Home arrow Tech Briefs arrow Mechanics & Machinery arrow Biaxial and Shear Testing Apparatus With Force Controls
Biaxial and Shear Testing Apparatus With Force Controls Print E-mail
Naval Undersea Warfare Center   
Jul 31 2008

This apparatus is intended especially for measuring strength properties of fabrics.

Advertisement:

An apparatus for in-plane biaxial tension/compression and in-plane shear testing of fabrics, other flexible sheet materials, or relatively rigid thin plate materials has been invented. The apparatus is capable of applying, to a sheet material specimen, a controlled tensile or compressive force along each of two directions in the plane of the specimen. The force along each direction can differ from the force along the other direction. The directions of the applied forces can be orthogonal or can be set at an oblique angle, depending on the combination of stresses required to be applied to the specimen. Thus, depending on the angle between the applied-force directions, the sense (tensile or compressive) of each applied force, and the magnitude of each force, the specimen can be subjected to almost any combination of in-plane shear and biaxial tension/compression loading.

Image
This Apparatus Applies Controlled Forces to a sheet or thin plate specimen along two in-plane directions. The forces can be equal or unequal. The directions can be mutually orthogonal or oblique.
The apparatus (see figure) includes two rhombus four-bar linkages in vertical planes that intersect at a top joint and a bottom joint on a common vertical axis. The top and bottom joints include thrust bearings that enable rotation, about the common vertical axis, of the plane of one linkage relative to the plane of the other linkage so as to obtain the desired angle between the directions of the applied forces. The top and bottom joints are connected to the top crosshead and the bottom crosshead, respectively, of a conventional controlled- displacement tension/ compression testing machine. Located at the lateral joints of each four-bar linkage there are loading-plate assemblies that include loading plates connected to piston actuators. The specimen is clamped to the loading plates of either or both four-bar linkage(s), depending on the nature of the required test load. The conventional tension/ compression testing machine serves mainly as an adjustment mechanism: By raising or lowering the top joint, the horizontal distance between the lateral joints in each four-bar linkage is set to the value required to obtain the proper fit to the specimen to be clamped to the loading plates.



 

Dedicated to helping you design better products in a digital world... your guide to the latest tools & techniques for digital prototyping, simulation, and analysis of the real-world performance of your ideas.

Visit the Digital Design Center

>> Most Searched

>> New Download



Microwave & RF Technology Download the FREE PDF issue here

>> Newsletter

Subscribe today to receive the INSIDER, a FREE e-mail newsletter from NASA Tech Briefs featuring exclusive previews of upcoming articles, late breaking NASA and industry news, hot products and design ideas, links to online resources, and much more.

Your name:

Your email:

Please Subscribe me to the Insider

>> Syndicate