Product Fit and Sizing by Robinette, Kathleen M.; Veitch, Daisy; Alemany, Sandra; Bredenkamp, Karen;

Short description:

This book addresses the complexity of assessing fit and using fittings in the product design process from a scientific and systems engineering perspective. Including: how to represent the anthropometry of the target market, good practices for reliable fit testing, and comprehensive statistical analyses for fit and sizing analysis.

Long description:

In this book, for the first time, the complexity of assessing fit and using fittings in the product design process is addressed from a scientific and systems engineering perspective. It includes methods to represent the anthropometry of the target market, good practices to develop protocols for more reliable and consistent fit testing, methods for developing and maintaining a fit database, comprehensive statistical analyses needed for fit and sizing analysis, and instructions for selecting and modeling cases for new product development.

Product Fit and Sizing: Sustainable Product Evaluation, Engineering, and Design offers step-by-step instructions for the evaluation, engineering, and design of existing and new products and includes real-world examples of mass-produced apparel, head wearables, and footwear products. It also explains how to develop a sustainable fit standard for fit and sizing continuity for all styles across all seasons and iterations.

This book is intended for industry professionals and undergraduate and graduate education to prepare students for design and engineering jobs. For organizations that purchase uniforms or protective equipment and apparel, it also provides instructions for purchasing professionals to evaluate the suitability of wearable products for their population.

The Open Access version of this book, available at http://www.taylorfrancis.com, has been made available under a Creative Commons Attribution-Non Commercial-No Derivatives (CC-BY-NC-ND) 4.0 license.

Table of Contents:

Chapter 1 Introduction 1

Abstract 1
Sustainable Product Evaluation, Engineering and Design Process (SPEED) 3
Inputs 6
Design loop 7
Sizing loop 8
How to use this book 13

Chapter 2 Inputs and Getting Started 16

Abstract 16
Products 17
Requirements and Constraints 17
Design Concept 21
Resources 24
Tools 24
Analysis & data management tools 25
Questionnaires 29
Anthropometry 35
Manual tool assessment 42
Imaging tool assessment 45
Physical fit measuring tools 57
Personnel and facilities 61
Personnel 61 Facilities 67
Use of human subjects 67
Test site considerations 68
Target population (TP) sampling and planning 70
Starting TP Sample 71
Planning full TP sample 77
Weighting samples 84
What can go wrong 86

Chapter 3 Cases and Fit Models 91

Abstract 91
Selecting cases 93
Selecting cases with raw data 98
Base size and base size case 105
Multiple cases 119
PCA alternative for selecting key variables 126
Selecting cases with aggregate data 135
Using cases to create mock-ups and prototypes 143
Physical manikins 148
Digital manikins 154
Original point cloud 157
Surfaced manikin 157
Watertight surfaced manikin 157
Standardized homologous watertight manikin 158
Parameterized database manikin 158

Chapter 4 Testing and Analysis Procedures 166

Abstract 166
Experimental design 169
Analysis methods 174
Student’s t-test 176
Paired t-test (repeated measures with 2 treatments) 180
Wilcoxon signed-rank test 181
Wilcoxon rank-sum test (Mann Whitney test) 182
Proportion test 182
Chi-squared test for independence 184
Bivariate correlation 185
General Linear Models 185
Analysis of variance (ANOVA) 188
Linear regression/stepwise linear regression 189
Discriminant analysis 191
Logistic regression 193
Design loop tests and analysis 196
Pilot tests 197
Stand-alone trade studies 198
Comparison of two treatments using paired test design 200
Comparison of two treatments using independent samples 202
Comparison of three or more treatments using repeated measures design 202
Comparison of three or more treatments using independent measures design 205
Prototype fit tests 205
Scenario 1: First prototype iteration with just one size 209
Scenario 2: Existing product with fit and sizing issues in multiple sizes 211

Sizing loop tests and analysis 219
Evaluating the cost versus benefit of sets of sizes 221
Determining the tariff 223
Size prediction 228

Chapter 5 Mass Produced Apparel 231

Abstract 231
Background 231
Fit audit and the Sustainable Fit Standard 233
Grading and the Sweetspot 236
Benefits of the SPEED process 239
Case studies 239
Case study 1: Manufacturer / retailer design, sizing, tariff, & fit standard development 240
Case study 2: Assessment for purchasing an existing product aided by 3D scanning 252
Case study 3: Assessment for purchasing tariff 256
Case study 4: Prototype test to determine the correct alteration 262

Chapter 6 Head and Face Wearables 268

Abstract 268
Background 268
Center of mass vs neck strain 270
Sensitivity to temperature 271
Head orientation and alignment 272
Head anthropometry 281
Case studies 286
Case study 1: Design loop testing of a head wearable to demonstrate use of product based head orientation 286
Case study 2: Design loop testing with a non-functioning mockup including early COF 290
Case study 3: Design loop updates in COF 304
Case study 4: A trade study to investigate temple band closing force 309
Case study 5: Design loop evaluation tools highlighting inputs to design changes 32
Case study 6: Importance of fit testing to predict sizing numbers for purchasing 331

Chapter 7 Footwear 339

Abstract 339
Background 339
Issues with different footwear types 343
Dress shoes and casual footwear 344
Safety, protective, and occupational footwear 349
Sports footwear 351
Key Performance Indicators (KPIs) 352
Concept-of-Fit (COF) 355
Subject assessment 355
The Sustainable Fit Standard 358
Target user profile 359
Foot anthropometry and anatomy 360
Foot as a static structure 361
The dynamics of the foot 363
Foot anthropometry methods 367
Variability of the of the foot anthropometry: sex, age, demographics 371
Resources, planning, and preparation 376
Case studies 379
Case study 1: The design loop of casual and fashion footwear 379
Case study 2: Application to footwear innovation 389

Glossary 391

Index 403