Abstract:

Objective It may be uncomfortable for human being to wear clothing that conforms to the static state during certain motion states. Since the hip of human body are complex curved bodies, pantsuits should not only fit the lower limbs under static state, but also meet the needs of dynamic deformation caused by motion. Therefore, it is necessary to explore the hip circumference requirements of trouser suit in different motion states so as to achieve the goal of fitting without binding.

Method The constraint relationship between human body characteristics and dynamic parameters of lower limbs was comprehensively analyzed, and the morphological variation rule of hip circumference section was discussed based on single leg and double leg lifting. The mathematical model between hip circumference and human characteristics, dynamic parameters of lower limbs was constructed, and the trend analysis and model modification were carried out.

Results In exploring the relationship between hip circumference and state parameters, the analysis was performed using the control variable method. The hip circumference size increased with the increase of lifting angle β in both unilateral and bilateral leg lifts, and the change rate increased continuously, and the slope of their curve increased sharply and changed more obviously after 80°, in which the hip circumference in the bilateral leg lift state was more sensitive to the lifting angle. The variation curve of Pants hip circumference with direction angle α was shown, in which β=45°. When the lifting angle of the single leg is 45°, the hip circumference of trouser suit will first decrease and then increase with the increase of the direction angle α. When the legs were raised 45°, the hip circumference of trouser suit gradually decreased with the increase of α, and rapidly decreased after 60°. In the application of the model, based on the basic leg range of motion of human body, 60°was used as the cut-off point and divided into two cases for discussion. When β≤60°, the walking state hip circumference was calculated and the results are shown in, where data show that the Pants hip circumference is closely related to human characteristics and the lower limb motion state parameters. In addition, the same subjects did different stride tests (samples 2 and 6) and it is clear that the increase in stride length increased their lifting angle by nearly 9°, which increased the value of Pants hip circumference by nearly 3 cm. For the situation where β > 60°, the sitting hip circumference and hip circumference increase were calculated and the results are shown. Among them, samples 2 and 4 were the same person at different fat and thin times, and it was found that the different sitting width parameters at their sitting posture led to larger differences in the increase of hip circumference. Even for the same person, the human body data at different time will alter, and it is necessary to measure in real time when making clothing customization.

Conclusion The relationship between hip circumference and the changes of human cross section is studied. Through the construction of mathematical model of hip circumference, the relationship between hip circumference, human characteristics and lower extremity state parameters is discussed, and a hip circumference model considering dynamic parameters of the lower extremity is established. When the leg lifting angle β≤60°, hip circumference line is parallel to waist circumference, pants do not bind the human body, hip circumference line does not produce fold accumulation phenomenon, and pants appear more elegant. All these can be calculated according to the angle range of individual movement needs hip circumference value. When β>60°, the hip circumference is inclined with the body. The pants do not bind the human body but will produce wrinkles which accumulates near the hip circumference. The seated width parameter is adopted to replace the hip circumference width. The maximum hip circumference after the change is selected as the minimum hip circumference of trouser suit without binding the human body under multiple lower limb movements. The model solves the influence of lower extremity motion state on hip circumference of pants, and can provide theoretical basis and reference for pants hip circumference plate making and clothing customization.

Key words: pants hip circumference, body feature, orientation angle, lifting angle, hip circumference model