Improvement of analytical model using uncertain test data

AIAA Journal ◽  
1999 ◽  
Vol 37 ◽  
pp. 489-495
Author(s):  
Abdelkrim Cherki ◽  
Bertrand Lallemand ◽  
Thierry Tison ◽  
Pascal Level
Keyword(s):  
Analytical Model ◽  
Test Data

A new analytical model for reliability analysis of a launch vehicle system with limited test data

2018 ◽  
Vol 233 (9) ◽  
pp. 3482-3495
Author(s):  
V Murugesan ◽  
Sreejith Plappillimadam ◽  
VJ Saji ◽  
SS Maruthi ◽  
AK Anilkumar
Keyword(s):  
Reliability Analysis ◽  
Analytical Model ◽  
Test Data ◽  
Weighting Factor ◽  
Design Parameters ◽  
Launch Vehicles ◽  
Minimum Number ◽  
First Time ◽  
Propellant Rocket

Reliability is one of the critical design parameters for the launch vehicles and its systems. When the systems are ready to fly the first time, only limited test data are available and accordingly reliability assessed will be very low. However, in most cases, the new systems are derived and developed using the knowledge and experience gained from the heritage systems to meet the fresh challenges. Hence, the reliability assessed with the minimum number of tests done on the new system does not truly reflect the inherent reliability of the system. In this paper, an approach and a new analytical model are developed for the reliability assessment of systems with limited test data, giving an accurate weighting for the tests and flight experiences with similar systems. The method gives a systematic procedure for arriving at the weighting factor for test data of the pedigree system, with due consideration of the similarities between the systems and various factors influencing system reliability. The method is illustrated with a case study of a newly developed liquid propellant rocket system. The model is validated using the available test and flight data of two propulsion systems with adequate flight experience. The analytical model is generic in nature and can be applied to reliability analysis of any system, which has considerable similarities with a pedigree system.

Improvement of a Large Analytical Model Using Test Data

AIAA Journal ◽  
1983 ◽  
Vol 21 (8) ◽  
pp. 1168-1173 ◽  
Author(s):  
A. Berman ◽  
E. J. Nagy
Keyword(s):  
Analytical Model ◽  
Test Data

Design for Leakage in Flange Joints Under External Loads

2005 ◽  
Author(s):  
William J. Koves
Keyword(s):  
Internal Pressure ◽  
Analytical Model ◽  
Test Data ◽  
Pressure Vessel ◽  
Research Council ◽  
Bending Moments ◽  
Design Recommendations ◽  
Model Based ◽  
External Loads

This paper uses an analytical model based on the Pressure Vessel Research Council (PVRC) ROTT test gasket constants to compute leakage in gasketed flange joints subjected to internal pressure and external bending moments. The model results are compared with test data and design recommendations are made, consistent with the ASME/PVRC tightness based methodology.

An Analytical Model to Predict Condensate Retention on Horizontal Integral-Fin Tubes

1985 ◽  
Vol 107 (2) ◽  
pp. 361-368 ◽  
Author(s):  
T. M. Rudy ◽  
R. L. Webb
Keyword(s):  
Analytical Model ◽  
Test Data ◽  
Liquid Retention ◽  
Fluid Properties ◽  
Fin Tube ◽  
Fin Tubes

In this paper, the authors develop a general analytical model to predict the amount of surface that is flooded during condensation on a horizontal, integral-fin tube. The model is based on capillary equations that predict the amount of liquid rise on a vertical u-shaped channel. The space between adjacent integral fins forms such a channel. The authors compare the model to test data taken during condensation on three integral-fin tubes (748-to-1378 fpm) and a range of fluid properties. The analytical model predicts the amount of liquid retention on a horizontal, integral-fin tube within ± 10 percent over most of the data. The analysis is performed for the case of negligible vapor shear.

Effects of Crack Depth, Specimen Size, and Out-of-Plane Stress on the Fracture Toughness of Reactor Vessel Steels

1996 ◽  
Vol 118 (4) ◽  
pp. 415-423 ◽  
Author(s):  
Y.-J. Chao ◽  
P.-S. Lam
Keyword(s):  
Fracture Toughness ◽  
Analytical Model ◽  
Test Data ◽  
National Laboratory ◽  
Crack Depth ◽  
Specimen Size ◽  
Stress Criterion ◽  
Oak Ridge ◽  
Out Of Plane ◽  
Loading Parameter

Cleavage fracture toughness values for A533-B reactor pressure vessel (RPV) steel at -40°C obtained from test programs at Oak Ridge National Laboratory (ORNL) and University of Kansas (KU) are interpreted using the J-A2 analytical model. The KU test data are from smaller SENB specimens with a/w = 0.1 and 0.5. The ORNL test data are from 1) larger SENB specimens with a/w = 0.1 and 0.5, and 2) a six-point-bend cruciform specimen under either uniaxial or bi-axial loads. The analytical model is based on the critical stress criterion and takes into consideration the constraint effect using the second parameter A2 in addition to the generally accepted loading parameter J. It is demonstrated that the effects of crack depth (shallow versus deep), specimen size (small versus large), and loading type (uniaxial versus biaxial) on the fracture toughness from the test programs can be interpreted and predicted.

Extracting Modal Parameters of Constrained Structure from Free Test Data

2011 ◽  
Vol 110-116 ◽  
pp. 4198-4203
Author(s):  
Bin Wu ◽  
Yun He ◽  
Song Feng
Keyword(s):  
Normal Mode ◽  
Analytical Model ◽  
Test Data ◽  
Extraction Method ◽  
Fem Analysis ◽  
High Order ◽  
Mode Shapes ◽  
Modal Parameters ◽  
Mode Spectrum ◽  
Modal Synthesis

This study explores the method of extracting modal parameters of constrained structure from test data. The normal mode spectrum matrix constituted of low order frequencies of the structure can be derived from the free test data, while the normal mode shapes and the extra high order modes can be obtained through FEM analysis; The boundary constrains are equivalent as a kind of sub-structure, and the modal synthesis is used to extract the constrained modal parameters. Experiment and simulation are conducted and the results show that the extraction method based on the modal synthesis and which combines the experiment model and the analytical model is feasible.

Pressure Suppression Containment Design—Current State of the Art

1969 ◽  
Vol 91 (1) ◽  
pp. 13-20 ◽  
Author(s):  
D. R. Miller
Keyword(s):  
Analytical Model ◽  
Test Data ◽  
State Of The Art ◽  
Nuclear Reactors ◽  
Current State ◽  
Graphical Technique ◽  
Containment Pressure

A summary of the thermodynamic design limits for pressure suppression containments for nuclear reactors is presented. Those parameters which must adhere to tested values are tabulated and discussed. An analytical model is described and is shown to accurately predict the existing test data. A graphical technique for predicting the transient peak containment pressure, based on the model, is presented for use in containment design.

An Energy Error Estimation Method for Improving Analytical Models Using Vibration Modal Test Data

1995 ◽  
Vol 209 (2) ◽  
pp. 97-105 ◽  
Author(s):  
S Guo ◽  
N G Hemingway
Keyword(s):  
Analytical Model ◽  
Error Estimation ◽  
Test Data ◽  
Dynamic Models ◽  
Estimation Method ◽  
Analytical Models ◽  
Original Matrix ◽  
Energy Error ◽  
Modal Test ◽  
Model Improvement

When improving analytical dynamic models using modal test data, correct localization of the poorly modelled areas in the analytical model is essential for ensuring the accuracy of the model improvement obtained. In this paper, a method referred to as the energy error estimation (EEE) method is proposed. Firstly, this method is capable of effectively distinguishing the correctly modelled mass and stiffness elements from those poorly modelled regions by using a limited number of test modes. This results in an accurate localization of the analytical modelling errors. Secondly, a set of correction factors can be obtained for improving those elements that are identified as having been poorly modelled. The improved analytical model will also retain its original matrix configuration, size and physical explanation, which is desirable. In order to verify the efficiency and accuracy of this proposed method, beam examples using both simulated and experimental modal test data are demonstrated. Excellent model improvement is shown in these examples.

Sign in / Sign up

Export Citation Format

Share Document