scholarly journals A Nonlinear Analysis Interpretation of Off-Axis Test Results in Metal Matrix Composites

2020 ◽  
Vol 4 (3) ◽  
pp. 127
Author(s):  
Jalees Ahmad ◽  
Unni Santhosh ◽  
Swamy Chandu

A unit-cell based micromechanics approach is used to perform nonlinear finite element analyses of off-axis tensile tests on an SCS-6/Ti-6Al-4V composite. The results are used in predicting the global deformation response of the composite that includes the effect of fiber-matrix interface damage. The predictions are compared with laboratory test data of uniaxial off-axis specimens. Based on the comparison, it is found that the procedure effectively predicts global composite response with reasonable accuracy under a general multiaxial stress state.

2011 ◽  
Vol 105-107 ◽  
pp. 796-799
Author(s):  
Dan Li ◽  
Yu Ye Xu ◽  
Zheng He Qiu ◽  
Yong Lin Zheng

Nonlinear finite element analysis (FEA) for the torsion behavior of reinforced concrete '+'-shaped columns with various axial load ratios was carried out by the general software ANSYS. Then a comparison between the FEA calculations and the test results is made. The numerical examples show that: (1) the cracking torque and ultimate torque of reinforced concrete '+'-shaped columns under the combined actions of axial force and torque can be predicted with a reasonable accuracy. (2) the axial ratio has significant effects on the torsion behavior '+'-shaped columns. The cracking torque and ultimate torque of '+'-shaped columns increase with an increase of axial load ratio. Comparing with reinforced concrete '+'-shaped column with an axial load ratio of 0.063, the cracking torque and ultimate torque of reinforced concrete '+'-shaped columns with axial load ratios of 0.189 and 0.314 were increased by 28.3% and 71.9%, 79.4% and 96.0%, respectively.


Author(s):  
Jing Zhang ◽  
Hong-wei Guo ◽  
Juan Wu ◽  
Zi-ming Kou ◽  
Anders Eriksson

In view of the problems of low accuracy, small rotational angle, and large impact caused by flexure joints during the deployment process, an integrated flexure revolute (FR) joint for folding mechanisms was designed. The design was based on the method of compliance and stiffness ellipsoids, using a compliant dyad building block as its flexible unit. Using the single-point synthesis method, the parameterized model of the flexible unit was established to achieve a reasonable allocation of flexibility in different directions. Based on the single-parameter error analysis, two error models were established to evaluate the designed flexure joint. The rotational stiffness, the translational stiffness, and the maximum rotational angle of the joints were analyzed by nonlinear finite element analyses. The rotational angle of one joint can reach 25.5° in one direction. The rotational angle of the series FR joint can achieve 50° in one direction. Experiments on single and series flexure joints were carried out to verify the correctness of the design and analysis of the flexure joint.


2020 ◽  
pp. 136943322098166
Author(s):  
Shuhao Yin ◽  
Bin Rong ◽  
Lei Wang ◽  
Yiliang Sun ◽  
Wuchen Zhang ◽  
...  

This paper studies the shear performance of the connection with the external stiffening ring between the square steel tubular column and unequal-depth steel beams. Two specimens of interior column connections were tested under low cyclic loading. The deformation characteristics and failure modes exhibited by the test phenomena can be summarized as: (1) two specimens all exhibited shear deformation in steel tube web of the panel zone and (2) weld fracture in the panel zone and plastic hinge failure at beam end were observed. Besides, load-displacement behaviors and strain distributions have been also discussed. The nonlinear finite element models were developed to verify the test results. Comparative analyses of the bearing capacity, failure mode, and load-paths between the equal-depth and unequal-depth beam models have been carried out.


Author(s):  
Shaosen Ma ◽  
Guangping Huang ◽  
Khaled Obaia ◽  
Soon Won Moon ◽  
Wei Victor Liu

The objective of this study is to investigate the hysteresis loss of ultra-large off-the-road (OTR) tire rubber compounds based on typical operating conditions at mine sites. Cyclic tensile tests were conducted on tread and sidewall compounds at six strain levels ranging from 10% to 100%, eight strain rates from 10% to 500% s−1 and 14 rubber temperatures from −30°C to 100°C. The test results showed that a large strain level (e.g. 100%) increased the hysteresis loss of tire rubber compounds considerably. Hysteresis loss of tire rubber compounds increased with a rise of strain rates, and the increasing rates became greater at large strain levels (e.g. 100%). Moreover, a rise of rubber temperatures caused a decrease in hysteresis loss; however, the decrease became less significant when the rubber temperatures were above 10°C. Compared with tread compounds, sidewall compounds showed greater hysteresis loss values and more rapid increases in hysteresis loss with the rising strain rate.


Author(s):  
J. Shi

Scatter in test results is common for relatively brittle materials such as ceramic matrix composites. The scatter may come from differences in material processing conditions, specimen machining/handling and from variations in test parameters for nominally the same test material. Large scatter in test results makes material modeling difficult. In the past, master curve concepts have been proposed to reduce scatter in tensile data and to interpret fatigue/creep results. In this paper, one such concept is examined in detail by applying it to the recent tensile test results of a SiC/SiC composite. It was found that the way to construct master curves did not apply to the CMC studied and thus a new master curve was developed to better represent the tensile data. In addition, the test data were analysed statistically based on the new master curve.


Author(s):  
Fayu Wang ◽  
Nicholas Kyriakides ◽  
Christis Chrysostomou ◽  
Eleftherios Eleftheriou ◽  
Renos Votsis ◽  
...  

AbstractFabric reinforced cementitious matrix (FRCM) composites, also known as textile reinforced mortars (TRM), an inorganic matrix constituting fibre fabrics and cement-based mortar, are becoming a widely used composite material in Europe for upgrading the seismic resistance of existing reinforced concrete (RC) frame buildings. One way of providing seismic resistance upgrading is through the application of the proposed FRCM system on existing masonry infill walls to increase their stiffness and integrity. To examine the effectiveness of this application, the bond characteristics achieved between (a) the matrix and the masonry substrate and (b) the fabric and the matrix need to be determined. A series of experiments including 23 material performance tests, 15 direct tensile tests of dry fabric and composites, and 30 shear bond tests between the matrix and brick masonry, were carried out to investigate the fabric-to-matrix and matrix-to-substrate bond behaviour. In addition, different arrangements of extruded polystyrene (XPS) plates were applied to the FRCM to test the shear bond capacity of this insulation system when used on a large-scale wall.


Author(s):  
Leila Ladani ◽  
Lalit Roy

Additive Layer Fabrication, in particular Electron Beam Additive Fabrication (EBAF), has recently drawn much attention for its special usability to fabricate intricately designed parts as a whole. It not only increases the production rate which reduces the production lead time but also reduces the cost by minimizing the amount of waste material to a great extent. Ti6Al4V is the most common type of material that is currently being fabricated using EBAF technique. This material has been used in aerospace industry for several reasons such as excellent mechanical properties, low density, great resistance to corrosion, and non-magnetism. The effects of build direction of layers (namely, addition of layers along one of the x, y & z directions with respect to the build table) and the anisotropy effect caused by it has not been explored vigorously. This anisotropy effect has been investigated in this work. Different mechanical properties such as Yield Strength (YS), Ultimate Tensile Strength (UTS), and Modulus of Elasticity (E) of these three types of Ti6Al4V are determined using tensile tests and are compared with literature. The tensile test results show that YS and UTS for flat-build samples have distinguishably higher values than those of the side-build and top-build samples.


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Hui Chen ◽  
Jinjin Zhang ◽  
Jin Yang ◽  
Feilong Ye

The tensile behaviors of corroded steel bars are important in the capacity evaluation of corroded reinforced concrete structures. The present paper studies the mechanical behavior of the corroded high strength reinforcing steel bars under static and dynamic loading. High strength reinforcing steel bars were corroded by using accelerated corrosion methods and the tensile tests were carried out under different strain rates. The results showed that the mechanical properties of corroded high strength steel bars were strain rate dependent, and the strain rate effect decreased with the increase of corrosion degree. The decreased nominal yield and ultimate strengths were mainly caused by the reduction of cross-sectional areas, and the decreased ultimate deformation and the shortened yield plateau resulted from the intensified stress concentration at the nonuniform reduction. Based on the test results, reduction factors were proposed to relate the tensile behaviors with the corrosion degree and strain rate for corroded bars. A modified Johnson-Cook strength model of corroded high strength steel bars under dynamic loading was proposed by taking into account the influence of corrosion degree. Comparison between the model and test results showed that proposed model properly describes the dynamic response of the corroded high strength rebars.


Author(s):  
Micah Hodgins ◽  
Alexander York ◽  
Stefan Seelecke

This work presents the design, fabrication and testing of a comprehensive DEAP test station. The tester is designed to perform tensile tests of planar DEAPs while measuring quantities such as tensile force, stretch, film thickness and voltage/current. The work details the specimen preparation and how the specimen is placed in the clamps. While the assembly process is performed by hand features were built-in to the design of the specimen frame and clamps to enable reliable placement and specimen geometry. Test results of the pure-shear specimen demonstrated good performance of the testing device. Although the electrode surface was rough the thickness stretch was evident during the stretching/actuation of the DEAP actuator.


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