Structural and Dynamic Behavior of Pretwisted Rods and Beams

1991 ◽  
Vol 44 (12) ◽  
pp. 483-515 ◽  
Author(s):  
Aviv Rosen
Keyword(s):  
Composite Materials ◽  
Dynamic Analysis ◽  
Dynamic Behavior ◽  
Static Analysis ◽  
High Temperatures ◽  
The Other ◽  
Present Review ◽  
Structural Elements ◽  
Coupling Effects ◽  
Very High

Because of being important structural elements in many engineering applications on one hand, and presenting inherent complicated coupling effects on the other hand, pretwisted rods have attracted the interest of many researchers. During the years, as a result of engineering breakthroughs, like the introduction of composite materials or operating at very high temperatures, the problems associated with pretwisted rods became more complicated. The present review will present the research during the last fifty years. It will be divided into three main subjects: static analysis, dynamic analysis and stability problems. The review will concentrate on the structural and dynamic aspects of pretwisted rods. Derivations of models and solution techniques will be addressed.

Dynamic analysis of swivel construction method under multi-variable coupling effects

2019 ◽  
Vol 10 (4) ◽  
pp. 580-598
Author(s):  
Wang Jiawei ◽  
Sun Quansheng
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Model ◽  
Static Analysis ◽  
Friction Stress ◽  
Construction Method ◽  
Coupling Effects ◽  
Content Type ◽  
Multiple Factors ◽  
Real State ◽  
Variable Coupling

Purpose Swivel construction is a new bridge construction method, which can minimize the impact on railway and highway traffic. Previous studies were based on single factor and static analysis, which cannot reflect the real state of structures. The purpose of this paper is to establish a dynamic model of the structure and to analyze the situation under multi-variable coupling effects to accurately simulate the real state of the structure. Design/methodology/approach Finite element software ANSYS was used to establish dynamic model of turntable structure and then to analyze the effects of multiple factors on total stress, friction stress and slipping distance of the turntable structure. Findings It is concluded that the unbalanced weight and radius of spherical hinges have great influence on the turntable structure, so the design should be strictly considered. Friction stress and angular acceleration have little effect on the turntable structure. Originality/value This paper provides simulation of the whole process of swivel construction method. Whereas previous studies focused on static analysis, this paper focuses on the dynamic analysis of swivel construction method. The mechanics of the swivel structure under multiple factors was analyzed. According to the analysis results, the design parameters of the turntable structure are optimized.

On Application of Theory of Distributions to Static and Dynamic Analysis of Cracked Beams

2016 ◽  
Vol 16 (10) ◽  
pp. 1550073 ◽  
Author(s):  
Ricardo Oscar Grossi ◽  
Javier Leandro Raffo
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Behavior ◽  
Numerical Results ◽  
Structural Elements ◽  
Computationally Efficient ◽  
Static And Dynamic Analysis ◽  
Rigorous Framework ◽  
Rigorous Study ◽  
Vibration Problems ◽  
Derivatives Of

This paper presents a rigorous study on the static and dynamic behavior of beams affected by cracks. The theory of distributions developed by Laurent Schwartz is adopted as it is particularly suitable for the treatment of discontinuities in functions for the deflection and derivatives of the beam. Thus, this paper presents a contribution towards the understanding and application of the theory of distributions to the static and dynamic behavior of structural elements affected by cracks. A simple, computationally efficient and accurate algorithm is developed for the problems of concern. Numerical results are presented for beams with two cracks. The algorithms developed for beams with discontinuities are obtained in a rigorous framework for static and vibration problems.

scholarly journals Polysulfone Composite Membranes with Carbonaceous Structure. Synthesis and Applications

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 609
Author(s):  
Andreea Madalina Pandele ◽  
Oana Steluta Serbanescu ◽  
Stefan Ioan Voicu
Keyword(s):  
Carbon Nanotubes ◽  
Composite Materials ◽  
Carbon Fiber ◽  
Synthesis Method ◽  
Composite Membranes ◽  
Polymeric Membranes ◽  
The Other ◽  
Present Review ◽  
Structure Synthesis ◽  
Wide Range

The present review deals with the latest progress in the field of polysulfone composite membranes with carbon nanotubes, carbon fiber and graphene from both perspectives-synthesis and applications. These two fillers, extensively used in the last few years due to their remarkable properties, induce a high value character to the composite materials. On the other hand, polysulfone is one the most used polymers for preparing polymeric membranes due to its high versatility in a wide range of solvents and also to the properties of this remarkable polymer. All types of synthesis method were presented and also a large number of applications from industrial to biomedical were presented and discussed.

scholarly journals Development and study of mechanical behaviour reinforcing composites by waste BTP

2018 ◽  
Vol 149 ◽  
pp. 02012
Author(s):  
M.El kanzaoui ◽  
A. Hajjaji ◽  
A. Guenbour ◽  
R. Boussen
Keyword(s):  
Composite Materials ◽  
Mechanical Response ◽  
Industrial Applications ◽  
Waste Materials ◽  
Structural Elements ◽  
Ceramic Filler ◽  
Metal Structures ◽  
Stiffness Properties ◽  
Strength And Stiffness ◽  
Very High

Composite materials are used in many industrial applications for their excellent mechanical and electric properties and their low density compared to metal structures. Most countries are extremely rich waste materials such as white ceramic breakages which represents a potential to be developed. Ceramic breakages have exceptional properties and could be effectively exploited in the manufacture of composite materials for a wide variety of applications. The composite materials reinforced by construction waste materials, such as ceramic breaks which offer significant benefits and gains in strength and stiffness properties (Young's modulus E : a material whose modulus Young is very high is said rigid).This article covers the benefits of breakages as ceramic filler used for reinforcement in composites, as well as improve the mechanical response of these structural elements (test compression).

High Resolution Electron Microscopy In Situ Observation of Dynamic Behavior of Grain Boundaries and Interfaces at Very High Temperatures

1997 ◽  
Vol 3 (5) ◽  
pp. 393-408 ◽  
Author(s):  
T. Kamino ◽  
K. Sasaki ◽  
H. Saka
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Grain Boundaries ◽  
Dynamic Behavior ◽  
High Temperatures ◽  
High Resolution Electron Microscopy ◽  
In Situ Observation ◽  
Resolution Electron ◽  
Very High

High Resolution Electron Microscopy In Situ Observation of Dynamic Behavior of Grain Boundaries and Interfaces at Very High Temperatures

scholarly journals The emission of electricity from carbon at high temperatures

1912 ◽  
Vol 86 (588) ◽  
pp. 379-396 ◽  
Keyword(s):  
Electrical Properties ◽  
High Temperatures ◽  
Outer Surface ◽  
Atmospheric Pressure ◽  
The Other ◽  
General Study ◽  
Carbon Tube ◽  
Furnace Gases ◽  
Inner Surface ◽  
Very High

This paper is a first communication of the results of some experiments conducted in electric furnaces at atmospheric pressure, and mostly at very high temperatures. The investigation came about originally in an attempt to explain some contamination phenomena which were encountered when short tubes of extremely refractory rare earths were baked in various types of carbon-tube resistance furnaces at temperatures from 1500°C. upwards. An examination of the refractory tubes after baking showed that, in certain circumstances, the outer surface of each tube, instead of having the white and hard appearance of the rest, was carburised and crumbly. The action was not merely a surface one, but extended to an appreciable depth. On the other hand, the inner surface of the tube was comparatively unaffected, although it was freely open to the furnace gases, nor did the blackening occur if the tube was shielded. An explanation which at once suggests itself is that the blackening was produced by particels—possibly electrified—shot off from the carbon walls of the furnace with sufficient velocity to penetrate the material of the refractory tubes some millimetres (4 to 7) away. The circumstances pointed to the desirability of a general study of the electrical properties of the atmospheres of such furnaces.

scholarly journals Stealthy Opaque Predicates in Hardware - Obfuscating Constant Expressions at Negligible Overhead

2018 ◽  
pp. 277-297 ◽  
Author(s):  
Max Hoffmann ◽  
Christof Paar
Keyword(s):  
Intellectual Property ◽  
Dynamic Analysis ◽  
Dynamic Behavior ◽  
Static Analysis ◽  
Building Block ◽  
Hardware Trojans ◽  
Reverse Engineer ◽  
Novel Technique ◽  
Fundamental Building Block ◽  
Cryptographic Hardware

Opaque predicates are a well-established fundamental building block for software obfuscation. Simplified, an opaque predicate implements an expression that provides constant Boolean output, but appears to have dynamic behavior for static analysis. Even though there has been extensive research regarding opaque predicates in software, techniques for opaque predicates in hardware are barely explored. In this work, we propose a novel technique to instantiate opaque predicates in hardware, such that they (1) are resource-efficient, and (2) are challenging to reverse engineer even with dynamic analysis capabilities. We demonstrate the applicability of opaque predicates in hardware for both, protection of intellectual property and obfuscation of cryptographic hardware Trojans. Our results show that we are able to implement stealthy opaque predicates in hardware with minimal overhead in area and no impact on latency.

Structure Analysis Loaded by Interior Blast Effect

2014 ◽  
Vol 617 ◽  
pp. 86-91
Author(s):  
Daniel Makovička ◽  
Daniel Makovička
Keyword(s):  
Stress State ◽  
Dynamic Response ◽  
Dynamic Analysis ◽  
Static Analysis ◽  
Structure Analysis ◽  
Detailed Calculation ◽  
Building Structure ◽  
Structural Elements ◽  
Blast Effect ◽  
Limit Stress

The paper determines the parameters of the explosion wave excited by a terrorist charge and assumption of the building structure of a railway station based on dynamic analysis. Certain simplified methods according to various publications, according to our own experimental results and according to 3D computations based on detailed calculation modelling of the interior of the room are compared to determine the explosive effects. Equivalent static analysis was applied to the dynamic response of the structural elements of the selected room. The damage caused to these structural elements is weighted on the basis of the angle of failure of the central axis / surface, and on the basis of the limit stress state of these structures.

Thrombotic Thrombocytopenic Purpura: Mechanism for Effectiveness of Plasmapheresis

1979 ◽  
Author(s):  
J. G. Kelton ◽  
P. B. Neame ◽  
I. Walker ◽  
A. G. Turpie ◽  
J. McBride ◽  
...  
Keyword(s):  
Platelet Count ◽  
Thrombotic Thrombocytopenic Purpura ◽  
The Other ◽  
Unknown Etiology ◽  
Normal Range ◽  
Antiplatelet Antibody ◽  
Thrombocytopenic Purpura ◽  
Serious Illness ◽  
Normal Platelet ◽  
Very High

Thrombotic thrombocytopenic purpura (TTP) is a rare but serious illness of unknown etiology. Treatment by plasmapheresis has been reported to be effective but the mechanism for benefit is unknown. We have investigated the effect of plasmapheresis in 2 patients with TTP by quantitating platelet associated IgG (PAIgG) levels prior to and following plasmapheresis. Both patients had very high levels of PAIgG at presentation (90 and A8 fg IgG/platelet respectively, normal 0-5). in both, the PAIgG levels progressively fell to within the normal range and the platelet count rose following plasmapheresis. One patient remained in remission with normal platelet counts and PAIgG levels. The other relapsed after plasmapheresis and the PAIgG level rose prior to the fall in platelet count. Plasmapheresis was repeated and resulted in normalization of both the platelet count and PAIgG level. It is suggested that plasmapheresis removes antiplatelet antibody or immune complexes which may be of etiological importance in this illness.

Hybrid polymer composite materials. Part 2. Preparation technology

2020 ◽  
pp. 8-13
Keyword(s):  
Composite Materials ◽  
Impact Toughness ◽  
Polymer Composites ◽  
The Other ◽  
Polymer Materials ◽  
Hybrid Polymer ◽  
Preparation Technology ◽  
Advantages And Disadvantages ◽  
Hybrid Polymer Composite ◽  
The One

The main methods (pressing and winding) of the processing of hybrid polymer composites to obtain items were examined. Advantages and disadvantages of the methods were noted. Good combinations of different-module fibers (carbon, glass, boron, organic) in hybrid polymer materials are described, which allow one to prepare materials with high compression strength on the one hand, and to increase fracture energy of samples and impact toughness on the other hand.

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