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Basic Theory of Plates and Elastic Stability - Part 21

Tài liệu tham khảo giáo trình cơ học kết cấu trong ngành xây dựng bằng Tiếng Anh - Yamaguchi, E. “Basic Theory of Plates and Elastic Stability” Structural Engineering Handbook Ed. Chen Wai-Fah Boca Raton: CRC Press LLC, 1999 - Basic Principles of Shock Loading | Blodgett O.W. and Miller D.K. Basic Principles of Shock Loading Structural Engineering Handbook Ed. Chen Wai-Fah Boca Raton CRC Press LLC 1999 Basic Principles of Shock Loading 21.1 Introduction O.W. Blodgett and D.K. Miller The Lincoln Electric Company Cleveland OH 21.2 Requirements for Optimum Design 21.3 Absorbing Kinetic Energy 21.4 Material Properties for Optimum Design 21.5 Section Properties for Optimum Design 21.6 Detailing and Workmanship for Shock Loading 21.7 An Example of Shock Loading 21.8 Conclusions 21.9 Defining Terms References Further Reading 21.1 Introduction Shock loading presents an interesting set of problems to the design engineer. In the engineering community design for static loading traditionally has been the most commonly used design procedure. Designing for shock loading however requires a change of thinking in several areas. The objectives of this discussion are to introduce the basic principles of shock loading and to consider their effect upon the integrity of structures. To understand shock loading one must first establish the various loading scheme definitions. There are four loading modes that are a function of the strain rate and the number of loading cycles experienced by the member. They are the following static loading fatigue loading shock loading shock fatigue combination loading Static loading occurs when a force is slowly applied to a member. This is a slow or constant loading process that is equivalent to loading the member over a period of 1 min. Designing for static loading traditionally has been the approach used for a wide variety of components such as buildings water towers dams and smoke stacks. Fatigue loading occurs when the member experiences alternating repeated or fluctuating stresses. Fatigue loading generally is classified by the number of loading cycles on the member and the stress level. Low cycle fatigue usually is associated with stress levels above the yield point and fracture initiates in less than 1000