Optimal Structural Frequency Design of Stiffened Shell

2012 ◽  
Vol 157-158 ◽  
pp. 1636-1639 ◽  
Author(s):  
Da Hai Mi ◽  
Rui Yang ◽  
Liang Zhou ◽  
Yang Liu ◽  
Dong Ming Guo
Keyword(s):  
Structural Design ◽  
Design Method ◽  
Frame Structure ◽  
Size Optimization ◽  
Optimum Structure ◽  
Regular Grid ◽  
Stiffened Shell ◽  
Evolutionary Structural Optimization ◽  
Design Variables ◽  
Test Models

Frequency-aimed optimal structural design of stiffened shell is concerned. It is a reverse design problem for the first several modal frequencies to converge to a set of target value. A design method combined modified bi-directional evolutionary structural optimization (BESO) and size optimization is presented. Optimization model consists of skin and regular grid frame structure. To solve irregular branches and holes that often exist in ordinary topology optimization results, instead of elements, the existence states of ribs in the frame are used as design variables and sensitivity of the rib is discussed. Detailed design is conducted by size optimization. Example shows that frequency requirements are achieved. And the optimum structure is regular and clear, the localized modes problem is avoid. This is very suitable for designing airplane wind tunnel flutter test models.

Frequency-Aimed Structural Optimal Design of Stiffened Plate

2012 ◽  
Vol 452-453 ◽  
pp. 1475-1480
Author(s):  
Da Hai Mi ◽  
Rui Yang ◽  
Liang Zhou ◽  
Yang Liu ◽  
Dong Ming Guo
Keyword(s):  
Optimal Design ◽  
Structural Design ◽  
Optimization Method ◽  
Frame Structure ◽  
Size Optimization ◽  
Stiffened Plate ◽  
Numerical Instability ◽  
Structure Modification ◽  
Plate Structure ◽  
Evolutionary Structural Optimization

Optimal structural design of stiffened plate structure with multi order modal frequencies objective is discussed. It is a structural reverse design problem for the first several order modal frequencies to reach a set of given value. A new method based on bi-directional evolutionary structural optimization (BESO) and size optimization is presented. To solve the porous and irregular shape problem in the optimized structure, a regular shaped grid-like frame structure optimization model is established. The bars in the frame structure are regarded as basic unites of structure modification. The bars’ sensitivity is discussed, and applied to optimization process based on frequency sensitivity. The structural optimal design process can be described as follows: the frequencies are used as the target, the volume is considered as constraint, adjacent sensitivity redistribution method is adopted to suppress numerical instability. Then size optimization method is adopted to conduct detailed design. Finally this method is applied to a stiffened plate structure. Results show that the proposed approach is feasible to achieve given multi order modal frequencies. The optimized structure consists of regular bars, so a clear structure is obtained.

Strength Model Uncertainties of Burst, Yielding, and Excessive Bending of Piping

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Kleio Avrithi ◽  
Bilal M. Ayyub
Keyword(s):  
Structural Design ◽  
Design Method ◽  
Strength Model ◽  
Allowable Stress ◽  
Model Uncertainties ◽  
Reliability Based Design ◽  
Design Variables ◽  
Strength Models ◽  
Potential Use ◽  
Allowable Stress Design

Nuclear safety-piping is designed according to the ASME Boiler and Pressure Vessel Code, Sections III, NB-, NC-, and ND-3600 that use the allowable stress design method (ASD). The potential use instead of reliability-based design equations for nuclear piping could benefit the structural design by providing, among others, consistent reliability levels for piping. For the development of such equations, not only the probabilistic characteristics of the design variables are needed, but also the quantification of the uncertainties introduced by the strength models that are used in order to estimate the resistance of pipes subjected to different loadings. This paper evaluates strength models, and therefore provides necessary information for the reliability-based design of pipes for burst or yielding due to internal pressure and for excessive bending.

Set-Based Design Method for the Early Phase Design of Structures With Uncertainties

2010 ◽  
Author(s):  
Masato Inoue ◽  
Yutaka Hattori ◽  
Haruo Ishikawa
Keyword(s):  
Structural Design ◽  
Early Phase ◽  
Design Method ◽  
Analysis Tool ◽  
Design Variables ◽  
Point Solution ◽  
Design Solutions ◽  
Set Based Design ◽  
Express Information ◽  
Analyze Structure

Since an early phase of design intrinsically contains uncertainties from various sources of variations, design performances are fluctuating or reflect uncertainty caused by uncertain design variables. Analysis tool such as finite element method (FEM) is useful for structural analysis. However, using unique point solution does not express information about uncertainties. Designers need to figure out an outline of the structural feature and have to obtain a design idea under some uncertain design information in a structural design at the early phase of design. We have proposed a preference set-based design (PSD) method that generates a ranged set of design solutions that satisfy sets of performance requirements. This study proposes a structural design method for the early phase of design based on the PSD method that is possible to analyze structure with design uncertainty by elastic FEM and obtain a ranged set of design solutions. That is, a design method for analyzing structures and obtaining a ranged set of design solutions with uncertainties of material property and dimension of structure (coordinates of geometry) under fluctuating distribution of performance characteristics of stress and displacement is proposed. In order to illustrate the availability of our approach, design problem of 3-dimensional truss structure is solved.

Optimum Structural Design of Naval Vessels

2003 ◽  
Vol 40 (03) ◽  
pp. 149-157
Author(s):  
Seo Seung II ◽  
Son Keon Ho ◽  
Park Myung Kyu
Keyword(s):  
Structural Analysis ◽  
Structural Design ◽  
Design Method ◽  
Design Standards ◽  
Naval Vessel ◽  
Main Design ◽  
Optimum Structural Design ◽  
Design Variables ◽  
Analysis Theory ◽  
The U.S

Naval vessels are not regulated by class rules, but by special regulations. This study introduces the concept and characteristics of the regulations of the U.S. Navy, which has been the most reliable in setting design standards of naval vessels and helps designers comprehend the effect of each regulation on design results. Also, an optimum structural design method combined with structural analysis theory is proposed for an actual naval vessel to be designed according to U.S. Navy regulations. The validity of the proposed method is shown by the optimum design results for the midship section. The optimum spacings of longitudinal and transverse web frames are found, and the effect of the main design variables is investigated.

Multi-Target Optimization Design of Earthquake-Resistant Structure Taking Ductility and Cost into Account

2010 ◽  
Vol 163-167 ◽  
pp. 2415-2419 ◽  
Author(s):  
Hong Sheng Zhao ◽  
Hui Ji
Keyword(s):  
Reinforced Concrete ◽  
Structural Design ◽  
Optimization Design ◽  
Design Method ◽  
Frame Structure ◽  
Reinforced Concrete Frame ◽  
Concrete Frame ◽  
Earthquake Resistant ◽  
Reinforced Concrete Frame Structure ◽  
Design Result

Using the conventional structural design methods, the design result is usually not the most economical and the most reasonable. While, using the single target structural optimization design method, duo to the only one target function to be optimized, the design result often can not meet with the multiple requirements of structural designing, furthermore its optimizing efficiency is low. So its application is limited. This paper proposes multi-target earthquake-resistant optimization design method for reinforced concrete frame structure under earthquake loading. In the optimization design approach, the ductility and cost which are two factors contradictory each other in structure designing are simultaneously taken as the target functions, and the function relation formula between them has been established, giving simultaneous consideration to the structural economy, safety and practicability. Using this design approach, the optimum cross-sectional dimensions, with the largest ductility and the lowest cost, of the reinforced concrete frame structure which is optimized under earthquake loading, can be obtained by computer. The practical examples of structure design, which have been optimized by using this approach, show that the cost of construction has been cut down by about 10% comparing with the conventional designing. The optimization process presented in this paper conforms entirely to the China national standards: “Code for Design of Reinforced Concrete Structures” (GB50010-2002) and “Code for Earthquake-resistant Design of Buildings” (GB50011). The theory and methods presented in this paper, having not only their theory meanings but their practical values, will be helpful for the structural design engineers and the researchers.

The Multi-Objective Oriented Product Design Method in the Machine Tool

2012 ◽  
Vol 544 ◽  
pp. 229-234
Author(s):  
Wei Zhan Li ◽  
Xian Ying Yang
Keyword(s):  
Machine Tool ◽  
Product Design ◽  
Structural Design ◽  
Large Scale ◽  
Design Method ◽  
Integrated Design ◽  
Frame Structure ◽  
Multi Objective ◽  
Systemic Factors

The Large-scale Laser Process Center (LLPC) is a type of Machine Tool (MT). With the LLPC as a sample, this paper analyzed the systemic factors of the MT product, built the Multi-Objective(MO) system impacting on the product design results, with the requires of MO proposed a integrated design method with a Frame Structure(FS), applied on the practical design of LLPC. By the verification from the process controlling and reality product, proved the expectation and the value of this method. It gave a reasonable guide for the structural design and cleared the product design confused stage, improved the design efficiency and the image quality of MT product, and indicated the main design process line in the product development.

An Investigation on Manufacture Method of High-Speed Wind-Tunnel Test Models Based on Stereo-Lithography Technique

2013 ◽  
Vol 753-755 ◽  
pp. 2722-2726
Author(s):  
Dang Guo Yang ◽  
Zheng Yu Zhang ◽  
Chao Wang ◽  
Wei Jun Zhu
Keyword(s):  
Wind Tunnel ◽  
Structural Design ◽  
High Speed ◽  
Complex Structure ◽  
Wind Tunnel Test ◽  
Frame Structure ◽  
Design Strength ◽  
Test Models ◽  
Metal Frame ◽  
Strength And Stiffness

The paper presents a novel manufacture method of high-speed wind-tunnel test models with internal metal frame and surface photopolymer resin based on Stereo-Lithography (SL) technique. Internal metal frame structure was designed to be of regular configurations that can be conveniently fabricated by conventionally mechanical manufacturing methods. Outer resin components were designed to meet configuration fidelity and surface quality, which were fabricated by SL facilities. Combination of aerodynamics and structure was utilized to accomplish structural design, strength and stiffness calibration and vibration analysis. It is validated that the manufacture method is suitable to construct the high-speed wind-tunnel models by some typical wind-tunnel models, especially for test models with complex structure.

scholarly journals Lightweight and maintainable rotary-wing UAV frame from configurable design to detailed design

2021 ◽  
Vol 13 (7) ◽  
pp. 168781402110349
Author(s):  
Huiqiang Guo ◽  
Mingzhe Li ◽  
Pengfei Sun ◽  
Changfeng Zhao ◽  
Wenjie Zuo ◽  
...  
Keyword(s):  
Design Method ◽  
Geometric Model ◽  
Optimization Method ◽  
Frame Structure ◽  
Manufacturing Cost ◽  
Detailed Design ◽  
High Manufacturing Cost ◽  
The Military ◽  
Rotary Wing ◽  
Novel Design

Rotary-wing unmanned aerial vehicles (UAVs) are widespread in both the military and civilian applications. However, there are still some problems for the UAV design such as the long design period, high manufacturing cost, and difficulty in maintenance. Therefore, this paper proposes a novel design method to obtain a lightweight and maintainable UAV frame from configurable design to detailed design. First, configurable design is implemented to determine the initial design domain of the UAV frame. Second, topology optimization method based on inertia relief theory is used to transform the initial geometric model into the UAV frame structure. Third, process design is considered to improve the manufacturability and maintainability of the UAV frame. Finally, dynamic drop test is used to validate the crashworthiness of the UAV frame. Therefore, a lightweight UAV frame structure composed of thin-walled parts can be obtained and the design period can be greatly reduced via the proposed method.

Innovative Use of Profiled Steel Plates for Seismic Structural Performance

2005 ◽  
Vol 8 (3) ◽  
pp. 247-257 ◽  
Author(s):  
Y. Fukumoto ◽  
T. Takaku ◽  
T. Aoki ◽  
K. A. S. Susantha
Keyword(s):  
Numerical Analysis ◽  
Seismic Performance ◽  
Structural Design ◽  
Design Method ◽  
Steel Plates ◽  
Structural Performance ◽  
Cyclic Testing ◽  
Beam Columns ◽  
Bridge Bents ◽  
Hot Rolled

This paper presents the innovative use of hot-rolled thickness-tapered mill products, longitudinally profiled (LP) plates, for the seismic performance of bridge bents of single and portal framed piers. The study involves the inelastic cyclic testing and numerical analysis of tested beam-columns and portal frames in order to evaluate the effects of tapering ratios of LP plates, penetration of yielding, and number of locally buckled panels on their structural ductility. A structural design method is proposed for the portal frames having LP panels under cyclic loadings.

Sign in / Sign up

Export Citation Format

Share Document