Abstract:

Objective The development of winter speed competitive sports apparel requires accurate measurement of the drag force on different parts of the apparel during the movement. In the traditional drag-reducing apparel testing session, a rigid mannequin is usually used to wear the apparel for wind tunnel air resistance testing. The combination of a flexible mannequin that simulates the mechanical properties of human skin and thin-film piezoelectric sensors can be used to obtain the drag reduction effect of the garment on the overall and localized critical parts of the athlete during the sports posture.

Method Based on the three-dimensional human body data of athletes' dynamic posture in winter sports, the mannequin model was constructed by using reverse engineering software, the structure of rigid inner shell and flexible skin layer of the platform was set up, and the model of the platform was divided into five parts for the convenience of putting on and taking off of the garment, and the placement points of thin-film piezoelectric sensors were designed by combining with the methods of aerodynamic dynamics, so as to build up the complete sensing system for the platform, and develop an intelligent and flexible mannequin for winter sports.

Results Comparative tests were carried out on the flexible mannequin in a wind tunnel with three different angles. The overall pressures measured for the rigid mannequin and the flexible mannequin under the same wind speeds indicated differences in the test results between the two mannequins. The flexible mannequin exhibited significantly lower pressure values at each point when the mannequins were clad, highlighting its noticeable drag reduction effect on the human body when wearing speed skating apparel. When three different sets of speed skating apparel were tested under the same wind speed conditions, the pressure values at the same location were close between speed skating apparels 1 and 2, despite their different sizes. This suggested that the mannequin was able distinguish between different degrees of deformation in the flexible skin layer. Additionally, when comparing speed skating apparels 1 and 3, which have different styles but the same size, significant differences in pressure values at different locations on the mannequin were visually observable. This demonstrates that the flexible mannequin can differentiate inconsistent structural designs in different parts of the apparel, facilitating comparative analysis and optimization of detailed drag reduction designs.

Conclusion Based on the flexible sensing technology, an intelligent flexible mannequin for winter speed skating sportswear drag reduction performance testing has been developed, which consists of a rigid inner shell and a flexible epidermal layer, and integrates multiple flexible pressure sensors to directly obtain the wind resistance pressure data endured by each part of the flexible mannequin. The test results show that the mannequin can realize real-time synchronous acquisition of multi-point pressure signals, which not only get the specific resistance data of local key parts of the human body, but also simulate and test the resistance reduction effect of speed skaters wearing different materials or different structural design of the competition garments under the sports conditions. The pressure signals can also be used to evaluate the resistance reduction of different parts of the competition garments. The intelligent mannequin plays the application value of flexible sensors in the design of clothing resistance reduction structure, makes the clothing resistance reduction test simpler and more accurate, and is more suitable for the pressure test field of winter sports competition clothing.

Key words: flexible mannequin, flexible sensor, clothing drag reduction, speed skating suit, winter spor