SELF-ALIGNING/SPHERICAL SEATING

Spherical seatings are designed to be centered on the loading axis of an electromechanical or hydraulic universal testing 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.

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

Principle of Operation

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°) 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 are typically used in conjunction with a plane (fixed) compression platen.

Application Range

• Type of loading: Static compression

• Specimen material: Concrete, metals, wood, composites or other materials

• Specimen types: Cylinders, cubes, fasteners (when used in conjunction with other fixtures) or components

Safety Advice

Review safety note on page 234