*By: Dr. Francesc Puigvert Cobos, Grasse Zur Ingenieurgesellschaft mbH, Berlin / Germany
Strength, lightness, stiffness and durability are some of the reasons why Fibre Reinforced Polymers (FRPs) are increasingly being employed in many engineering sectors. As the research for new material configurations, the development of automated manufacturing techniques and the range of applications continue to rise, innovative and improved testing methodologies need to continuously be developed in order to optimise their analysis and design. Therefore, reliable testing methodologies which are able to take into account the complex material behaviour of composites are required.
Together with the tensile and compressive mechanical properties of composite materials, the in-plane shear properties also play an important role. In this case, the loading direction is not along the fibres and, therefore, the anisotropy of these materials is highlighted. The strength of the material decreases when the loading direction is shifted and, consequently, not only depends on the reinforcing fibres, but also on the interaction between the fibre/matrix. Regarding the determination of in-plane shear properties, several test methods are widely used. These generally include the Short Beam Shear (ASTM D 2344), the Iosipescu Shear (ASTM D 5379), the ±45° Tensile Shear (DIN EN 14129), the Torsional Tube Shear (ASTM D 5448), the Two- and Three-Rail Shear (ASTM D 4255), the V-Notched Rail Shear (ASTM D 7078).
The extensive variety of testing methods is due to the difficulty in determining the in-plane shear properties of composite materials by means of a pure and uniform shear distribution throughout the test specimen up to failure. Therefore, each methodology presents its own advantages and disadvantages.
Automotive manufactures are employing a wide range of new materials to reduce the weight of their vehicles and reduce emissions. These materials include new, high-strength steel and aluminum alloys, and a huge range of plastics and composites. Of these materials, continuous carbon fiber polymer composites offer the greatest potential for lightweight structures; however, there are many barriers to their widespread introduction.
Currently the cost and process times of composites parts is significantly higher than traditional metals. This is being addressed by the development of new matrix materials and manufacturing processes. Recycling of composite materials is being addressed and progress is being made with new thermoplastic matrix composite materials, which are easier to recycle than thermoset matrix materials. Finally, the unique nature of composite materials presents designers and engineers with new challenges and the successful use of composite materials requires a thorough understanding of their mechanical properties.
Explore how DIC is best suited for testing composites in the automotive industry and testing medical devices for new product development.
European Conference on Composite Materials (ECCM17)Be sure to stop by our booth to speak with Andrea Calzolari, Peter Bailey, and Ian McEnteggart about your composite application questions! ECCM17 is taking place June 26-30th in Munich, Germany.
|5969 Testing System||ElectroPuls™ E1000||CEAST 9340 Drop Tower|
JEC Paris 2016
We had the pleasure of exhibiting at JEC Paris 2016, allowing us the chance to speak with customers from more than 30 countries!
This year, we demonstrated machines from our Electromechanical (Static), Dynamic, and CEAST product lines. Additionally, we spoke to attendees about Digital Image Correlation (DIC) Software that can be used with the Advanced Video Extensometer.
Downloadable White Papers
- Composites Gripping Guide
- Characterizing Complex Materials with Impact Testing
- A Review of Contacting Strain Measurement Techniques for Composites Laminate Testing
- The Effect of Frame Alignment on Tensile Test Data
- A Review of Current In-Plane Composites Compression Testing Methods & Standards
About Strain Measurement
Do You Struggle with Managing Too Many Test Standards?
As Featured In
- AM&P Magazine: Using Digital Image Correlation to Measure Full Field Strain
- Aerospace Manufacturing: Taking the Strain
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