Bending moment

About: Bending moment is a research topic. Over the lifetime, 14577 publications have been published within this topic receiving 158834 citations. The topic is also known as: bending moment.

Drying creep of concrete: constitutive model and new experiments separating its mechanisms

Abstract: A new experimental method which allows the direct separation of the components of drying creep due to microcracking and stress-induced shrinkage is developed, demonstrated and validated. The basic idea is to compare the curvature creep of beams subjected to the same bending moment but very different axial forces. The results confirm that drying creep has two different sources: microcracking and stress-induced shrinkage. The latter increases continuously, whereas the former first increases and then decreases. The test results are fitted using a finite element model. The results validate the present model for drying creep. The microcracking is described by an established model, and the free (unrestrained) shrinkage of a material element is shown to depend approximately linearly on the humidity drop.

Shear correction factors for plates and shells

Abstract: Multilayered plate and shell finite elements usually have a constant shear distribution across the thickness. This causes a decrease of accuracy, especially for sandwich structures. The problem is overcome by using shear correction factors which are defined by energy considerations. In this paper a study on shear correction factors is presented as well as typical applications. These factors are defined by studying a crossply laminate without midplane symmetry in cylindrical bending. It is possible to define one factor for a given cross section or several ones, one factor per ply. The two ways are equivalent. Special cases are studied: a multilayered plate, a symmetrical sandwich and a structure formed by two plates glued to each other. The importance of shear correction factors is illustrated in the case of plate and shell applications; the results are obtained by using three-dimensional degenerated shell finite elements.

Fiber Element for Cyclic Bending and Shear of RC Structures. I: Theory

Abstract: After a few years of successful application of the fiber beam element to the analysis of reinforced concrete (RC) frames, the introduction of the mechanisms of shear deformation and strength appears to be the next necessary step toward a realistic description of the ultimate behavior of shear sensitive structures This paper presents a new finite-beam element for modeling the shear behavior and its interaction with the axial force and the bending moment in RC beams and columns This new element, based on the fiber section discretization, shares many features with the traditional fiber beam element to which it reduces, as a limit case, when the shear forces are negligible The element basic concept is to model the shear mechanism at each concrete fiber of the cross sections, assuming the strain field of the section as given by the superposition of the classical plane section hypothesis for the longitudinal strain field with an assigned distribution over the cross section for the shear strain field Transve

The Importance of Body Stiffness in Undulatory Propulsion

Abstract: During steady swimming in fish, the dynamic form taken by the axial undulatory wave may depend on the bending stiffness of the body. Previous studies have suggested the hypothesis that fish use their muscles to modulate body stiffness. In order to expand the theoretical and experimental tools available for testing this hypothesis, we explored the relationship between body stiffness, muscle activity, and undulatory waveform in the mechanical context of dynamically bending beams. We propose that fish minimize the mechanical cost of bending by increasing their body stiffness, which would allow them to tune their body's natural frequency to match the tailbeat frequency at a given swimming speed. A review of the literature reveals that the form of the undulatory wave, as measured by propulsive wavelength, is highly variable within species, a result which calls into question the use of propulsive wavelength as a species-specific indicator of swimming mode. At the same time, the smallest wavelength within a species is inversely proportional to the number of vertebrae across taxa ( r 2 = 0.21). In order to determine if intact fish bodies are capable of increasing bending stiffness, we introduce a method for stimulating muscle in the body of a dead fish while it is being cyclically bent at physiological frequencies. The bending moment (N m) and angular displacement (radians) are measured during dynamic bending with and without muscle stimulation. Initial results from these whole body work loops demonstrate that largemouth bass possess the capability to increase body stiffness by using their muscles to generate negative mechanical work.