可变刚度缓冲鞋垫结构设计及优化

Structural Design and Optimization of Cushioning Insole with Variable Stiffness

目的设计X型结构变刚度缓冲鞋垫,探究其对糖尿病截趾患者足底表面压力和内部应力的影响。方法基于CT影像建立糖尿病截趾患者足部-小腿有限元模型,根据足底压力分布特征进行鞋垫区域划分。设计X型结构3D打印缓冲鞋垫,通过改变结构面板厚度改变结构的模量,对划分区域填充不同模量的X型结构方案进行仿真分析。结果糖尿病截趾患者足底峰值压力在跟骨区,足趾区选用面板厚度1.2 mm结构、跖骨区选用面板厚度1.4 mm、足弓区选用面板厚度2.0 mm和足跟区选用面板厚度1.6 mm组合后的鞋垫减压效果最好。与赤足相比,此方案鞋垫分别降低足跟区峰值压力、趾骨区峰值压力和足底软组织内部应力40.18%、31.7%和50.45%。结论变刚度下3D打印鞋垫可有效降低足底表面压力、内部应力,减小二次截趾概率。

Objective An X-shaped cushioning insole with variable stiffness was designed to explore its effects on plantar pressure and internal stress of diabetic patients with toe amputation.Methods Based on CT images,the foot-lower extremity finite element model of diabetic patients with toe amputation was established,and the insole was divided into different areas according to distribution characteristics of the planter pressure.The three-dimensional(3D)printed cushioning insole with an X-shaped sandwich structure was designed.The modulus of the sandwich structure was changed by changing thickness of the sandwich structure panel.For simulation analysis,the divided area was filled with the X-shaped sandwich structure with different modulus.Results The peak plantar pressure of diabetic patients with toe amputation was in calcaneal region,and the combined insoles with 1.2 mm panel thickness in toe area,1.4 mm panel thickness in metatarsal area,2.0 mm panel thickness in middle foot area and 1.6 mm panel thickness in heel area had the best decompression effect.Compared with bare feet,the peak pressure in heel area of the insole,the peak pressure in phalangeal head area and the stress in plantar soft tissues were reduced by 40.18%,31.7%and 50.44%,respectively.Conclusions The 3D printed insoles with variable stiffness can effectively reduce surface pressure and internal stress of the sole and reduce probability of the 2^(nd) toe amputation.