Effective research on the aesthetic characteristies of fabries is difficult because explicit definitions are lacking in this field. The most reliable tool is subjective evaluation: therefore, words ( loft, clammy, hard, etc.) become important research tools.Special meanings of these words become clear if they are logically arranged according to textile frames of reference.Fabric aesthetic character is defined as a relationship among a minimum of six concepts: STYIE, BODY, COVER, SURFACE TEXIURF, DRAPE, and RESILIENCEE. These concepts can be described by how they are subjectively perceived, by possible subconcepts (e.g., COVFR can be partitioned into BOTTOM and TOP COVFR). by objective tests when available, and by common word pairs used to communicate their values (e.g., thick-thin, rough-smooth, etc.). To illu strate application of principles, subjective scales, identified by common words, w ere used for analyzing the COVFR concept in commercial, men's suiting fabries. These were then mathematically related to the aesthetic concept of COVER for specific fabrics.-----

A mathematical model for natural fiber crimp is proposed which assumes that the analogy with Timoshenko's theory of bimetal thermostats is valid. Formulas for crimp parameters are derived accordingly. They correctly account for the inverse relationship between crimp and denier which has been shown to exist for wool fibers. Experimental data obtained with fibers related to "Orlon Sayelle" 2 Type 21 fibers support the validity of the assumed model. The crimp model hypothesis leads logically to a helical coil spring model for the spatial configuration of natural crimp of fibers. The actual spatial path of crimp is shown to depend in part on fiber bending and torsion rigidities and environmental constraints. The equations derived by Holdaway, based on the helical coil model, for the force-extension characteristic of natural crimp are shown to be valid for the elastic behavior of crimped fibers in the unerimping regions of the load-elongation curve.

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Geometric torsion and curvature accurately describe three-dimensional forms of crimp. The usual parameters of crimp frequency and indices of amplitude or extensibility for idealized planar or helical crimp forms are expressible by specific relationships of geometric torsion and curvature. The more common, nonideal crimp forms are characterized by distribution statistics of these two fundamental parameters along the fiber. Mathematical techniques and analytical expressions were developed for describing crimp this way with data from an automatic crimp-measuring instrument and use of a digital computer. Examples are given from measurements made on several commercial man-made and natural fibers.

Crimp form of textile fibers is essentially three-dimensional in character. Two parameters, geometric curvature and torsion, accurately describe the space path of fiber crimp. Measurements needed for determination of these parameters are tedious and impractical to obtain by manual methods. An instrument built by Du Pont makes these measurements automatically. It differs from published instrumental techniques by providing data which allow definition of torsion and curvature of crimp as well as the more usual crimp frequency and extensibility parameters. Measurements of a series of fibers shows that fiber crimp, expected to be planar by virtue of mechanical crimping processes, has a three-dimensional character.