Glenn's revolutionary Shape Memory Alloy Rock Splitters (SMARS) device is fabricated from nickel-titanium-halfnium (NiTiHf), nickel-titanium-zirconium compositions, or a combination. These compositions contain a secondary, nanometer-sized precipitate phase that is produced through processes of compositional control and aging heat treatments. Glenn's novel materials and processes have yielded a shape memory alloy (SMA) composition that produces much higher stresses than other SMAs on the commercial market.
The SMARS device is composed of:
- SMA material as the actuating member
- a casing heater placed around the SMA member
- a DC or AC power source to provide current through the heater
- pointed tips for acute penetration into rock formations
- a hand press to reset the SMA element after each use.
In the rock-splitting process, a hole equal to the diameter of the SMA element is drilled in the portion of the rock where the fracture is desired. Next, the pre-compressed SMA is inserted into the hole, and AC or DC current is applied to energize the device's heaters. Once the heater achieves the critical transformation temperature, the SMA will begin to expand within seconds. Since its expansion is constrained by the rock walls, the SMA will eventually exert up to 1,500 MPa of stress, splitting the rock apart. When the current is removed and the heater cools, the SMA material returns to its pre-compressed state. At this point, the material can be recovered, so the process is repeatable after reshaping.
The SMA actuating members were also designed to achieve displacement greater than the material's strain output. Glenn's SMARS device provides high-powered rock fracturing that is controllable, reliable, and comparatively simple without the use of explosives, hydraulics, or chemicals.