||Ultrasonic is a transport form of sound. There is no mass transportation, only energy transportation occurs in transfer process. Recently, the ultrasonic was widely used in a variety of purposes. For example：sonar, non-destructive testing, washing and emulsification. Due to the effects of mechanical vibration of ultrasonic on the physiological can promote the percutaneous absorption, ultrasonic is widely used in medical cosmetic field. It can get amazing amount of spending and will continue growth every year. The skin is the body's largest organ, which can be divided into epidermis, dermis and hypodermis. There are two main approaches for drugs to be delivered through the skin: directly penetrate the epidermis and penetrate the lipid layer of cell space.|
The main purpose of this study is to executing numerical simulation through finite element analysis. By constructing the 3D FEM model of the skin, the effects of different level combinations of the three factors, massage time, amplitudes and frequencies of ultrasonic, on the equivalent strain distributions of the epidermis, dermis, hypodermis and muscle layers were studied, while the skin was massaged by using ultrasonic. The simulation results showed that the difference of maximum equivalent strain is nearly one hundred times between different factor’s level combinations. That means the choice of the appropriate factor’s level combination will affect the efficacy of ultrasonic massage seriously. The numerical simulation results also showed that amplitude is the most influential factor on the equivalent strain for every layers of skin except the epidermis.