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Wednesday, November 4, 2020 | History

3 edition of Predicted and measured strain responses of isotropic panels to base excitation found in the catalog.

Predicted and measured strain responses of isotropic panels to base excitation

Predicted and measured strain responses of isotropic panels to base excitation

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  • 6 Currently reading

Published by National Aeronautics and Space Administration, Scientific and Technical Information Division, For sale by the National Technical Information Service] in [Washington, D.C.], [Springfield, Va .
Written in English

    Subjects:
  • Strains and stresses.,
  • Structural dynamics.

  • Edition Notes

    StatementKaren H. Lyle, Jack D. Leatherwood and Edward F. Daniels.
    SeriesNASA technical memorandum -- 4054., AVSCOM technical memorandum -- 88-B-013., AVSCOM technical memorandum -- 88-B-13.
    ContributionsLeatherwood, Jack D., Daniels, Edward F., United States. National Aeronautics and Space Administration. Scientific and Technical Information Division.
    The Physical Object
    FormatMicroform
    Pagination1 v.
    ID Numbers
    Open LibraryOL15283777M

    (c) Strain-rate and stress versus time for a Ti 2 AlC specimen loaded at strain-rate of ~ s Figure a) Axial strain versus time signals measured from strain gage sensors (orange) and averaged from DIC analysis (blue) at 3 x s The strain at which cracking occurs is indicated in the plot. Special equipment drivers often suffered from vibration which threatened their physical and mental health. In order to study the riding comfort of a special equipment cab, a hammering experiment has been carried out on it by acceleration sensors. According to the test results, the natural frequency has been calculated which was compared with the result analysis by the Cited by: 2. Cardiac excitation and contraction have previously been modeled in our laboratory on global representations of cardiac anatomy using the finite element numerical solution technique. 19 In the present study, we extend this approach to investigate how excitation processes could be influenced by structure at a much finer scale. We extracted an. The predicted liquefaction resistances using Eqs. and, i.e., the dotted lines in Fig. 11, and the measured liquefaction resistances, i.e., the solid lines in Fig. 11, are plotted as solid circles in Fig. Comparison of the predicted and measured liquefaction resistances confirms the accuracy of the wave correction coefficient, c α.


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Predicted and measured strain responses of isotropic panels to base excitation Download PDF EPUB FB2

Accelerations were measured on the base and at one panel location for both the cantilevered and the C-F-C-F panels. Predictions were based on the Ritz method with assumed beam functions.

The measured accelerations of the base and modal damping values were input to the analysis. Measured and predicted modal frequencies agree to within 4 percent. Get this from a library. Predicted and measured strain responses of isotropic panels to base excitation.

[Karen H Lyle; Jack D Leatherwood; Edward F Daniels; United States. National Aeronautics and Space Administration. Scientific and Technical Information Division.]. The strains were measured at 9 locations on the cantilevered panels and at 5 locations on the C-F-C-F panels.

Predictions were based on the Ritz method. The measured accelerations of the base were input to the analysis for the forcing function. NASA Technical Memorandum AVSCOM Technical Memorandum B NASA-TM Predicted and Measured Strain Responses of Isotropic Panels to Base Excitation upa^l £$^ Karen H.

Lyle, Jack D. Leatherwood, and Edward F. Daniels AUGUST For b^^., y *^ Chilly C£ ^ TTo ^u^ v FB OMnu3 BOOM NASA US ARMY AVIATION SYSTEMS. Predicted and measured strain responses of isotropic panels to base excitation / By Karen H. Lyle, Edward F. Daniels, Jack D.

Leatherwood and United States. National Aeronautics and Space Administration. Scientific and Technical Information Division. Abstract "August "es bibliographical references (p. ).Mode of access. Predicted and measured strain responses of isotropic panels to base excitation / (Washington, D.C.: National Aeronautics and Space Administration, Scientific and Technical Information Division, ), by Karen H.

Lyle, Edward F. Daniels, Jack D. Leatherwood, and United States. National Aeronautics and Space Administration. Part of the Review of Progress in Quantitative Nondestructive Evaluation book series (RPQN, volume 18 A) Abstract The near field dynamic response of a quasi-isotropic laminate to a number of impulsive internal line sources has been considered in the companion paper [1].Author: E.

Rhian Green, W. Green. The dynamic response characteristics of an operational single pile platform are investigated in detail.

Wind, wave, and response time histories recorded on the platform in Marchform the basis for comparison of predicted and measured dynamic response.

In the predictive analysis, the components of the total modal damping are separately Cited by: 9. To verify the mathematical model of the panel, an experiment is conducted. The panel is mounted on a shaker and base sine excitation is applied.

From the acceleration responses measured at various locations the modes are identified. The first two modes are predicted as Hz and by: 3. Karen H. Lyle's research while affiliated with Hampton VA Medical Center and Predicted and Measured Strain Responses of Isotropic Panels to Base Excitation.

panels excited through the base. Simple analytical formulae are derived for the nonlinear strain response of composite plates to broadband acoustic excitation.

The beam mode shape functions with the same boundary conditions as the plate are used. The effects of flexibility and coupling of Cited by: 2. The behavior of six reduced-scale reinforced soil walls under base excitation is investigated using physical shaking table tests.

The models were tested to isolate the influence of facing geometry, facing mass and facing toe condition on response to simulated seismic by:   However, in developing tissue-engineered grafts for myocardial repair, it has become apparent that previous three-dimensional (3D) scaffold materials are structurally and mechanically incompatible with the formation of a fully biomimetic tissue.

Isotropic collagen foams and gels yield isolated regions of cardiomyocyte alignment, Cited by: The transmission of sound through simple infinite isotropic panels can be predicted in a straightforward manner using well-established analytical models.

Frequency response analysis is an efficient method for finding the steady-state response to sinusoidal excitation. In frequency response analysis, the loading is a sine wave for which the frequency, amplitude, and phase are specified.

Frequency response analysis is limited to linear elastic structures. Physical Modeling and Response of Sand Deposits Subjected to Biaxial Base Excitation. El Shafee.

1, T. Abdoun. and M. Zeghal. ABSTRACT. The effects of arthquake e loading on site response are complex and three dimensional. A series of centrifuge tests were conducted to assess the response and liquefaction 3D a level site of deposit.

In the second method, strain–stress curves are determined by mechanical stretching, and the strain S 31 is measured by comparing the strains obtained with and without an electric field. The two methods lead to similar M 31 * coefficients that are close to 10 −18 m 2 V −2.

The review presents developments concerning the modelling of vibration control systems with hysteresis. In particular, the review focuses on applications of the Bouc-Wen model that describes accurate hysteretic behaviour in vibration control devices.

The review consists of theoretical aspects of the Bouc-Wen model, identification procedures, and applications in vibration by: 5. The shear modulus is one of several quantities for measuring the stiffness of materials. All of them arise in the generalized Hooke's law: Young's modulus E describes the material's strain response to uniaxial stress in the direction of this stress (like pulling on the ends of a wire or putting a weight on top of a column, Derivations from other quantities: G = τ / γ, G = E.

Qualitative and Quantitative Assessment of Isotropic Ankle Magnetic Resonance Imaging: Three-Dimensional Isotropic Intermediate-Weighted Turbo Spin Echo versus Three-Dimensional Isotropic Fast Field Echo Sequences Hyun Su Kim, MD1, Young Cheol Yoon, MD1, Jong Won Kwon, MD1, Bong-Keun Choe, MD, PhD2.

At the strain level of interest, we immobilize the specimen by fixing the slide block on the slide guide and measure the displacement in a Cited by: In order to show the effect of magnetic field on the dynamic behavior of MREs, we measured the stress–strain response of MREs to harmonic oscillation at constant frequency and strain for different levels of applied magnetic flux density, from B = 0 mT to B = mT (shown in figure 7).

By increasing magnetic flux density, for the same strain. LECTURE NOTES 6 ELECTROMAGNETIC WAVES IN MATTER Electromagnetic Wave Propagation in Linear Media We now consider EM wave propagation inside linear matter, but only in regions where there are NO free charges free 0 and/or free currents Kfree 0 (i.e.

the linear medium is an insulator / a non-conductor).File Size: KB. The responses of cantilevered and clamped-free-clamped-free (C-F-C-F) rectangular, isotropic panels subjected to base excitation applied at the clamped ends were experimentally determined in this investigation.

A photograph showing the apparatus used to study panel response for cantilevered panels is shown in figure 1. The model was then validated by comparing predicted contact stresses with measured stresses from the actual radial truck tire.

Contact stress analysis was conducted to evaluate tire responses under different levels of normal load and inflation pressure. Excellent correspondence between predicted and measured contact stresses was observed.

Imaging with the 3D TSE intermediate-weighted sequence with refocusing control (volume isotropic turbo spin echo acquisition [VISTA]) and the 3D isotropic FFE sequence (water-selective sequence, fluid [WATS-f]; non-spoiled FFE 3D volume scan with the principle of selective excitation technique [ProSet]) was performed.

Applications Edit. Raman spectroscopy is used in chemistry to identify molecules and study chemical bonding and intramolecular bonds. Because vibrational frequencies are specific to a molecule's chemical bonds and symmetry (the fingerprint region of organic molecules is in the wavenumber range – cm −1).

The strain is produced by a system of forces; the force acting on unit area is known as the stress. The basic principles of elasticity can be found in most textbooks on materials science (e.g.). In summary: For a homogeneous isotropic solid, the ratio of stress/strain is a constant, called the modulus of by: Mechanics of Structures and Materials: Advancements and Challenges is a collection of peer-reviewed papers presented at the 24th Australasian Conference on the Mechanics of Structures and Materials (ACMSM24, Curtin University, Perth, Western Australia, December ).

The contributions from aca. The phase equilibrium evolution resulting from the interdiffusion of atoms in single crystals of nickel-based superalloys was studied with the aid of microstructural, chemical composition, and micromechanical property investigations.

The experimental observation methods—optical microscopy, scanning electron microscopy, transmission electron microscopy, energy Cited by: 1. A Strain gauge is a sensor whose resistance varies with applied force; It converts force, pressure, tension, weight, etc., into a change in electrical resistance which can then be measured.

When external forces are applied to a stationary object, stress and strain are the result. Stress is defined as the object's internal resisting forces, and. Stress Strain Curve. Proportional limit is the point on a stress-strain curve at which it begins to deviate from the straight-line relationship between stress and strain.

See accompanying figure at (1 & 2). Elastic limit is the maximum stress to which a specimen may be subjected and still return to its original length upon release of the load. Stress in a Finite, Fixed-Free Rod, Longitudinal Response Excited by Resonant Base Excitation Consider a fixed-free rod subjected to base excitation.

Equation (2) applies as long as the excitation is sinusoidal with a frequency equal to the natural frequency of the corresponding mode.

The derivation is given in Appendix C. The laser-displacement-sensor was fixed at the free end of pipe and the strain-gauge was adhesive at the root of the pipe. The first frequency of specimen was measured by these sensors. The first resonance frequency fell rapidly with the increment of the excitation loads of the shaker.

Thermomechanical Response of Shape Memory Alloy Hybrid Composites by Travis L. Turner Excellent agreement is achieved between the predicted and measured responses including thermal buckling, thermal post-buckling, and dynamic response due to inertial loading.

1 1E measure Where E2 is the actual strain matrix and E2 measure is the matrix of measured 12 [12 measure Tool strains. Et ot is the deformation of the autoclave tool when it was cooled down from 0 curing temperature to room temperature. The thermal chamber (Figure ) was used to determine the tool deformation at the curing temperature of.

Piezoelectricity is the electric charge that accumulates in certain solid materials (such as crystals, certain ceramics, and biological matter such as bone, DNA and various proteins) in response to applied mechanical word piezoelectricity means electricity resulting from pressure and latent heat.

It is derived from the Greek word πιέζειν; piezein, which means to squeeze or. Contact pressure, tangential stress, shear stress, equivalent plastic strain, tangential plastic strain and also shear plastic strain are gathered and analysed. It is found that the plastic strain response of the combined isotropic-kinematic hardening plasticity model is slightly higher compare to linear kinematic hardening plasticity model [1].

Structural Health Monitoring From System Integration to Autonomous Systems. Editor: Fu-Kuo Chang, Department of Aeronautics and Astronautics, Stanford University. Proceedings of the Seventh International Workshop on Structural Health Monitoring, SeptemberA key aspect of this work was to measure accurate stress-strain hysteresis loops at shearing strains be­ low percent.

To accomplish this task, the motion monitoring system in the torsional shear test was modified with a micro-proximitor system, and shear modulus was measured at strains as small as File Size: 6MB. material constants μi, αi in the strain-energy function ⎟⎟ ⎟ ⎠ ⎞ ⎜⎜ ⎜ ⎝ ⎛ −+ −+ ∑ = ∑ = = ≡ i 1 cα λ i 1 α i λ μ M i 1,c) i P(λ(α i μ M i 1 F (0) for incompressible isotropic elastic materials.

In equation (0), F represents the force per unit undeformed area corresponding to .Read chapter 3 Hydrodynamics in Ship Design: The Twenty-Second Symposium on Naval Hydrodynamics was held in Washington, D.C., from AugustIt c.These panels have been subjected to physical testing to measure density, fiber volume fraction, and void fraction.

Coupons machined from these panels have also been subjected to mechanical testing to measure elastic properties and strength of the laminates using tensile, compressive, transverse tensile, and in-plane shear tests.