Biomechanical Engineering of Textiles and Clothing

Yan Li, D X-Q Dai

• Publisher: Woodhead Publishing
• Year: 2006
• Print ISBN: 9781845690526
• eBook ISBN: 9781845691486
• Topic: Technology & Engineering
• Subtopic: Materials Science
• Index: Technology & Engineering

Biomechanical engineering enables wearers to achieve the highest level of comfort, fit and interaction from their clothing as it is designed with the mechanics of the body in mind. This enables products to be developed that are specifically designed for the mechanics of their end purpose (e.g. sports bra) as well as the everyday movement of the body. This is the first book to systematically describe the techniques of biomechanical engineering principles, methods, computer simulation, measurements and applications.Biomechanical engineering of textiles and clothing addresses issues of designing and producing textiles and clothing for optimum interaction and contact with the body. It covers the fundamental theories, principles and models behind design and engineering for the human body's biomechanics, contact problems arising between textiles/clothing and the body and the mechanics of fibres, yarns, textiles and clothing. Material properties are discussed in relation to mechanical performance. It also includes coverage of the Clothing Biomechanical Engineering System developed at The Hong Kong Polytechnic University and its associated models and databases. The book concludes with practical examples of clothing applications to illustrate how to carry out biomechanical engineering design for specific applications. - Addresses issues of designing and producing textiles for interaction and contact with the body - Covers fundamental theories, principles and models behind design and engineering - Contains practical examples of clothing applications to illustrate biomechanical engineering design for specific applications

Part I

Introduction

1

Textile biomechanical engineering

Y. Li¹; X. Zhang²; X.-Q. Dai^{1,3 1} The Hong Kong Polytechnic University, China
² Xian University of Engineering Science & Technology, China
³ Soochow University, China

1.1 Background

Health and disease-prevention have been and are of major concern to humans, particularly for 21st century consumers regarding their apparel products. Biological health and psychological happiness are critical indexes reflecting quality of life, in which clothing plays very important roles. Clothing is one of the most intimate objects associated with the daily life of individuals, as it covers most parts of our body most of the time. Consciously or unconsciously, our physiological/biological status and psychological/emotional feelings are closely associated with the clothing we wear. A significant proportion of modern consumers understand the importance of clothing and they demand apparel products with higher added values in terms of functional performance to satisfy various aspects of their biological and psychological needs in communication, protection, healthcare, medicine and sensory comfort during wear. Naturally, engineering apparel products for biological and psychological health has become an integrated part of the concept of bioengineering.

What, then, is bioengineering? In February 1998, the United States National Institutes of Health organized a Symposium on bioengineering, at which a definition of bioengineering was formulated as follows: ‘Bioengineering integrates physical, chemical, or mathematical sciences and engineering principles for the study of biology, medicine, behavior, or health. It advances fundamental concepts, creates knowledge from the molecular to the organ systems level, and develops innovative biologics, materials, processes, implants, devices, and informatics approaches for the prevention, diagnosis, and treatment of disease, for patient rehabilitation, and for improving health’.¹

Angnew pointed out that bioengineering is rooted in physics, mathematics, chemistry, biology, computational sciences, and various engineering disciplines.¹ It is the application of a systematic, quantitative and integrative way of thinking about and approaching solutions of problems important in human biology, physiology, medicine, behavior and health of human populations. From this definition, it is clear that the biological problems are too complex to be solved by biologists alone: partners are needed in many disciplines, including physics, mathematics, chemistry, computer sciences, and engineering. Bioengineering integrates principles from a diversity of fields. The creativity of interdisciplinary teams results in a new basic understanding, novel products and innovative technologies. Bioengineering also crosses the boundaries of academia, science, medicine, and industry.

Considering that clothing has a significant impact on the health and prevention of diseases, and creating appropriate microclimates for living and appearances that influence the perceptions and behaviors of human beings, clothing bioengineering can be defined in a similar way: ‘Clothing bioengineering integrates physical, chemical, mathematical, and computational sciences and engineering principles to design and engineer clothing for the benefits of human biology, medicine, behavior and health. It advances fundamental concepts; creates knowledge from the molecular to the body–clothing systems level; and develops innovative materials, devices, and apparel products for a healthy lifestyle fashion with functions of comfort, protection, prevention, diagnosis, and treatment of disease, and for improving health.’

Such a definition shows that clothing bioengineering is rooted in physics, mathematics, chemistry, polymer sciences, biology, computational sciences, and engineering disciplines in polymers, fibers, textiles and clothing. It is the application of a systematic, quantitative and integrative way of thinking about and approaching the solutions in problems of how clothing and textiles can be engineered to the benefits of biology, physiology, medicine, behavior and the health of human populations. From this definition, it is clear that clothing bioengineering needs knowledge and close collaborative research of experts from a diversity of fields, including physics, mathematics, chemistry, polymer science, computer sciences, biology, physiology and psychology, as well as engineering disciplines from such industries as polymer, fiber, textile and clothing. The creativity of interdisciplinary teams can result in new basic understanding, novel products and innovative technologies in a number of areas such as: (i) clothing bio-thermal engineering; (ii) clothing biomechanical engineering; (iii) clothing biosensory engineering; (iv) clothing biomedical engineering; and (v) clothing biomaterial engineering.

Clothing biomechanical engineering is defined as the application of a systematic and quantitative way of designing and engineering apparel products to meet the biomechanical needs of the human body and to maintain an appropriate pressure and stress distributions on the skin and in the tissues for the performance, health and comfort of the wearer. Clothing biomechanical engineering involves not only the design and engineering of fabrics, but also the measurement of body geometric profiles, and the design and engineering of garments to achieve the required biomechanical functions. Fundamental research to achieve the biomechanical functions involves a number of areas: (i) development of theories, data and models to describe the mechanical behaviors of fiber, yarns and fabric; (ii) development of theories, data and models to describe the geometric and biomechanical behavior of the human body; (iii) development of theories, data and models to describe the dynamic mechanical interactions between the body and garments; (iv) development of computational methods, computing visualization techniques, and engineering databases to integrate all the elements systematically; (v) design and engineering of materials and clothing to achieve desirable biomechanical functions; (vi) development of techniques to characterize the biomechanical functional performances from basic materials to final apparel products.

1.2 History of clothing biomechanical engineering design

Engineering design is an iterative decision-making process in which the basic sciences, mathematics, and engineering sciences are applied to convert resources optimally to meet a stated objective.² It is the link between scientific discoveries and commercial applications by applying mathematics and science to research and to develop economical solutions to practical technical problems. Engineering design has been successfully applied in a number of engineering areas such as machine manufacturing, civil engineering, and bridge construction. In 1986, the concept of sensory-engineering (Kansei-engineering) was developed by the Mazda Company in Japan as a development of human factors. Sensory means the psychological feeling or image of a product, and sensory engineering refers to the quantitative translation of consumers’ psychological feeling about a product into perceptual design elements. This technique involves determining which sensory attributes elicit particular objective responses from people, and then designing a product using the attributes that elicit the desired responses. Sensory engineering has been applied with great success in the automotive industry, the Mazda Miata (MX-5) being a notable example, and is being extended to other product domains including development of new fibers.³

Textile products have been designed by trial and error for thousands of years. However, in the last few decades, industrial and academic experts⁴⁻⁹ have recognized the importance of systematic engineering design of textiles and textile processes. In 1994, Hearle⁷ presented the concept of textile-product design with fabric mechanics as a design tool. He described the different approaches available to tackle fabric mechanics in a hierarchical way and developed the concept of a computer-aided total-design system based on three frameworks: a database of information on fiber and fabric properties; a knowledge-based system using the pool of available expertise and historical data; and a deterministic suite of programs in structural mechanics. In the 1990s, Matsuo and Suresh⁸ proposed the concept of fiber-assembly-structure engineering (FASE) for total material design. Total material design refers to the design of a textile product starting from the conceptual design and going up to the devising of the manufacturing method. The design has three stages: (i) aesthetic-effect or functional design; (ii) basic structure design; (iii) basic manufacturing design.

The close relationship between garment design and fabric selection means that fabric representation and design is a fundamental part of any clothing engineering design system. Fabric is a complex media to model, owing to its complicated microstructure. In the past two decades, cloth modeling has drawn wide attention both from the textile engineering and the computer graphics communities. The textile engineering approach concentrated on the relationship between fabric structure and measurement data. In the 1990s, a series of papers by Dastor et al.^4,10,11 presented the computer-assisted structural design of industrial woven fabric, which illustrated the possibility of creating a CAD environment to aid structural design and evaluation of industrial fabric economically. The goal is the engineering design of the ideal quality of suiting on the basis of fiber science, textile mechanics and the objective measurement technology developed. Today, there are numerous existing design programs with various software tools and a wide choice of design functions. For example, Lectra¹² and NedGraphic¹³ offer the textile industry a range of CAD/CAM software packages to meet the different requirements of various woven and knitted fabrics, printed fabrics and garment design. However, in such software, the focus is the image effects rather than the geometrical and mechanical models of fabrics and garments. Many existing apparel CAD systems provide assistance in pattern design, grading, marker making and cutting processes. Most of the systems work only two-dimensionally, and the materials’ mechanical behavior is not taken into account.¹⁴

While the textile engineering approach offers precise details of modeling cloth at a microscopic level,¹⁵ the computer graphics approach treats fabric as a deformable object, to develop visually-realistic cloth deformation and animation. Clothing modeling and garment simulation has grown from basic shape modeling to the modeling of cloth complex physics and behaviors. A trend of employing a multidisciplinary approach has started, the two communities having begun to combine their expertise to come up with solutions that can satisfy both of them. With their efforts, 2D apparel CAD systems are extending to 3D. A 3D apparel CAD system often incorporates a suitable fabric model, and enables the designer to assess how a particular type of fabric would interact with the 3D body form. The fabric model may include links to objective data and surface visualization techniques which allow a fabric design or structure to be superimposed on the garment. Rodel et al.¹⁴ pointed out that an excellent CAD system for the clothing industry should comprise three modules: a fabric library relating easy-to-determine fabric mechanical properties; a 3D model for the human body, which can be adapted for people of different sizes; and routines to construct garments from 2D patterns of specific fabrics on the human body with use of the fabric library. A common approach to constructing a garment is to accept 2D pattern shapes from a conventional CAD system, assemble them into a garment and drape or fit it onto a body form for further assessment and adjustment.

Early in 1992, Okabe et al.¹⁶ presented details of a 3D CAD system with an energy-based fabric modeler incorporated. They showed examples of simulated garments fitted on a mannequin. The Asahi¹⁷ apparel CAD 3D-PDS system, released in 1995, was also a 3D system that allowed designers to model patterns incorporating a fabric stiffness parameter. Both these systems accept the mechanical properties of fabrics. More recently, Kang and King^18,19 presented details of their 3D apparel system including flat- garment pattern generation, resizable human body modeling and garment- drape shape prediction. There was no evidence that actual mechanical parameters of fabric were used. The computer graphic community seems to be more advanced in 3D clothing modeling. There are many virtual fashion systems developed by different research teams from the computer graphics area, such as the Virtual try on system from the Miralab team (Geneva), DressingSim from Digital Fashion Ltd (Japan), and ‘MayaCloth’ from Maya, Spain. Most of these systems focus on generating cloth-like simulation and quick response and animation; accurate interpretation of mechanical properties and real-time performance are of secondary importance.

Although a 3D human body model is essential in all 3D apparel CAD systems, it is often assumed to be rigid, and acts as a geometrical constraint for the garment to drape or closely fit on it. The body deformation due to contact with the garment is rarely taken into account. Modern consumers demand clothing products w...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright page
• Contributor contact details
• Part I: Introduction
• Part II: Theoretical background
• Part III: Material properties
• Part IV: Clothing biomechanical engineering design (CBED) system
• Part V: Applications in product development
• Index