Application of carbon fiber materials in prosthetic

Prosthetics is the earliest and fastest developing field in rehabilitation engineering, among which prosthetics of lower limbs developed the earliest and fastest. Due to the complexity of human movement organs, the structure of lower limb prostheses that conform to the trajectory of the human body is also more complicated, and its mass will increase accordingly, and the mass of the prosthesis has a direct impact on the energy consumed by lower limb amputation patients.

Therefore, in order to effectively reduce the quality of prostheses, some high-strength and light-weight materials, such as ultra-light aluminum alloys, titanium alloys, and carbon fiber composite materials, are widely used in the production of prosthetic parts, making modern prostheses more complete and better in quality. Lightweight, especially carbon fiber composite materials, in addition to the above advantages, it also performs well in terms of damage safety.

1. Prosthetic foot

The main function of the prosthetic foot is to support the mass of the body, generate thrust during exercise, and at the same time compensate for the effects of the calf triceps and flexors. The prosthetic foot that compensates for these functions undergoes a revolutionary change in the 1980s, that is, there is Energy storage foot. The earliest energy-storage prosthesis was the Seattle foot, which was published in 1981. It is considered a breakthrough point in the field of prosthetics for designing prosthetic feet based on new principles.

From a dynamic point of view, the foot stores energy in the early stage of support and releases energy in the later stage. Due to the special design and material of the energy storage foot, the energy discharge/storage ratio is generally above 50%, which is higher than that of the traditional prosthetic foot. Among the energy-storing feet, the prosthetic feet made of high-elasticity and high-strength carbon fiber composite materials are the highest, which can reach more than 95%. At the same time, because of their light weight, patients can save effort when walking and are popular.

2. Ankle

The movement of the ankle joint and the prosthetic foot has an important influence on the support and stability of the knee joint. Carbon fiber composite materials can also be used for the production of the ankle joint. For example, Germany's Ottobock company uses carbon fiber composite material for the ankle joint in the flexible foot, which can bounce. Taiwan Delin company has carbon fiber fixed soft heel ankle, carbon fiber universal ankle and other artificial ankle joints. In addition, the joint tube of the ankle and calf prosthesis can also be made of carbon fiber composite material, so that the ankle joint is light and beautiful.

3. Knee

In addition to the foot plate, a very important prosthetic component is the knee joint, which has also been made of carbon fiber composite materials. According to different materials, knee joints are divided into ordinary joints, aluminum alloy joints, titanium alloy joints, magnesium alloy joints, and carbon fiber joints. Among them, ordinary joints have large mass; aluminum alloy joints are light, but their strength and service life are limited; titanium alloy joints are light, strong, but expensive; and carbon fiber joints are relatively expensive, but their specific strength is the above The best of the materials. Therefore, the outer frames of more than 20 knee joints that are currently popular in the world are all made of carbon fiber composite materials.

4. Receptive cavity

In addition to the above-mentioned main components, another major component of the prosthesis is the receiving cavity. The so-called receiving cavity refers to the component used to accommodate the residual limb, transmit the force between the residual limb and the prosthetic limb, and connect the residual limb and the prosthetic limb. It is an important factor in determining the performance of the prosthesis. The basic requirement for the receptacle is that it is necessary to bear the body mass, control the prosthesis, and suspend the prosthesis during the operation.

The receiving cavity can be divided into hard receiving cavity and soft receiving cavity according to the materials used in manufacturing. Among them, the ISNY thigh soft receptacle successfully developed in Sweden is widely used. It uses a structure that separates the residual limb part and the mass part of the support. The former is made of a soft polyethylene board to make a transparent receiving cavity, and the latter is made of a composite support frame made of carbon fiber or carbon fiber-glass fiber mixed reinforced resin. The soft receiving cavity can adapt to the needs of muscle deformation and increase the contact surface between the receiving cavity and the skin, and the carbon fiber frame also meets the requirements of the quality of the support body and the transmission force.

The application prospect of carbon fiber in the field of prosthetics is very broad. At present, there are 8.77 million physical disabilities in China, of which more than 1 million need to be fitted with prostheses, and there are new increases every year. Many traditional prostheses have problems such as high quality, poor performance, and low standardization. The emergence of carbon fiber composite materials has greatly made up for the shortcomings brought by traditional materials.

SHIJIAZHUANG AOSUO O&P