Effect Evaluation of Repeated Compression for Tactile Hardening of Cotton Pile Towel by Indentation Test

Abstract

Pile has a textured structure that contains voids and cavities, and the texture hardens with repeated use. It is advantageous to numerically evaluate the hardening characteristics of the pile texture for the development of the products such as towels. Then, the objective of this study is to establish an objective method for evaluating the hardening of the pile due to repeated use. In particular, to determine product specifications, it is necessary to define the conditions under which measurement results are stable. Therefore, for proper design of pile products, objective test methods for repeat use of the pile must be identified. This article reports the effect of repeated indentation testing with a spherical probe on towel samples folded in two to form four layers. A contact theory based on Hertzian theorem is used to evaluate the stiffening of the towel due to repeated indentation. For the properties evaluated in this extended contact theorem, the stiffening behavior is discussed by comparing the changes in the results of 20 repeated tests. In this discussion, the critical times of the indentation test are analyzed to quantify the characteristics of the stiffening behavior of the cotton towels. Analyzing the indentation times shows that critical conditions for the number of tests can be defined.