曝光臺 注意防騙 網曝天貓店富美金盛家居專營店坑蒙拐騙欺詐消費者

parameters;
• Confidence range of the Campbell
diagram after a statistical analysis.
GRAPHICAL POST-PROCESSING
LINKING DEVICES AND SPECIALIZED ELEMENTS
• Many linking devices such as linear and non-linear bearings, squeeze-films dampers (several models), bushing, gear and control
elements (sensors and actuators) are available;
• Linear constraints and rigid bodies can be defined between degrees of freedom;
• The inertia and energy properties of a group of elements can be obtained using macro elements;
• A model-linking element is used to connect an axisymmetrical model of the rotor with a 3-D description of the fixed parts;
• Finally, routines are available in order to generate user elements.
AXISYMMETRICAL MODEL
Flexible rotors are modeled by 2-D axisymmetrical shell
or volume finite elements whose displacement field is
developed in Fourier series. With this approach, it is no
longer necessary to make a distinction between shaft
and disks.
MODELING
SAMCEF Rotor can handle rotors with different rotation
speeds and the user is free to choose the orientation of the
spin axis. We can model the fixed parts using the standard
finite element library.
Superelements (CRAIG and BAMPTON) can be used to model
either rotating or fixed parts.
Several models are available to describe rotating parts:
BEAM MODEL
Beams elements are used to model shafts with rigid disks. A
bushing element allows defining a stiffness matrix between
two nodes and can be used to model shaft coupling. The
cross-section can vary along the beam axis (hollow frustum).
LOADS
• External forces includes synchronous loads
(unbalances loads) and asynchronous loads
(gravity, maneuver loads);
• Gravity loads, imposed overall or local
acceleration;
• Radial unbalances or moments;
• Locally imposed displacements or rotations.
Materials and the Aerospace Industry
Krishnan K. Sankaran, Ph.D.
Senior Technical Fellow
Materials and Processes Technology
Boeing Phantom Works
Enhancing Innovation and Competitiveness Through
Investments in Fundamental Research
Westin Hotel, Arlington, VA
December 3-5, 2006
EOT_PW_icon.ppt | 2
Engineering, Operations & Technology | Phantom Works
Copyright © 2006 Boeing. All rights reserved.
AM&ST
Questions to Consider for Enhancing Innovation and
Competitiveness
• Expanded federal investments in research and
education and the impact
• Acceleration of ROI in basic research
• Collaboration models for research
• Specific areas of fundamental research
• Workforce challenges
EOT_PW_icon.ppt | 3
Engineering, Operations & Technology | Phantom Works
Copyright © 2006 Boeing. All rights reserved.
AM&ST
Boeing Products
EOT_PW_icon.ppt | 4
Engineering, Operations & Technology | Phantom Works
Copyright © 2006 Boeing. All rights reserved.
AM&ST
Materials Research to Meet 21st Century Defense Needs
DoD Sponsored, NRC/NMAB Study - 2003
• Revolutionary capabilities from R&D in
• Structural and multifunctional materials
• Energy and power materials
• Electronic and photonic materials
• Functional organic and hybrid materials
• Bio-derived and bio-inspired materials
• Five recommendations made
• Accelerate materials transition from concept to service
• Computational modeling
• Integrate research in various materials classes
• Discover materials with substantially improved properties
• Materials research from conception to service to retirement
EOT_PW_icon.ppt | 5
Engineering, Operations & Technology | Phantom Works
Copyright © 2006 Boeing. All rights reserved.
AM&ST
Strength and Corrosion Resistance Improvements
Relative to 7075-T651 in New 7XXX-Series Alloys
Yield
Strength
(MPa)
600
550
1940 1950 1960 1970 1980 1990 2000
7075-T651
7075-T7351
7075-T7651
7050-T7451
7150-T651 7150-T7751
7055-T7751
Year First Used in Aircraft
Corrosion Resistance
Low
Medium
High
2005
7085-T7651
Thick Products 75 - 200 mm
Thin Products < 75 mm
500
650
700
450
400
EOT_PW_icon.ppt | 6
Engineering, Operations & Technology | Phantom Works
Copyright © 2006 Boeing. All rights reserved.
AM&ST
Composition (Wt. %) of 7XXX Series Alloys
7075 7050 7055 7085
Zn 5.6 6.2 8.0 7.5
　
中國航空網 www.k6050.com
航空翻譯 www.aviation.cn
本文鏈接地址：航空資料39(51)