Bioengineering Program, Georgia Institute of Technology, Atlanta, GA, USA.
School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
Prosthet Orthot Int. 2021 Jun 1;45(3):240-245. doi: 10.1097/PXR.0000000000000018.
A mechanical testing protocol was used to compare the material properties of commercially available foams with that of a newly designed granular jamming orthosis prototypes.
Foot orthoses have an inherent limitation of predetermined mechanical material properties coupled with a fixed orthotic interface shape that cannot be readily changed.
To develop and test a novel orthotic insole design concept that incorporates principles of granular jamming.
Granular media were used in combination with vacuum pressure to create a variable stiffness granular foot orthosis. Four types of granular media (rice, poppy seeds, micropolystyrene, and polystyrene beads) were tested in different prototype configurations varying in volume fill and particulate size. Stress-strain curves were obtained from uniaxial compression tests to characterize granular foot orthosis prototypes in comparison with commercial orthotic foams.
Increasing vacuum pressure increased prototype stiffness for most configurations. A single granular jamming orthosis could exhibit energy absorption values that spanned the entire commercial foam performance range, and in some cases extended far beyond the upper values of the tested foams.
The results suggest that granular jamming principles can provide clinicians the capability for rapid selection of mechanical properties over a wide range of orthosis stiffnesses. Importantly, patients could don the orthosis because the clinician makes real-time assessments and adjustments in the clinic.
采用机械测试方案，比较市售泡沫材料与新型颗粒摩擦固定矫形器原型的材料特性。
足部矫形器存在固有局限性，其机械材料特性预先确定，且矫形器的固定界面形状无法轻易改变。
开发并测试一种新型矫形鞋垫设计理念，该理念结合了颗粒摩擦固定原理。
使用颗粒材料并结合真空压力，制造出具有可变硬度的颗粒摩擦足部矫形器。对 4 种不同类型的颗粒材料（大米、罂粟籽、微聚苯乙烯和聚苯乙烯珠）进行了测试，研究了不同的原型配置，包括体积填充和颗粒尺寸。通过单轴压缩试验获得应力-应变曲线，对颗粒摩擦足部矫形器原型与商业矫形泡沫进行了比较。
增加真空压力会增加大多数配置的原型硬度。单个颗粒摩擦固定矫形器可以表现出跨越整个商业泡沫性能范围的能量吸收值，在某些情况下，甚至超出了测试泡沫的上限值。
结果表明，颗粒摩擦固定原理可以为临床医生提供在广泛的矫形器硬度范围内快速选择机械性能的能力。重要的是，患者可以穿上矫形器，因为临床医生可以在诊所进行实时评估和调整。
