A theoretical analysis of the dynamic response of metallic sandwich beam under impulsive loading

A bidirectional functionally graded Sandwich (BFGSW) beam model made from three distinct materials is proposed and its dynamic behavior due to nonuniform motion of a moving point load is investigated for the first time. The beam consists of three layers, a homogeneous core, and two functionally graded face sheets with material properties varying in both the thickness and longitudinal directions by power gradation laws. Based on the first-order shear deformation beam theory, a finite beam element is derived and employed in computing dynamic response of the beam. The element which used the shear correction factor is simple with the stiffness and mass matrices evaluated analytically. The numerical result reveals that the material distribution plays an important role in the dynamic response of the beam, and the beam can be designed to meet the desired dynamic magnification factor by appropriately choosing the material grading indexes. A parametric study is carried out to highlight the effects of the material distribution, the beam layer thickness and aspect ratios, and the moving load speed on the dynamic characteristics. The influence of acceleration and deceleration of the moving load on the dynamic behavior of the beam is also examined and highlighted.

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Dynamics of Closed Circuit Hydraulic Model Loops

Volume 1: Fora, Parts A and B ◽

10.1115/fedsm2002-31003 ◽

2002 ◽

Cited By ~ 1

Author(s):

Bjo̸rnar Svingen ◽

Morten Kjeldsen ◽

Roger E. A. Arndt

Keyword(s):

Theoretical Analysis ◽

Dynamic Response ◽

Theoretical Work ◽

Current Theory ◽

Water Tunnel ◽

Post Processing ◽

Global System ◽

Pressure Transducers ◽

Response Data ◽

Cavitating Hydrofoil

This paper reviews the issue of making unsteady measurements involving cavitating flow in traditional test loops. Measurements of the dynamic response of a water tunnel during testing of a partially cavitating hydrofoil are presented and reviewed in the context of current theory. Data were collected from an array of pressure transducers that were distributed around the tunnel loop. In the post processing of these data, gain and phase response data were calculated. Theoretical analysis consisted of splitting the system into different elements, and included the compressibility of water in the physics used to describe each element. While solving the global system an eigenvalue solution was found, thus no node specific solution is obtained. This work is currently being extended with the aim of obtaining node specific values such that a more direct comparison between the experimental and theoretical work can be made.

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Impulsive Forming of Shell Structures With Apertures

Applied Mechanics and Biomedical Technology ◽

10.1115/imece2003-41811 ◽

2003 ◽

Author(s):

V. Sabelkin

Keyword(s):

Dynamic Response ◽

High Explosive ◽

Impulsive Loading ◽

Shell Structures ◽

Plastic Properties ◽

Aperture Diameter ◽

Jet Engine ◽

Explosive Charges ◽

Explosive Forming ◽

Static And Dynamic Loading

Different modern shell structures are exposed to impulsive loading very often. Some of them may have different imperfections such as apertures, welds, and irregular thickness. These structures can be made by static or impulsive loading. To know fractureless dynamic response of shell structures with apertures is important in many cases, especially for forming processes, because of the first appeared fracture can extend through a shell blank especially if material is brittle with low plastic properties. The tooling for impact and static loading of flat and shell structures was developed. Dynamic response of shell structures with unsupported apertures on internal impulsive loading by point high explosive charges is described. Strain state of shaped shell structures with apertures after explosive forming is shown. The limit aperture diameter for dynamic fractureless response is determined. Distributions of strain intensities on a sample cross section for different aperture diameters, static and dynamic loading are shown. Different jet engine parts were made using developed technology.

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