Dynamic Behaviour of Structural Elements Liable to Buckling

1986 ◽  
pp. 103-111
Author(s):  
M. A. Souza
Keyword(s):  
Dynamic Behaviour ◽  
Structural Elements

Vibration Modelling of String-Harnessed Beam Structures Using Homogenization Techniques

2014 ◽  
Author(s):  
Blake Martin ◽  
Armaghan Salehian
Keyword(s):  
Continuum Model ◽  
Dynamic Behaviour ◽  
Natural Frequencies ◽  
Strain Tensor ◽  
Space Structures ◽  
Power Cables ◽  
Structural Elements ◽  
Equivalent Continuum Model ◽  
Lagrange Strain ◽  
Equivalent Continuum

Harnessing structural elements with strings, power cables, and signal cables increases the complexity in modelling the dynamic behaviour of such structures. Developing models capable of accurately predicting the dynamic behaviour of these systems is of great importance for space structures that cannot be tested prior to launch. The focus of this work is obtaining an equivalent continuum model for string-harnessed beam-like structures with periodic wrapping patterns. The tension in the string is assumed to vary as the beam deflects. The displacement field with second-order terms is determined and from which the Green-Lagrange strain tensor is obtained. After finding kinetic and potential energy expressions Hamilton’s principle is used to obtain the partial differential equation and boundary conditions. Numerical results for the shift in the natural frequencies are presented for various string properties to investigate their effects on the structure.

On the dynamic behaviour of structural elements carrying elastically mounted, concentrated masses

1977 ◽  
Vol 10 (2) ◽  
pp. 121-145 ◽  
Author(s):  
P.A.A. Laura ◽  
E.A. Susemihl ◽  
J.L. Pombo ◽  
L.E. Luisoni ◽  
R. Gelos
Keyword(s):  
Dynamic Behaviour ◽  
Structural Elements ◽  
Concentrated Masses

Control of Properties of Composite Structures with the Use of Multi-Functional Materials

2008 ◽  
Vol 56 ◽  
pp. 324-333
Author(s):  
Wiesław M. Ostachowicz ◽  
Arkadiusz Zak ◽  
Pawel Malinowski ◽  
Tomasz Wandowski
Keyword(s):  
Composite Structures ◽  
Thermal Activation ◽  
Dynamic Behaviour ◽  
Laminated Composite ◽  
Functional Materials ◽  
Piezoelectric Transducers ◽  
Structural Elements ◽  
Signal Processing Algorithm ◽  
Signal Sources ◽  
Laminated Composite Beams

This work is focused on two major applications of multi–functional materials. In the first one the use of piezoelectric transducers have been studied in order to monitor the health of composite plate–like structures. These transducers can act as signal sources and sensors for guided elastic waves in inspected structures. The excited waves propagating in the material can reflect from various discontinuities such like: boundaries, notches, cracks and delamination. In the next step the time responses registered by the sensors, as inputs for a signal processing algorithm, may be processed to correlate the measured arriving waves with the discontinuities in the structures enabling one to indicate the location of the discontinuities. In the second application the use of shape memory alloy (SMA) components integrated with composite structural elements are investigated. SMA elements in the forms of wires, strips, ribbons, beams, tubes, etc. can be bonded to, or integrated within, various structural elements in order to control their mechanical properties, static as well as dynamic behaviour. This can be obtained thanks to unique effects associated with thermal activation of SMAs leading to significant changes in SMA material properties, which next can also be applied for control purposes. The use of such controllable properties of SMA components in active control of static (deflection) and dynamic (natural frequencies, modes of vibrations, amplitudes of forced vibrations) characteristics of laminated composite beams–like structures have been demonstrated.

Structural phenomena in the growth of carbon nanotubes

1993 ◽  
Vol 51 ◽  
pp. 750-751
Author(s):  
Jun Jiao
Keyword(s):  
Carbon Nanotubes ◽  
Growth Mechanism ◽  
Carbonaceous Material ◽  
Cluster Growth ◽  
Structural Elements ◽  
Rich Variety ◽  
Different Shapes ◽  
Point To Point

HREM studies of the carbonaceous material deposited on the cathode of a Huffman-Krätschmer arc reactor have shown a rich variety of multiple-walled nano-clusters of different shapes and forms. The preparation of the samples, as well as the variety of cluster shapes, including triangular, rhombohedral and pentagonal projections, are described elsewhere.The close registry imposed on the nanotubes, focuses attention on the cluster growth mechanism. The strict parallelism in the graphitic separation of the tube walls is maintained through changes of form and size, often leading to 180° turns, and accommodating neighboring clusters and defects. Iijima et. al. have proposed a growth scheme in terms of pentagonal and heptagonal defects and their combinations in a hexagonal graphitic matrix, the first bending the surface inward, and the second outward. We report here HREM observations that support Iijima’s suggestions, and add some new features that refine the interpretation of the growth mechanism. The structural elements of our observations are briefly summarized in the following four micrographs, taken in a Hitachi H-8100 TEM operating at an accelerating voltage of 200 kV and with a point-to-point resolution of 0.20 nm.

Designing TIMP (tissue inhibitor of metalloproteinases) variants that are selective metalloproteinase inhibitors

2003 ◽  
Vol 70 ◽  
pp. 201-212 ◽  
Author(s):  
Hideaki Nagase ◽  
Keith Brew
Keyword(s):  
Three Dimensional ◽  
Therapeutic Interventions ◽  
Tissue Inhibitors Of Metalloproteinases ◽  
Structural Basis ◽  
Structural Elements ◽  
Ridge Structure ◽  
Extracellular Matrix Components ◽  
Metalloproteinase Inhibitors ◽  
The Matrix ◽  
A Disintegrin And Metalloproteinase

The tissue inhibitors of metalloproteinases (TIMPs) are endogenous inhibitors of the matrix metalloproteinases (MMPs), enzymes that play central roles in the degradation of extracellular matrix components. The balance between MMPs and TIMPs is important in the maintenance of tissues, and its disruption affects tissue homoeostasis. Four related TIMPs (TIMP-1 to TIMP-4) can each form a complex with MMPs in a 1:1 stoichiometry with high affinity, but their inhibitory activities towards different MMPs are not particularly selective. The three-dimensional structures of TIMP-MMP complexes reveal that TIMPs have an extended ridge structure that slots into the active site of MMPs. Mutation of three separate residues in the ridge, at positions 2, 4 and 68 in the amino acid sequence of the N-terminal inhibitory domain of TIMP-1 (N-TIMP-1), separately and in combination has produced N-TIMP-1 variants with higher binding affinity and specificity for individual MMPs. TIMP-3 is unique in that it inhibits not only MMPs, but also several ADAM (a disintegrin and metalloproteinase) and ADAMTS (ADAM with thrombospondin motifs) metalloproteinases. Inhibition of the latter groups of metalloproteinases, as exemplified with ADAMTS-4 (aggrecanase 1), requires additional structural elements in TIMP-3 that have not yet been identified. Knowledge of the structural basis of the inhibitory action of TIMPs will facilitate the design of selective TIMP variants for investigating the biological roles of specific MMPs and for developing therapeutic interventions for MMP-associated diseases.

Structural Elements of Social Psychology of Sport--Study on the Research Objects

2011 ◽  
Author(s):  
Su Qingfu ◽  
Sha Shuang ◽  
Feng Di ◽  
Liu Lifeng
Keyword(s):  
Social Psychology ◽  
Structural Elements ◽  
Research Objects

Investigation of fused silica dynamic behaviour

2006 ◽  
Vol 134 ◽  
pp. 929-934 ◽  
Author(s):  
F. Malaise ◽  
J.-M. Chevalier ◽  
I. Bertron ◽  
F. Malka
Keyword(s):  
Dynamic Behaviour ◽  
Fused Silica

A MODEL FOR THE FATIGUE SATURATION RANGE OF ALUMINIUM FROM DYNAMIC BEHAVIOUR AND INTERACTIONS OF DISLOCATIONS

1987 ◽  
Vol 48 (C8) ◽  
pp. C8-155-C8-160
Author(s):  
R. FOUGERES ◽  
J. CHICOIS ◽  
A. HAMEL ◽  
A. VINCENT
Keyword(s):  
Dynamic Behaviour

Analysis of the Multi-Channel Epileptiform EEG Using the Markov Chains Formalism

1989 ◽  
Vol 28 (03) ◽  
pp. 160-167 ◽  
Author(s):  
P. Penczek ◽  
W. Grochulski
Keyword(s):  
Dynamic Behaviour ◽  
Joint Probability ◽  
Drug Effects ◽  
Anticonvulsant Drug ◽  
Channel System ◽  
Markov Network ◽  
Eeg Data ◽  
Multi Level ◽  
Joint Probability Functions ◽  
Dependent State

Abstract:A multi-level scheme of syntactic reduction of the epileptiform EEG data is briefly discussed and the possibilities it opens up in describing the dynamic behaviour of a multi-channel system are indicated. A new algorithm for the inference of a Markov network from finite sets of sample symbol strings is introduced. Formulae for the time-dependent state occupation probabilities, as well as joint probability functions for pairs of channels, are given. An exemplary case of analysis in these terms, taken from an investigation of anticonvulsant drug effects on EEG seizure patterns, is presented.

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