Determination of In-plane Shear Strength of Unidirectional Composite Materials Using the Off-axis Three-point Flexure and Off-axis Tensile Tests

2010 ◽  
Vol 44 (21) ◽  
pp. 2487-2507 ◽  
Author(s):  
G. Vargas ◽  
F. Mujika
Keyword(s):  
Shear Strength ◽  
Composite Materials ◽  
Tensile Tests ◽  
Unidirectional Composite ◽  
Point Of View ◽  
Experimental Point ◽  
Plane Shear ◽  
Lift Off ◽  
Flexure Test

The aim of this work is to compare from an experimental point of view the determination of in-plane shear strength of unidirectional composite materials by means of two off-axis tests: three-point flexure and tensile. In the case of the off-axis three-point flexure test, the condition of small displacements and the condition of lift-off between the specimen and the fixture supports have been taken into account. Some considerations regarding stress and displacement fields are presented. The in-plane shear characterization has been performed on a carbon fiber reinforced unidirectional laminate with several fiber orientation angles: 10°, 20°, 30°, and 45°. Test conditions for both off-axis experimental methods, in order to ensure their applicability, are presented. Off-axis flexure test is considered more suitable than off-axis tensile test for the determination of in-plane shear strength.

In-Plane Shear Strength Determination of Composite Materials in Laminated and Sandwich Panels

1997 ◽  
Vol 50 (11S) ◽  
pp. S237-S240 ◽  
Author(s):  
J. R. Vinson
Keyword(s):  
Shear Strength ◽  
Composite Materials ◽  
Test Procedure ◽  
Sandwich Panels ◽  
Laminated Composite ◽  
Adhesive Bond ◽  
Shear Stresses ◽  
Plane Shear ◽  
Laminated Composite Materials

A simple test procedure is available to determine the in-plane shear strength of laminated composite materials, as well as other orthotropic and isotropic advanced material systems. The test apparatus is simple, inexpensive, and the flat rectangular plate test specimen is not restricted in size or aspect ratio. In addition to its use for laminated composite materials, the test can also be used for foam core sandwich panels. In sandwich panels, the tests can be used to determine the in-plane shear strength of the faces, the core and/or the adhesive bond between face and core. The shear stresses developed vary linearly in the thickness direction and are constant over the entire planform area.

scholarly journals Influence of graphite morphology on static and cyclic strength of ferritic nodular cast iron

2018 ◽  
Vol 165 ◽  
pp. 14014 ◽  
Author(s):  
Christian Gebhardt ◽  
Geng Chen ◽  
Alexander Bezold ◽  
Christoph Broeckmann
Keyword(s):  
Cast Iron ◽  
Nodular Cast Iron ◽  
Tensile Tests ◽  
Cyclic Strength ◽  
Fatigue Tests ◽  
Point Of View ◽  
Experimental Point ◽  
Suitable Material ◽  
Material Parameters ◽  
Perfectly Plastic

High silicon alloyed nodular cast iron consists of a purely ferritic matrix and graphite nodules, mainly. Varying wall thicknesses and manufacturing conditions result in different graphite morphologies throughout a structural component. From an experimental point of view, axial fatigue and tensile tests were carried out on specimens with differently degraded graphite. From a numerical point of view, the microstructure has been modelled using a finite element (FE) approach with representative volume elements (RVE). The RVE models were built according to micrographs of fatigue specimens. The generated RVEs determine effective material properties through elasto-plastic homogenization and were subsequently analysed using a shakedown approach. In shakedown theory, the material re-enters the elastic regime after a few cycles of initial plastic deformation. This work uses the shakedown theorem to derive a lower bound estimation of the endurance limit from a non-incremental simulation. Here, the material has to be modelled elastic-perfectly plastic. The major challenge in modelling nodular cast iron is to determine suitable material parameters for the graphite and ferrite phase, revealed by parameter studies on the static and cyclic model. By using reasonable material parameters, fundamental effects, observed in the fatigue tests, were reproduced on the model level.

Analysis and Testing of Dynamic Micromechanical Behavior of Composite Materials at Elevated Temperatures

1996 ◽  
Vol 118 (4) ◽  
pp. 554-560 ◽  
Author(s):  
R. H. Pant ◽  
R. F. Gibson
Keyword(s):  
High Temperature ◽  
Composite Materials ◽  
Elevated Temperatures ◽  
Flexural Modulus ◽  
Flexural Vibration ◽  
Unidirectional Composite ◽  
Vibration Test ◽  
Impulse Frequency ◽  
Composite Moduli

This paper describes the use of a recently developed high temperature impulse-frequency response apparatus to directly measure dynamic modulus and internal damping of high temperature composite materials, matrix materials, and reinforcing fibers as a function of temperature. An extensional vibration test was used for determination of the complex Young’s modulus of fiber specimens as a function of temperature. A flexural vibration test was used for determination of the complex flexural modulus of matrix and unidirectional composite specimens (0 and 90 deg fiber orientations) as a function of temperature. These results were obtained from tests done on two different fiber reinforced composite materials: boron/epoxy (B/E) and Silicon Carbide/Ti-6Al-4V (SiC/Ti). The results from these tests were then used to assess the validity of micromechanics predictions of composite properties at elevated temperatures. Micromechanics predictions of composite moduli and damping at elevated temperatures show good agreement with measured values for the 0 deg case (longitudinal) but only fair agreement for the 90 deg case (transverse). In both cases, the predictions indicate the correct trends in the properties.

Sign in / Sign up

Export Citation Format

Share Document