Suppression of Internal Damping-Induced Instability Using Adaptive Techniques

2007 ◽  
Author(s):  
Andra´s Simon ◽  
George Flowers
Keyword(s):  
Composite Materials ◽  
Simulation Modeling ◽  
High Speed ◽  
High Strength ◽  
Light Weight ◽  
Internal Damping ◽  
Modeling And Analysis ◽  
Rotor Systems ◽  
Rotor Spinning ◽  
High Speeds

Advanced rotor systems, for such applications as high-speed flywheel systems, consist (in a basic fashion) of a lightweight rotor spinning at relatively high speeds and supported by magnetic bearings. Composite materials are an extremely attractive choice for such rotor designs, offering high strength with light-weight. However, there are a number of issues that must be addressed for such efforts to be successful. Specific issues include imbalance control and active techniques to suppress internal damping-induced instability. A detailed description of the problem being considered and a strategy for solving it are presented. Simulation modeling and analysis results are presented and discussed to illustrate the method and demonstrate its effectiveness.

The Relation of the Interlaminar Fracture Toughness and the Acoustic Emission (Ae) under the Enf Test

2007 ◽  
Vol 353-358 ◽  
pp. 279-282
Author(s):  
Juho Kwak ◽  
Yu Seong Yun ◽  
Oh Heon Kwon
Keyword(s):  
Fracture Toughness ◽  
Composite Materials ◽  
Laminate Composite ◽  
High Strength ◽  
Light Weight ◽  
Interlaminar Fracture Toughness ◽  
Laminate Composites ◽  
Interlaminar Fracture ◽  
Good Corrosion Resistance ◽  
Enf Test

Recently, composite materials are used in many fields because their properties are high strength, high stiffness, and they have light weight, good corrosion resistance and good thermal conductivity. However, composite materials have relatively a lot of problems, especially delamination, compared with common materials such as a steel and aluminum, etc. Therefore, having the interlaminar fracture toughness for a laminate composite is important. In this study, the end notched flexure (ENF) specimens are employed in order to evaluate modeⅡ interlaminar fracture toughness for CFRP laminate composites. Three kinds of a/L ratio were applied to these specimens under the different pressure level. Also, we discuss the relation of crack growth and the interlaminar fracture toughness in terms of AE characteristics using ENF test.

scholarly journals A nonlinear model for rotor-shaft joints of high speed rotor systems with internal damping

PAMM ◽  
2008 ◽  
Vol 8 (1) ◽  
pp. 10371-10372
Author(s):  
Jonas Fischer ◽  
Jens Strackeljan
Keyword(s):  
Nonlinear Model ◽  
High Speed ◽  
Internal Damping ◽  
Rotor Systems ◽  
Rotor Shaft

Application of New Design Method by High-Strength Composite Material

2014 ◽  
Vol 607 ◽  
pp. 915-919 ◽  
Author(s):  
Haruhiko Iida ◽  
Toshiaki Fujishima ◽  
Yoshifumi Ohbuchi ◽  
Hidetoshi Sakamoto
Keyword(s):  
Composite Materials ◽  
Product Design ◽  
Design Method ◽  
High Strength ◽  
New Product ◽  
Point Of View ◽  
Light Weight ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Separate Product

The purpose of this study is to apply a new design method, which integrates both optimum strength and product design. Here, the collaboration of design and strength by using composite materials is administered. Many products, which are made from high strength composite materials, require new product design technology. Existing product developments tend to separate product design from product planning. The process begins from planning the shape of the product, then calculating the strength, and lastly designing the product. In our new design method, we create from an engineering point of view. By using a design method of high-strength materials, we designed a new ZIGZAG CHAIR made of carbon fiber reinforced plastic of excellent strength and light-weight.

Preliminary Design of Tubular Composite Structures Using Netting Theory and Composite Degradation Factors

1995 ◽  
Vol 117 (4) ◽  
pp. 390-394 ◽  
Author(s):  
B. W. Tew
Keyword(s):  
Corrosion Resistance ◽  
Composite Materials ◽  
Cyclic Loading ◽  
Composite Structures ◽  
High Strength ◽  
Preliminary Design ◽  
Light Weight ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Design Calculations

Tubular products and process vessels built using fiber-reinforced composite materials provide significant advantages in applications that require corrosion resistance, high strength, and light weight. A design approach based on netting theory is presented which enables engineers to develop preliminary structural designs for these structures using composite materials. The integration of creep, cyclic loading, and environmental degradation factors into initial design calculations is also discussed and illustrated.

Bio-Inspired Synthesis of Al2O3/Polymer Composite

2012 ◽  
Vol 724 ◽  
pp. 107-110
Author(s):  
Kyung Mok Nam ◽  
Yoon Joo Lee ◽  
Soo Ryong Kim ◽  
Woo Teck Kwon ◽  
Hyung Sun Kim ◽  
...  
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Bending Strength ◽  
High Strength ◽  
Organic Polymer ◽  
Ceramic Plate ◽  
Light Weight ◽  
Polymeric Compound ◽  
Inorganic Hybrid ◽  
Inorganic Composite

The formation of organic-inorganic hybrid composite with ceramic platelets and polymeric compound can have the higher strength and higher elasticity than metal, which is a nanocomposite with high strength and light weight. Ceramic platelet such as Al2O3has been used to form organic-inorganic composite material using PMMA as an organic polymer. Bending strength and density of the composites prepared by infiltration and post-warm pressing were measured. FE-SEM and TG analysis were carried out to determine the microstructure of the organic-inorganic composite materials. Bending strengths and densities of the composites prepared by Al2O3ceramic plate and PMMA after post-warm pressing were ~70MPa and ranged from 2.4 to 2.6, respectively.

Mass loss and blunting during high-speed penetration

2004 ◽  
Vol 218 (9) ◽  
pp. 1053-1062 ◽  
Author(s):  
R N Davis ◽  
A M Neely ◽  
S E Jones
Keyword(s):  
Mass Loss ◽  
High Speed ◽  
Sliding Friction ◽  
Subsequent Development ◽  
High Strength ◽  
Target Strength ◽  
Velocity Dependence ◽  
High Speeds ◽  
Coefficient Of Sliding Friction ◽  
Penetration Data

A new analytical model of high-speed friction was developed to account for the observed velocity dependence in sliding friction at high speeds and was successfully applied to the analysis of data previously reported by Jones et al. for a number of concrete penetration tests using ogive-nose projectiles of high-strength steel alloy. The model permitted very consistent predictions of penetrator performance and target strength based on the experimental data. The subsequent development by Davis et al. of a stepwise incremental approximation to the velocity-dependent coefficient of sliding friction simplified the implementation of the model, while preserving the quality of the linear approximation to the assumed velocity dependence in sliding friction at high speeds. The stepwise function further led to an engineering model for mass loss, neglecting the effects of blunting, which successfully related the work done by friction to the mass loss due to surface melting of the nose. In this paper, a generalized dimensionless nose equation is developed, allowing these results to be applied to geometries other than the ogival case. Furthermore, the effects of blunting and progressive mass loss from the nose are incorporated into the existing model of high-speed penetration and applied to the analysis of previously reported penetration data. By incorporating changing nose mass and geometry due to frictional wear, the performance characteristics of steel alloys and selected nose geometries can be better evaluated, and the processes governing high-speed penetration and mass loss better understood. Given penetrator material, impact velocity and target properties, it is also possible to predict the performance of various nose geometries.

Investigation of Mechanical Properties of Unidirectional Fibrous Composite by Micro-Mechanics Model

2012 ◽  
Vol 487 ◽  
pp. 481-486
Author(s):  
Kazem Reza-Kashyzadeh ◽  
Shokoofeh Dolati
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Fibrous Composite ◽  
Weight Ratio ◽  
High Strength ◽  
Element Model ◽  
Full Description ◽  
Modeling And Analysis ◽  
Unidirectional Fibrous Composite ◽  
Hardness Coefficient

The use of advanced composite materials reinforced with fibers is expanded in these years. The main reason for the increased use of these materials is their high strength and hardness coefficient, their density and low prices. So, the fiber-reinforced composite materials can be used in the design of structures that require high strength to weight ratio and hardness coefficient. In order to replace these materials and new applications, many research programs to study the mechanical behavior of these materials has shifted. In this paper Finite element model presented in which the fibers and matrix are modeled separately and to show a full description of the properties of the constituent components, the interface between matrix and fiber discontinuity is presented in the model With using modeling and analysis after great determination of mechanical properties of unidirectional fibrous composite single and compared with experimental results, the elastic modulus changes depending on the angle of the fibers is received . The results of this method are compared with available mathematical models.

The Development of a High Elastic 3D Prefabricated Composite

2011 ◽  
Vol 332-334 ◽  
pp. 1773-1776
Author(s):  
Yun Xing Liang ◽  
Li Chen ◽  
Hai Wen Liu ◽  
Hua Wu Liu
Keyword(s):  
Statistical Analysis ◽  
Composite Materials ◽  
High Strength ◽  
Modern Technology ◽  
Light Weight ◽  
Optimal Ratio ◽  
Reinforced Composite ◽  
Fiberglass Composite ◽  
Fiberglass Fabric ◽  
Polyurethane Matrix

With the development of modern technology, fiberglass composite materials are widely applied. The advantages of fiberglass reinforced composite materials are high strength and light weight. In order to produce a prefabricated fiberglass composite, a machine chart was drafted for weaving the 3D fiberglass fabric with five layers. The obtained five-layer 3D fabrics were composited with polyurethane matrix. Afterwards, the performance of the prefabricated composites was tested and the optimal ratio of fiberglass to matrix was determined by statistical analysis.

Microstructure of an extruded rapidly solidified Al-8Fe-2Mo alloy

1986 ◽  
Vol 44 ◽  
pp. 548-549
Author(s):  
W. T. Donlon ◽  
J. E. Allison ◽  
S. Shinozaki
Keyword(s):  
Electron Microscopy ◽  
Automotive Industry ◽  
Fuel Economy ◽  
High Strength ◽  
Al Alloys ◽  
Light Weight ◽  
Thin Sections ◽  
Strength And Durability ◽  
Rapidly Solidified ◽  
Whitney Aircraft

Light weight materials which possess high strength and durability are being utilized by the automotive industry to increase fuel economy. Rapidly solidified (RS) Al alloys are currently being extensively studied for this purpose. In this investigation the microstructure of an extruded Al-8Fe-2Mo alloy, produced by Pratt & Whitney Aircraft, Goverment Products Div. was examined in a JE0L 2000FX AEM. Both electropolished thin sections, and extraction replicas were examined to characterize this material. The consolidation procedure for producing this material included a 9:1 extrusion at 340°C followed by a 16:1 extrusion at 400°C, utilizing RS powders which have also been characterized utilizing electron microscopy.

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