scholarly journals Numerical uncertainty analysis of active and passive structures in the structural design phase

2017 ◽  
Vol 199 ◽  
pp. 1240-1245 ◽  
Author(s):  
Sushan Li ◽  
Elena Maja Slomski ◽  
Tobias Melz
Keyword(s):  
Uncertainty Analysis ◽  
Structural Design ◽  
Design Phase

scholarly journals Structural analysis by interval approach

2008 ◽  
pp. 869-880
Author(s):  
Franck Massa ◽  
Karine Mourier-Ruffin ◽  
Bertrand Lallemand ◽  
Thierry Tison
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Structural Analysis ◽  
Design Process ◽  
Structural Design ◽  
Numerical Models ◽  
Test Case ◽  
Design Phase ◽  
Deterministic Analysis ◽  
Interval Approach

Finite element simulations are well established in industry and are an essential part of the design phase for mechanical structures. Although numerical models have become more and more complex and realistic, the results can still be relatively far from observed reality. Nowadays, use of deterministic analysis is limited due to the existence of several kinds of imperfections in the different steps of the structural design process. This paper presents a general non-probabilistic methodology that uses interval sets to propagate the imperfections. This methodology incorporates sensitivity analysis and reanalysis techniques. Numerical interval results for a test case were compared to experimental interval results to demonstrate the capabilities of the proposed methodology.

Development of 3D CAD/CAE Interface in Initial Structural Design Phase of Shipbuilding

2016 ◽  
Vol 21 (2) ◽  
pp. 186-195 ◽  
Author(s):  
Myeong-Jo Son ◽  
Jeong-Youl Lee ◽  
Ho Gyun Park ◽  
Jong-Oh Kim ◽  
Jengjae Woo ◽  
...  
Keyword(s):  
Structural Design ◽  
Design Phase ◽  
3D Cad

A Dual-Purpose KBES for Preliminary Structural Design

1989 ◽  
Author(s):  
P. K. Hart ◽  
J. Rodriguez
Keyword(s):  
Structural Design ◽  
Two Dimensional ◽  
Design Phase ◽  
Optimization Scheme ◽  
Inference Mechanism ◽  
Dual Purpose ◽  
Industrial Productivity ◽  
Adequate Definition ◽  
Definition Of ◽  
Ongoing Project

Abstract A prototype expert system for automatic preliminary shape synthesis is being developed. The purpose of this system is to generate preliminary designs which can be used either for basic engineering or as an initial solution in an optimization scheme. The developed prototype intends to emulate the conceptual-design/preliminary-redesign phases in the design process. Both phases have been modularized and developed under adequate computational shells. Modules requiring heuristic support are implemented in a LISP/KEE™ environment, the ones being computer-intensive are in C subroutines. Heuristics are applied in the initial design phase to produce an adequate definition of the geometric domain. For the redesign phase, a set of options were programmed into the inference mechanism. These rules focus on molding the geometric domain. Rules for the inference mechanism, and common databases were elaborated. The two-dimensional problems of a fillet in a tension bar, and a connecting link are used to illustrate the system. This is part of an ongoing project at the Center for Computer Aids for Industrial Productivity (CAIP) in New Jersey.

scholarly journals A Mechanical Modelling and Simulation Method for Resolving PIM Problems in Antennas

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 294
Author(s):  
Chen Chen ◽  
Yangyang Gu
Keyword(s):  
Finite Element ◽  
Product Development ◽  
Structural Design ◽  
Nonlinear Distortion ◽  
Simulation Method ◽  
Design Phase ◽  
Root Cause ◽  
Element Simulation ◽  
Mechanical Modelling ◽  
The Stability

Passive intermodulation (PIM) generated from antennas is a nonlinear distortion phenomenon and causes serious problems to communication quality. Traditional radio frequency (RF) solutions focus on testing the final product to find the PIM source. However, it cannot solve the stability of PIM after the antenna is vibrated. This paper introduces a new method to improve the stability of PIM in the design phase. By studying the mechanism of PIM generation, a simulation method is proposed in this paper by applying mechanical finite element simulation and simulating the structural design of the device under test. Then, the stress at the PIM source is reduced, thereby the PIM stability of the product is improved. This paper adopts this method by studying a typical product, finding the root cause that affects the product PIM magnitude and stability, and optimizing its design. The PIM value of the new scheme is stable by making a prototype and testing. The method provided in this article can effectively improve product development efficiency and assist designers in avoiding the risks of PIM before the product’s manufacturing.

Structural Aspects of the Do 31 Jet-Lift VTOL Aircraft

1968 ◽  
Vol 72 (692) ◽  
pp. 719-734
Author(s):  
M. Flemming
Keyword(s):  
Structural Design ◽  
Near Field ◽  
Aircraft Design ◽  
Design Phase ◽  
Test Results ◽  
Structural Problems ◽  
Engine Thrust ◽  
Field Noise ◽  
The Individual ◽  
Vtol Aircraft

Summary The special structural problems of VTOL aircraft are examined, taking the Do 31 as a basis and it is shown how these problems can be solved without significant weight penalties. After a short description of the aircraft and the systems associated with aircraft testing, the structural design of the Do 31 is described. The effect of special VTOL load cases on the individual aircraft components are illustrated and it is shown where these are critical. The methods used in the calculations are explained briefly and theoretical results are compared with tests. Special emphasis is given to the lift pod structure and its structural analysis. There are special problems with VTOL aircraft which must be considered during the structural design phase. The effects of temperature on the engine pods, wing and fuselage are shown and the solution of the associated design problems are indicated. The results obtained are compared with a number of Do 31 test results. If conventional British or US fire requirements are applied to the design of lift pods, there is a possibility of some weight penalties. Fire problems and fire requirements for lift pods are discussed with reference to test results. Recommendations for minimising the danger of explosions and for the use of fire detecting devices are also made. A great advantage of VTOL aircraft is their ability to use unprepared sites. Debris may be thrown up by the downward deflected jet exhausts and strike the aircraft. Calculations and test results show the effect of impact velocities, stone shape, etc. Structural optimisation for withstanding debris impact is considered. Noise problems have to be investigated during the aircraft design phase because of the high engine thrust installed in a VTOL aircraft. Results of the Do 31 tor near field noise levels are given. Particular attention is given to the proportion of overall noise level which affects the airframe.

Uncertainty Analysis for Ship Powering Performance Prediction Based on Model Tests

2015 ◽  
Author(s):  
Baoshan Wu ◽  
Shaopeng Ji ◽  
Wentao Wang
Keyword(s):  
Uncertainty Analysis ◽  
Performance Prediction ◽  
Open Water ◽  
Model Tests ◽  
International Standards ◽  
Design Phase ◽  
Rotating Speed ◽  
Calm Water ◽  
Energy Efficiency Design Index ◽  
Resistance Tests

International standards of energy efficiency design index (EEDI) for new ships from 2013 to 2025 have been in effect and it is very importance to make preliminary verification of EEDI of a ship at its design phase. Generally, a set of ship model tests in towing tank, including resistance tests, propeller open water tests and propulsion tests, are performed. However, it is a challenge yet to analyze the uncertainty in ship performance prediction based on these model tests. In this paper, a real example of bulk carrier is presented to demonstrate implementation of the ISO GUM into uncertainty analysis for prediction such powering performance in calm water, illustrating the detailed procedure for performance of model tests and uncertainty analysis in prediction. It is shown in this example the ship speed and the propeller rotating speed at 85% MCR are predicted at the level of confidence 95% as (13.65±0.19) knots and (132.9±1.6) rpm, respectively and additionally, the significant sources of uncertainty come from the measurement of drag in resistance tests and the towing forces in propulsion tests. That means higher precision or more repeat model tests would be required to obtain higher accuracy in prediction of a ship powering performance and less uncertainty in preliminary verification of EEDI at its design phase.

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