DYNAMIC RESPONSE OF TIMBER BRIDGES AS A TOOL TO MEASURE STRUCTURAL INTEGRITY

2003 ◽  
Vol 27 (3) ◽  
pp. 25-28
Author(s):  
A.M. Morison ◽  
C.D. Karsen ◽  
H.A. Evensen ◽  
J.B. Ligon
Keyword(s):  
Dynamic Response ◽  
Structural Integrity ◽  
Timber Bridges

Dynamic Response Analysis of Control Rod Drive Mechanism Under the Stepping Impact Force for Nuclear Power Plants

2012 ◽  
Author(s):  
Xiaoyao Shen ◽  
Yongcheng Xie
Keyword(s):  
Dynamic Response ◽  
Nuclear Power ◽  
Power Plants ◽  
Structural Integrity ◽  
Impact Force ◽  
Response Analysis ◽  
Control Rod ◽  
Drive Mechanism ◽  
Finite Element Software ◽  
The Impact

The control rod drive mechanism (CRDM) is an important safety-related component in the nuclear power plant (NPP). When CRDM steps upward or downward, the pressure-containing housing of CRDM is shocked axially by an impact force from the engagement of the magnetic pole and the armature. To ensure the structural integrity of the primary coolant loop and the functionality of CRDM, dynamic response of CRDM under the impact force should be studied. In this manuscript, the commercial finite element software ANSYS is chosen to analyze the nonlinear impact problem. A nonlinear model is setup in ANSYS, including main CRDM parts such as the control rod, poles and armatures, as well as nonlinear gaps. The transient analysis method is adopted to calculate CRDM dynamic response when it steps upward. The impact loads and displacements at typical CRDM locations are successfully obtained, which are essential for design and stress analysis of CRDM.

Evaluation of the structural integrity of timber bridges

1999 ◽  
Vol 32 (1) ◽  
pp. 43-48 ◽  
Author(s):  
M.L Peterson ◽  
R.M Gutkowski
Keyword(s):  
Structural Integrity ◽  
Timber Bridges

scholarly journals THEORETICAL ANALYSIS OF DYNAMIC RESPONSE OF A BRIDGE SECTION LOADING BY THE IMPULSIVE FORCE

2017 ◽  
Vol 18 (2) ◽  
Author(s):  
ADRIAN LEOPA
Keyword(s):  
Dynamic Response ◽  
Seismic Design ◽  
Mathematical Theory ◽  
Structural Integrity ◽  
Road Traffic ◽  
Physical Models ◽  
General Nature ◽  
Impulsive Force ◽  
Dynamic Insulation ◽  
Bridge Structures

<p>The work in seismic design of bridges is needed to develop physical models and mathematical theory, based on which will be assessed and quantified the dynamic response of bridge structures subjected to stress arising from road traffic or seismic activity.</p><p>The need for this modeling is imposed three requirements: to ensure the structural integrity of the bridge elements for subjected impulsive, proper choice of dynamic insulation elements placed as a interface between the superstructure and infrastructure, as well as analysis of effects on joints in these situations demand. This paper proposes a physical model of a general nature, enabling customization depending on the specific constructive bridge, or the way it is solicited. Customize this model was developed for this study based on the existing viaduct Transylvania highway located between km 29 +602.75 and km 29 +801.25.</p>

Structural Health Monitoring Using Modal Strain Energy

1995 ◽  
Author(s):  
Robert S. Ballinger ◽  
David W. Herrin
Keyword(s):  
Dynamic Response ◽  
Modal Analysis ◽  
Strain Energy ◽  
Structural Integrity ◽  
Dynamic Structure ◽  
Experimental Modal Analysis ◽  
Modal Strain Energy ◽  
Various Boundary Conditions ◽  
Structural Region ◽  
High Strain Energy

Abstract This research combines analytical and experimental modal analysis techniques to verify the structural integrity or monitor the “health” of a dynamic structure. Central to the procedure is the development of a baseline dynamic fingerprint model of the structure. The dynamic fingerprint is verified with experimental modal analysis and correlation. After the structure is placed into service, damage can be determined by comparing the current dynamic response with the baseline dynamic fingerprint response. The unique aspect of this procedure is that the current dynamic response is enforced on the undamaged baseline dynamic fingerprint model. Should damage exist, the structure is forced to deform in an unnatural manner, and high strain energy results. Significant differences in the normalized modal or operating strain energy density identify structural regions where a loss of stiffness, weakening of the structure, and/or damage has occurred. This identification of a potentially “unhealthy” structural region allows a quick visual inspection of the region or further analytical and/or experimental submodelling of the area to precisely identify the damage. The method is ideally suited to CAE application. The method is demonstrated analytically and experimentally for two structures: an eight-bay cantilevered truss structure and a rectangular plate with various boundary conditions.

Mechanical Properties of Wood and Timber Bridge Evaluation

2014 ◽  
Vol 587-589 ◽  
pp. 1381-1385
Author(s):  
Ling Ling Yu ◽  
Jie Jun Wang ◽  
Te Huang
Keyword(s):  
Mechanical Properties ◽  
Structural Integrity ◽  
Strength Properties ◽  
Structural Elements ◽  
Bridge Evaluation ◽  
Bridge Structures ◽  
And Performance ◽  
Inspection Techniques ◽  
Non Destructive ◽  
Timber Bridges

Wood possesses material properties that may be significantly different from other materials normally encountered in structural design. It is necessary for the engineer to have a general understanding of the properties and characteristics that affect the strength and performance of wood in bridge applications. This paper discusses the mechanical properties of wood, including elastics properties and strength properties. Timber bridge are often exposed to harsh environment conditions. Over time, this exposure can lead to deterioration. In turn, this deterioration may lead to a loss of structural integrity that is detrimental to the structure and its users. Timber structural elements are susceptible to degradation due to environmental and loading conditions. A variety of inspection techniques can be employed to locate damage and decay in timber members in order to maintain structural performance. Methods of non-destructive techniques for timber bridges are getting more and more important. This paper presents several non-destructive methods to timber bridge structures.

Holographic Interferometry in Automotive Powertrain Component Engineering Analysis

1995 ◽  
Author(s):  
James W. Forbes ◽  
Mitchell M. Marchi ◽  
Alexander Petniunas ◽  
Raymond R. Wales
Keyword(s):  
Dynamic Response ◽  
Holographic Interferometry ◽  
Structural Integrity ◽  
Engineering Analysis ◽  
Design Requirement ◽  
Noise And Vibration ◽  
Vehicle System ◽  
System Components ◽  
Automotive Powertrain ◽  
System Requirements

Abstract As increased performance and vehicle system requirements are placed on automotive powertrains more sophisticated methods of engineering analysis are required in their development. Since the containment of noise and vibration is a major design requirement for powertrains, experimental techniques such as laser holographic interferometry are used to tune the dynamic response of system components. This allows the overall system to be optimized from a noise and vibration standpoint as well as from the standpoint of structural integrity. This paper will discuss a variety of examples of how powertrain components have been optimized with the use of holographic methodology.

Electron Beam Damage of Biomolecules Assessed by Energy Loss Spectroscopy

1978 ◽  
Vol 36 (3) ◽  
pp. 61-69
Author(s):  
M. Isaacson ◽  
M.L. Collins ◽  
M. Listvan
Keyword(s):  
Electron Microscopy ◽  
Radiation Damage ◽  
Structural Integrity ◽  
Analytical Electron Microscopy ◽  
High Dose ◽  
Dose Rates ◽  
Special Cases ◽  
Analytical Electron ◽  
Atom Migration ◽  
Beam Damage

Over the past five years it has become evident that radiation damage provides the fundamental limit to the study of blomolecular structure by electron microscopy. In some special cases structural determinations at very low doses can be achieved through superposition techniques to study periodic (Unwin & Henderson, 1975) and nonperiodic (Saxton & Frank, 1977) specimens. In addition, protection methods such as glucose embedding (Unwin & Henderson, 1975) and maintenance of specimen hydration at low temperatures (Taylor & Glaeser, 1976) have also shown promise. Despite these successes, the basic nature of radiation damage in the electron microscope is far from clear. In general we cannot predict exactly how different structures will behave during electron Irradiation at high dose rates. Moreover, with the rapid rise of analytical electron microscopy over the last few years, nvicroscopists are becoming concerned with questions of compositional as well as structural integrity. It is important to measure changes in elemental composition arising from atom migration in or loss from the specimen as a result of electron bombardment.

Structural integrity after cold storage of human epidermal model in hypothermosol: A correlative ultrastructural and fluorescent assay

1994 ◽  
Vol 52 ◽  
pp. 270-271
Author(s):  
Henry H. Eichelberger ◽  
John G. Baust ◽  
Robert G. Van Buskirk
Keyword(s):  
Cold Storage ◽  
Structural Integrity ◽  
Culture Media ◽  
Cell Structure ◽  
Natural State ◽  
Sodium Cacodylate ◽  
Ruthenium Tetroxide ◽  
Cacodylate Buffer ◽  
Before And After

For research in cell differentiation and in vitro toxicology it is essential to provide a natural state of cell structure as a benchmark for interpreting results. Hypothermosol (Cryomedical Sciences, Rockville, MD) has proven useful in insuring the viability of synthetic human epidermis during cold-storage and in maintaining the epidermis’ ability to continue to differentiate following warming.Human epidermal equivalent, EpiDerm (MatTek Corporation, Ashland, MA) consisting of fully differentiated stratified human epidermal cells were grown on a microporous membrane. EpiDerm samples were fixed before and after cold-storage (4°C) for 5 days in Hypothermosol or skin culture media (MatTek Corporation) and allowed to recover for 7 days at 37°C. EpiDerm samples were fixed 1 hour in 2.5% glutaraldehyde in sodium cacodylate buffer (pH 7.2). A secondary fixation with 0.2% ruthenium tetroxide (Polysciences, Inc., Warrington, PA) in sodium cacodylate was carried out for 3 hours at 4°C. Other samples were similarly fixed, but with 1% Osmium tetroxide in place of ruthenium tetroxide. Samples were dehydrated through a graded acetone series, infiltrated with Spurrs resin (Polysciences Inc.) and polymerized at 70°C.

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