what is the purpose of using the spherically seated compress

what is the purpose of using the spherically seated compression plate? (compression test steel)

Solution

Designed to be centered on the loading axis of an eletromechanical or hydraulic universal test machine. Compression platens provide a hardened surface for complex compression tests in which uniform stress distribution is critical. Spherical seating is accomplished differently depending on the model purchased. For some models, the spherical seat is integral to the compression platen, for others the spherical seat is purchased separately to convert a compression platen to a spherically seated platen. Both types are available in a range of diameters.

Designed to mount directly to the crosshead or table of the frame, these compression platens are available with numerous types of adapters, making them compatible with a wide range of testing platforms.

With a variety of diameters, compression platens fill a wide range of testing needs. They can be used to test a variety of materials, including concrete, metals, composites, and wood. The high Rockwell Scale hardness of the compression platens ensures lack of deformity at pressures up to their capacity. Their inscribed concentric circles ensure proper, centered placement of the specimen, thereby increasing the validity of test results. A level seating surface and even load distribution over the specimen is ensured due to the high tolerance in the flatness of the surface. This aids the operator in attaining valid test results and true failure measurements.

The spherically seated compression platens/seats are designed to accommodate angular displacement (up to 4 degrees) of the top of the specimen with reference to the machine’s loading axis. This is accomplished through the self-aligning action of the seat.

Spherically seated compression platens/seats are typically mounted to the crosshead of electromechanical or hydraulic UTM’s. They are normally used in conjunction with a plane compression platen that is mounted to the table of the machine.

The advantage of this type of compression plate set, which is comprised of a spherically seated upper compression plate and a fixed lower compression plate, is the ability of the upper spherically seated plate to self-align when contacting the specimen surface. This enables the application of a uniform load to non-parallel specimens such as finished products.