A test fixture for mechanically testing breast implants includes a frame, a base plate coupled with the frame, and a first actuator coupled with the base plate for providing reciprocating motion to the base plate along a first axis. The test fixture includes a compression plate coupled with the frame that opposes the base plate, a second actuator coupled with the compression plate for providing reciprocating motion to the compression plate along a second axis that intersects the first axis, and a third actuator coupled with the compression plate for providing reciprocating motion to the compression plate along a third axis that intersects both the first axis and the second axis. The test fixture includes a control system in communication with the first, second, and third actuators for controlling the movement of the base plate along the first axis and the movement of the compression plate along the second and third axes.

An example flexible substrate testing system includes: a first substrate support structure configured to hold stationary a first portion of a flexible substrate under test; a second substrate support structure configured to hold a second portion of the flexible substrate; an actuator configured to move the second substrate support structure to fold the flexible substrate and to unfold the flexible substrate; and a load cell configured to measure a load on the flexible substrate.