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DEVICE TO PREVENT BUCKLING IN BIAXIAL TESTS OF CRUCIFORM SPECIMENS
WO20016467
The invention relates to a device for carrying out biaxial tests on a cruciform specimen (3), wherein the cruciform specimen (3) comprises arms and a central zone, such that the device comprises a first plate (1) and a second plate (2), configured to be joined to one another, and four plates (9) configured to compress the arms of the cruciform specimen (3), said device also optionally comprising an L-shaped support (10) configured for the plates (1, 2) to be connected to said support (10) with the cruciform specimen (3) therebetween. According to the invention, the plates (1, 2) are cross-shaped and comprise a specimen supporting face (4), such that said specimen supporting faces (4) comprise a plurality of fillets with blunt edges (5) or a knurled surface with beveled peaks (6).
An anti-buckling fixture is proposed for developing biaxial testing on cruciform specimens with at least one compressed direction. Its main differential characteristics are: - The arms of the cruciform specimen are not destabilized due to buckling. - Misalignments between the applied load direction and the arms axes are avoided to prevent the appearance of unexpected effects. - There is direct access and visualization of the biaxially loaded region to acquire the strain state by means of different techniques, for example Digital Image Correlation (DIC), videoextensometry, strain gages or fibre optic. - It allows studying either tension-compression or compression-compression loading cases. - It is adaptable and adjustable to any testing machine. - It is scalable to the geometry and dimensions of any type of cruciform specimen. - It is based in a modular concept that facilitates the assembly and disassembly as well as its possibilities of industrialization.