A material testing system that uses at least one hydraulic grip is improved with cable clips that are attachable to a respective lateral side of each hydraulic grip wedge. Each cable clip has another end that extends to engage a cable(s) extending from a corresponding wedge retention spring hole. The cable(s) enable manual extension of a wedge retention spring for engagement and disengagement from the hydraulic grip wedge. The cable clip maintains the cable in a noninterfering position during operational use of the material testing system.

A device for fixing a rock sample, including: a lower clamp and an upper clamp; the lower clamp including a lower connector connected to a loading base at a bottom of a testing machine, a lower end cap for fixing samples, a lower chain connecting the lower connector and the lower end cap, a first spiral spring, a first central position-limit mechanism, a second central position-limit mechanism, and a first hydraulic mechanism; the upper clamp including an upper connector connected to a loading base at a top of the testing machine, an upper end cap for fixing samples, an upper chain connecting the upper connector and the upper end cap, a second spiral spring, a third central position-limit mechanism, a fourth central position-limit mechanism, and a second hydraulic mechanism.

When mounting a grip 10 on a cross head 73, a pin 62 and an adapter 50 are removed from a joint 40. Then, a boss 13 of the grip 10 is inserted into a hollow part 45 of the joint 40, and the pin 62 is inserted into a through-hole 14 formed in the boss 13 of the grip 10 and a hole part 42 formed in a tubular body 41 of the joint 40. When mounting a platen 30 on the cross head 73, the adapter 50 is mounted on the joint 40. In addition, the platen 30 is mounted on the adapter 50. Further, a set screw is inserted into a hole part 52 of the adapter 50.

A device for fixing a rock sample, the device including: a lower clamp and an upper clamp. The lower clamp includes: a lower connector connected to a bottom loading base, a lower end cap for fixing samples, a lower chain connecting the lower connector and the lower end cap, a first spiral spring, a first central position-limit mechanism, and a second central position-limit mechanism. The lower end cap includes: a first sample fixing groove and a first connecting segment. The upper clamp includes: an upper connector connected to a top loading base, an upper end cap for fixing the samples, an upper chain connecting with the upper connector and the upper end cap, a second spiral spring, a third central position-limit mechanism, and a fourth central position-limit mechanism. The upper end cap includes a second sample fixing groove and a second connecting segment.

A modular test fixture is configured to quickly support test samples of different configurations for testing.

Provided is a clamp of elastic box of stiff true-triaxial testing system and a displacement monitoring method for cuboid specimens. The clamp includes six pressing plates and eight plate springs, which form an elastic pressure box. One surface of the elastic pressure box can be disassembled, which simplifies the steps of rock sample mounting, and saving the mounting time. The springs connected with the pressing plates ensures the stability of the clamp but cannot affect the stress state of other surfaces of the rock sample during the test of the rock sample, thereby ensuring test accuracy. The invention further provides a displacement monitoring method for the rock sample by using the elastic box clamp. Six displacement sensors are mounted on the elastic box clamp, and the displacement of the rock sample can be monitored in real time.

A modular test fixture is configured to quickly support test samples of different configurations for testing.

A tensile testing apparatus includes a specimen cartridge and a jaw actuator. The jaw actuator is operable to grip and pull a specimen in tension. The specimen cartridge is operable for holding multiple specimens. The specimen cartridge is rotatable for sequentially presenting specimens to the jaw actuator.

A tensile testing apparatus includes a specimen cartridge and a jaw actuator. The jaw actuator is operable to grip and pull a specimen in tension. The specimen cartridge is operable for holding multiple specimens. The specimen cartridge is rotatable for sequentially presenting specimens to the jaw actuator.