aluminum metal-matrix laminated plates under a linear temperature distribution across the thickness of plates. The temperature distribution is chosen as T 0 and zero at the lower and upper surfaces, respectively. Tsai-Hill theory is used as a yield criterion. Differential equations are solved with a sufficiently large number of integration intervals of the temperature. The composite material is assumed to be strain hardening linearly. The magnitude of the residual stress components of σ x and σ y is the highest at the upper and lower surfaces. Plastic yielding occurs in all the laminated plates at the same temperature.

Thermal Stress Analysis and Residual Stresses in a Thermoplastic Composite Beam

In this study, an elastic-plastic thermal stress analysis is carried out on a steel fibre reinforced thermoplastic matrix composite beam. Temperature is chosen to vary linearly, that is zero and T0 at the upper and lower surfaces, respectively. The beam is fixed by two rigid planes at the ends. The solution is performed at 0,45, 60,75 and 90 orientation angles. Plastic yielding is not obtained for 30 orientation angle. The plastic region is expanded at the lower side of the beam. It is found that the intensity of the residual stress component of x and the equivalent plastic strain are maximum at the lower surface of the beam. The residual stress is found to be greatest for 0 orientation angle. The intensity of the equivalent plastic strain is the greatest for 45 orientation angle. In addition, for the same plastic distribution, the intensity of the transverse displacement is the largest for that orientation angle.

Elastic-plastic and residual stresses in symmetric thermoplastic laminated plates under a linear thermal loading

Thermal stresses are of great importance in composite structures. In this study, a thermal elastic-plastic stress analysis is carried out in (0°/90°) 2, (30°/−30°) 2, (45°/−45°) 2, (60°/−60°) 2 symmetric thermoplastic laminated plates. Temperature changes linearly along the cross sections of the plates. It is zero and T o at the upper and lower surfaces, respectively. The distribution of the residual stress components of σ x and σ y are illustrated along the cross sections of the laminated plates for different thermal loading. Elastic-plastic and residual stress components are given in the tables. The strength of the laminated plates may be increased by using residual stress. Tsai–Hill Criterion is used as a yield criterion. Differential equations are solved numerically with a sufficiently large number of integration intervals of the temperature. The composite material is assumed to be linear strain hardening.

Thermal Elastic-Plastic Stress Analysis in Simply Supported Thermoplastic Laminated Plates

In the present study, an analytical elasto-plastic stress analysis is carried out on symmetric cross-ply [0°/90°]2 and symmetric angle-ply [30°/-30°]2, [45°/-45°]2, [60°/-60°]2, thermoplastic laminated plates. Composite laminated plates are simply supported and subjected to constant temperature change through the thickness. The analytical solution is performed for satisfying thermoelastic-plastic stress-strain relations and boundary conditions for small plastic deformations. The composite materials are assumed to be linearly hardening. The Tsai-Hill theory is used as a yield criterion. Residual stress components (σ x) r and (σ y) r for cross-ply laminated plates have some magnitudes but (τ xy) r are zero. The intensity of residual stress components increase gradually depending on the temperature increment. For symmetric angle-ply laminated plates, all residual stresses are found zero.