A versatile method is proposed to predict the shape of a paper model of a three piece brassiere cup. A brassiere cup consists of several cloth and wire parts and the shapes of cloth parts called patterns are determined by repeating creation of a paper cup model, check of its 3D shape, and modification of 2D shapes of patterns. For efficient design of a brassiere cup, prediction of its 3D shape with a simulation is required. The deformed shape of a paper pattern is represented as a single or multiple developable surfaces. So, a model that can represent a pattern both as a single surface and as multiple surfaces is proposed. Which case is selected depends on the magnitude of the potential energy of the pattern in each case. The potential energy of the pattern and geometric constraints imposed on the pattern are formulated based on the model. Minimizing the potential energy under geometric constraints derives the stable shape of the pattern in either case. The validity of the proposed method was verified by comparing predicted and measured 3D shapes of paper models of two types of three piece cups.

Surging in the false-twisting machine degrades yarn quality. Surging is a yarn vibration phenomenon, and its cause has not been clarified. It is an important issue to clarify the causes of surging from the viewpoint of the textile industry. Investigating the causes of surging contributes to not only higher processing speed but also higher processing efficiency. This investigation also contributes to stabilizing the yarn quality at the false-twisting production site. In this study, a disc-friction type model machine was used to evaluate the yarn conditions of false twisting with and without surging. It was observed that surging tends to occur at low drawing ratios and high-speed processing. In the addon twisting area, the number of twists, drawing quantity, yarn tension, yarn temperature, and heating time decreased because of the occurrence of surging. These results show the actual condition of the yarns with surging and confirm the interrelationship between surging and processing conditions of false twisting.