Search Results for transverse compression

Damping is the energy dissipation properties of a material or system under cyclic stress. The vibrational and damping characteristics of composites are important in many applications, including ground-based and airborne vehicles, space structures, and sporting goods. This article describes the damping characteristics of unidirectional composites, when they are subjected to longitudinal shear, longitudinal tension/compression, and transverse tension/compression. It presents equations that govern the overall damping capacity of beams that are cut from laminated plates. The article discusses the effect of temperature on damping and provides information on the relationship between damping and strength.

This article explores why structural element and subcomponent testing are conducted. It discusses the different types of failure modes in composites, and provides information on the testing methodology, fixturing, instrumentation, and data reporting. The article reviews various standard elements used to characterize composite materials for the various failure modes. Simple structural-element testing under in-plane unidirectional, multidirectional, and combined loading, as well as out-of-plane loading are discussed. Simple bolted and bonded joints, as well as data correlation are reviewed with analytical predictions. The article also provides a list of the ASTM testing standards applicable at the element level of testing for both polymer-matrix composites and metal-matrix composites. It concludes with a discussion on durability and damage tolerance testing.

This article describes several factors, which help in determining the compressibility of metal powders: particle shape, density, composition, hardness, particle size, lubrication, and compacting. It discusses the uses of annealing metal powders and describes compressibility testing of the powders. The article details green strength and its mechanism and the variables affecting the strength. It also discusses two test methods for determining the green strength: the Rattler test and the transverse bend test.

This article presents a comprehendable and comprehensive physics-based approach for characterizing the strength of fiber-reinforced polymer composites. It begins with background information on the goals and attributes of this method. The article then addresses the characterization of fiber failures in laminates, because these are at the highest strengths that can be attained and, therefore, are usually the design objective. An exception would be if the design goal is to maximize energy absorption, rather than static strength. The discussion proceeds to situations in which the matrix fails first, either by intent, by design error, or because of impact damage. The state of the modeling propagation and arrest of matrix damage follows. Comparisons of this physics-based approach are then made to empirically based failure theories.

This article describes the formation of residual stresses and distortion, providing information on the techniques for measuring residual stresses. It presents a detailed discussion on the magnitude and distribution analysis of the residual stresses and distortion in weldments. The article briefly explains the effects of residual stresses and distortion on the brittle fracture and fatigue fracture of welded structures. It also provides information on the thermal treatments of weldments.

This article describes the results of several case history studies of the failure of polymer-matrix composite components to provide not only some representative types of failures that can encounter, but also to provide some insight into the investigative process. These case histories deal mainly with structures that exhibit an initial material and/or manufacturing defect or failures that are most prevalent and most easily solved. The components include helicopter rotor blade, composite wing spar, and aircraft rudder.

This article describes the formation of residual stresses and distortion and the techniques for measuring residual stresses. It provides a discussion on the magnitude and distribution analysis of residual stresses and distortion in weldments. The article considers the effects of residual stresses and distortion on the brittle fracture and fatigue fracture of welded structures. The thermal treatments of weldments are also discussed.

A sandwich structure is comprised of layered composite materials formed by bonding two or more thin facings or facesheets to a relatively thick core material. This article describes the sandwich panel failure modes. It tabulates the nomenclature and definitions for loads, geometry, and material properties. The article illustrates critical strength-check locations for a flat sandwich panel. It discusses the analysis methods formulated for flat rectangular honeycomb panels; curved sandwich panel; and for each of the various sandwich panel failure modes. The article concludes with a discussion on flat panel stability analysis methods.