ABSTRACT
I. Introduction 430
II. Paper Failure 430
III. Fracture Mechanics 433 A. Stress Concentrations 434 B. Linear Elastic Fracture Mechanics 436 C. Elastic-Plastic Fracture Mechanics 446 D. Measuring Jc 448 E. Making Failure Predictions Using Jc 450 F. Essential Work of Fracture 450 G. Measuring we 451 H. Making Failure Predictions with we 451 I. Summary 452
IV. Fracture of Dry Paper and Board 453 A. Introduction 453 B. Elmendorf Tear 453 C. In-Plane Tear 456 D. Tensile Energy Absorption 458 E. Linear Elastic Fracture Mechanics 460 F. ./-Integral 463 G. Essential Work of Fracture 465 H. Conclusions 467
V. Applications of Fracture Mechanics 468 A. Runnability of Newsprint 469 B. Bag Drop 474
C. Crease Cracking/Die Cutting 474
VI. Conclusions
Appendix Kj Solutions for Simple Specimen Configurations
References
I. INTRODUCTION
Fracture mechanics is the field of applied mechanics that deals with the prediction of crack initiation and propagation in solid materials. Fracture mechanics provides for a quantitative prediction of fracture loads in cracked structures. It also provides a foundation for the design of fracture-resistant materials [1]. In its most general sense the term “fracture mechanics” applies to any study of material fracture, but over the past 40 years, it has come to refer more specifically to the study of crack propagation based on the fracture criterion derived by A. A. Griffith [2].
