按摩头形状对人体颈部组织力学作用的影响

目的通过建模仿真评价不同尺寸按摩头作用下的人体颈部组织响应,为按摩器设计提供指导。方法通过CT扫描获得按摩部位的人体组织灰度图像,使用逆向重建方法建立人体按摩部位组织的三维模型,使用非线性有限元方法分析在10 mm和15 mm两种半径按摩头在逐渐压入10 mm过程中肌肉和颈椎内承受应力、应变和按摩力的变化规律,以及对骨骼和组织的损伤和影响。结果 15 mm半径按摩头压入深度分别为6、7 mm时,局部最大应力分别为3.0、3.4 MPa,超过人体静脉损伤极限;压入深度6 mm时在颈椎骨产生1 MPa左右的应力。10 mm半径按摩头在压入深度分别为5、6 mm时,局部最大应力分别为3.2、3.7 MPa,超过人体静脉损伤极限;压入深度8 mm以上时在颈椎骨产生1 MPa以上的应力。结论从避免局部损伤来说,10 mm按摩头的按压深度不宜超过5 mm,15 mm半径按摩头不宜超过7 mm;大按摩头作用范围大,按摩力更柔和。

Influences of Massage Head Shape on Mechanical Responses of Human Neck Tissues

Objective To evaluate the mechanical responses of human neck tissues under the influence of massage head by modeling and simulation, so as to provide guidance for the design of massage apparatus. Methods Gray images of human tissues under application of message head were obtained through CT scanning, and the three-dimensional (3D) model for these tissues was established with reverse engineering method. Changes in strain, stress and message force of muscles and cervical vertebrae under the application of message head with the radius of 15 mm and 10 mm and pressed depth from 0 mm to 10 mm, as well as its damage and influence to bones and tissues were analyzed by finite element method. Results When 15 mm-radius massage head moved in depth of 6 mm and 7 mm, the maximum local stress was 3.0 MPa and 3.4 MPa, which was beyond damage limit of the vein. In contrast, when 10 mm-radius massage head moved in depth of 6 mm and 7 mm, the maximum local stress was 3.2 MPa and 3.7 MPa, which was beyond damage limit of the vein. To derive 1 MPa stress in cervical spine, the 15 mm- and 10-mm radius massage head should move in depth of 8 mm and 6 mm, respectively. Conclusions To avoid the local tissue damages, the pressed depth of massage should not be greater than 5 mm and 7 mm with the 10 mm- and 15 mm-radius message head, respectively. The message head with a larger radius could produce a larger action range and a more moderate massage force.