Tham khảo tài liệu 'volume 08 - mechanical testing and evaluation part 13', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Fatigue Testing of Brittle Solids . Salem Glenn Research Center at Lewis Field . Jenkins University of Washington Summary Fatigue testing of ceramics and glasses is performed by either indirect or direct methods. Indirect or strength methods employ smooth tensile or flexure specimens and infer the fatigue parameters from strength measurements without crack length measurements. Direct methods employ either long cracks or short cracks and the crack length is measured by observation of the crack or by inference from devices such as strain gages and electrical resistance grids. Long crack test specimens include fracture mechanics specimens such as the DT DCB CT and SEPB. Short crack methods employ surface cracks formed by indentation or surface cracks that develop naturally on the surface of a smooth test specimen. Structural ceramic and glass components that are designed to have long lives will fail from small cracks developed over long periods of time. The cracks will develop from either inherent processing flaws or from damage generated in component machining and handling . machining cracks . Cyclic loading though not required to induce growth in glasses and many ceramics tends to accelerate fatigue crack growth. Thus the measurement of fatigue parameters should be done with tests employing realistic crack sizes environments and the applicable load histories. As a result the development of standardized static and cyclic fatigue test methods has revolved around the use of small inherent flaws. Fatigue Testing of Brittle Solids . Salem Glenn Research Center at Lewis Field . Jenkins University of Washington References 1. C. Gurney and S. Pearson Fatigue of Mineral Glass under Static and Cyclic Loading Proc. R. Soc. A. Vol 192 1948 p 537-543 2. . Shand Experimental Study of Fracture of Glass Part I The Fracture Process J. Ceram. Soc. Vol 37 1954 p 52-60 3. S. Pearson Delayed Fracture of Sintered Alumina Proc. Physicl Soc. Vol 69 Part 12 Section B Dec .
