Dynamic Countermeasure Fabrics for Post-Spaceflight Orthostatic Intolerance.

Area of Science:

• Biomedical Engineering
• Materials Science
• Aerospace Medicine

Background:

• Traditional aerospace orthostatic intolerance garments (OIG) are often pneumatic, limiting mobility and requiring external air supplies.
• Existing elastic compression garments present usability challenges, including difficulty in donning/doffing and discomfort due to constant compression.

Purpose of the Study:

• To evaluate novel contractile shape memory alloy (SMA) knitted actuators for developing low-profile, dynamic compression OIG.
• To assess the functional capabilities and compression potential of SMA knitted actuators for aerospace applications.

Main Methods:

• Displacement control testing of 10 SMA actuator samples with varying geometric parameters.
• Thermal cycling under different structural strains (0-45%) to measure inactive and actuated forces.
• Approximation of compression capabilities using medical hosiery standards and aerospace population anthropometric data (ANSUR 2012).

Main Results:

• Predicted dynamic compression reached 52 mmHg (single layer) and 105 mmHg (double layer) at the ankle.
• Low inactive pressures (<20 mmHg) confirmed controllable compression.
• Actuation increased pressure up to 33 mmHg (single layer) and 67 mmHg (double layer).

Conclusions:

• SMA knitted actuators show potential for low-profile, dynamic compression garments to manage orthostatic intolerance in aerospace.
• This technology offers therapeutic pressures suitable for astronauts and has potential for terrestrial medical and high-performance aircraft use.