Discussion: “A Photoelastic Study of Maximum Tensile Stresses in Simply Supported Short Beams Under Central Transverse Impact” (Betser, A. A., and Frocht, M. M., 1957, ASME J. Appl. Mech., 24, pp. 509–514)

Abstract Simply supported short Castolite beams of uniform rectangular cross section were subjected to central transverse impact by a heavy mass. Photoelastic streak photographs were taken of the transverse section of symmetry for a wide range of spans, widths, and impact velocities at exposures of less than 1 microsec. The maximum tensile stresses were determined. Comparison with the elementary theory for long beams shows that while this theory is satisfactory for long beams, it does not agree with the results from short beams. An approximate theory for short beams under central impact is developed which gives satisfactory agreement. The duration of impact also was determined and the appearance of isotropic points is discussed.

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Transverse Impact of a Damped Plate near a Straight Edge

Journal of Vibration and Acoustics ◽

10.1115/1.2873852 ◽

1995 ◽

Vol 117 (1) ◽

pp. 103-108 ◽

Cited By ~ 6

Author(s):

A. N. Danial ◽

J. F. Doyle

Keyword(s):

Finite Element ◽

Free Edge ◽

Flexural Wave ◽

Viscous Damping ◽

Finite Element Analyses ◽

Edge Waves ◽

Transverse Impact ◽

Reflected Waves ◽

Simply Supported ◽

Flexural Wave Propagation

The effects of boundaries on flexural wave propagation in plates with viscous damping are studied through spectral and finite element analyses of incident and reflected waves. The incident wave is generated by point impact and therefore has the complication of being circularly crested. Results show excellent agreement between finite element and spectral solutions for waves—with high and low damping—reflected from simply supported, clamped and free edges. In addition, the possibility of Rayleigh-type free edge waves are investigated.

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Elastic Transverse Impact on Beams

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.326-328.1559 ◽

2006 ◽

Vol 326-328 ◽

pp. 1559-1562

Author(s):

Dulal Goldar

Keyword(s):

Dynamic Stress ◽

Weight Ratio ◽

Dynamic Strain ◽

Stress Distributions ◽

Transverse Impact ◽

Low Velocity ◽

Structural Element ◽

Simply Supported Beam ◽

Simply Supported ◽

New Findings

Present investigation were carried out to study photoelastically the stress distributions in a simply supported beam with over- hangs subjected to a low velocity central- and quarter- spanimpact loadings by light strikers keeping beam/ striker weight ratio constant (2.675), and then comparing the results so obtained with those in similar simply supported beams made of other materials subjected to central- impact loadings from an analysis of dynamic strain gauge data. Interesting new findings were obtained from the results of the present investigation and also from results reported in the literature in this respect. Introduction. In modern times dynamic stress analysis is becoming increasingly important for various engineering applications. Although significant amount of insight in these respects have been developed, the subject being rather intricate would continue to attract of more research workers in future. A beam is a common structural element, and in several applications, simply supported beams with over- hang are employed in practice. Transverse and longitudinal bridge girders and chassis of rails- and road- wagons are some of the typical applications of the same. Here, photoelastic technique was employed to determine dynamic stress distributions in a model simply supported beam with over- hang.

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Effect of Bimodularity on the Stress State of a Variable Cross-Section Reinforced Beam

Materials Science Forum ◽

10.4028/www.scientific.net/msf.974.646 ◽

2019 ◽

Vol 974 ◽

pp. 646-652

Author(s):

Aleksey N. Beskopylny ◽

Elena Kadomtseva ◽

Vadim Poltavskii ◽

Mikhail Lukianenko

Keyword(s):

Stress State ◽

Cross Section ◽

Rectangular Cross Section ◽

Neutral Line ◽

Variable Cross Section ◽

Variable Cross ◽

Reinforcing Bars ◽

Tensile Stresses ◽

Simply Supported ◽

Compressive Stresses

The article is dedicated to the effect of different modulus of the material on the stress state of a beam of the variable rectangular cross section. The height of the beam varies linearly along its length. Formulas for calculating the maximum compressive and tensile stresses and determining the neutral line are obtained. The maximum tensile and compressive stresses are determined for the clamped and simply supported beams. The dependence of the maximum normal stress on the number of reinforcing bars located in the stretched zones is numerically investigated. The stress state of the beam is compared with and without consideration of the bimodularity of the material for simply supported and cantilever beams. It is shown that taking into account the bimodularity of the material significantly affects the maximum tensile and compressive stresses. The magnitude of the tensile stresses is increased by 30%; the magnitude of the compressive stresses is reduced by 21%. As a bimodular material, fibro foam concrete is considered in work.

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Impact of a Mass on a Column

Journal of Applied Mechanics ◽

10.1115/1.4010012 ◽

1949 ◽

Vol 16 (4) ◽

pp. 370-374

Author(s):

W. H. Hoppmann

Keyword(s):

Elastic Support ◽

Transverse Impact ◽

Numerical Examples ◽

Simply Supported

Abstract In this paper a study is made of the problem of the transverse impact of a mass on a column with simply supported ends. Consideration is also given to the case in which the column has elastic support throughout its length. Formulas are obtained for the deflections and strains. Numerical examples illustrating the theory are worked out in detail.

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Simply supported FPEDs connected by springs for broadband energy harvesting

International Journal of Applied Electromagnetics and Mechanics ◽

10.3233/jae-209323 ◽

2020 ◽

Vol 64 (1-4) ◽

pp. 201-210

Author(s):

Yoshikazu Tanaka ◽

Satoru Odake ◽

Jun Miyake ◽

Hidemi Mutsuda ◽

Atanas A. Popov ◽

...

Keyword(s):

Energy Harvesting ◽

Evaluation Method ◽

Energy Harvester ◽

Vibrational Energy ◽

Functional Materials ◽

Vibration Energy ◽

Theoretical Evaluation ◽

Vibration Energy Harvester ◽

Polyvinylidene Difluoride ◽

Simply Supported

Energy harvesting methods that use functional materials have attracted interest because they can take advantage of an abundant but underutilized energy source. Most vibration energy harvester designs operate most effectively around their resonant frequency. However, in practice, the frequency band for ambient vibrational energy is typically broad. The development of technologies for broadband energy harvesting is therefore desirable. The authors previously proposed an energy harvester, called a flexible piezoelectric device (FPED), that consists of a piezoelectric film (polyvinylidene difluoride) and a soft material, such as silicon rubber or polyethylene terephthalate. The authors also proposed a system based on FPEDs for broadband energy harvesting. The system consisted of cantilevered FPEDs, with each FPED connected via a spring. Simply supported FPEDs also have potential for broadband energy harvesting, and here, a theoretical evaluation method is proposed for such a system. Experiments are conducted to validate the derived model.

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