A Reliability-Based Approach to Assess Fatigue Behaviour Based on Small Incomplete Data Sets

2008 ◽  
Vol 44-46 ◽  
pp. 871-878 ◽  
Author(s):  
Chu Yang Luo ◽  
Jun Jiang Xiong ◽  
R.A. Shenoi
Keyword(s):  
Incomplete Data ◽  
Standard Procedure ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Small Sample ◽  
Data Sets ◽  
Safe Life ◽  
A New Technique ◽  
And Performance

This paper outlines a new technique to address the paucity of data in determining fatigue life and performance based on reliability concepts. Two new randomized models are presented for estimating the safe life and pS-N curve, by using the standard procedure for statistical analysis and dealing with small sample numbers of incomplete data. The confidence level formulations for the safe and p-S-N curve are also given. The concepts are then applied for the determination of the safe life and p-S-N curve. Two sets of fatigue tests for the safe life and p-S-N curve are conducted to validate the presented method, demonstrating the practical use of the proposed technique.

Single-point likelihood method to determine a generalized S-N surface

2006 ◽  
Vol 220 (10) ◽  
pp. 1519-1529 ◽  
Author(s):  
J J Xiong ◽  
R A Shenol
Keyword(s):  
Confidence Level ◽  
Single Point ◽  
Small Sample ◽  
Likelihood Method ◽  
Fatigue Reliability ◽  
Reliability Design ◽  
S Curve ◽  
A New Technique ◽  
Economic Use

This paper outlines a new technique to address the paucity of data in determining a generalized S-N surface on the basis of fatigue reliability design. A new single-point likelihood method (SPLM) is presented for estimating a P-S-N curve, dealing with small sample numbers of data. A confidence level formula for P-S-N curve estimated by SPLM is also given. The concepts are then applied for the determination of a generalized S-N surface. Finally, contrast tests for the P-S curve are conducted to examine the presented method, demonstrating the practical and economic use of the proposed technique. It is shown from the results that the P-S-N curve can be obtained realistically using small sample numbers and that the required number of test specimens in this case is less than those for the conventional method.

Fatigue Crack Growth Experiments of Resonating Micro-Samples

2007 ◽  
Vol 345-346 ◽  
pp. 817-820
Author(s):  
Andrea Cambruzzi ◽  
Jürg Dual
Keyword(s):  
Crack Growth ◽  
Fatigue Behaviour ◽  
Phase Lock Loop ◽  
Fatigue Tests ◽  
Crack Growth Behavior ◽  
Micro Electro Mechanical Systems ◽  
Micro Scale ◽  
Growth Experiments

The reliability and optimal design of Micro Electro Mechanical Systems (MEMS) can be achieved only with the determination of material properties at the micro-scale. The major challenges in performing fatigue tests at the micro-scale are related to the accurate measurement of tiny deformations, to the control of very low forces and to the preparation, handling and positioning of μm-sized samples. In order to investigate the fatigue behaviour of MEMS components a new experimental setup based on the Phase Lock Loop (PLL) technique and a continuum mechanical model were developed for the characterization of micro-sized test samples. The main advantage of PLL is the achievable resolution in the crack length measurement, which increases with the decreasing of specimen size. Therefore, micro-beams with notches and without notches were prepared by electroplating Nickel in a SU8 photoresist mold (UV-LIGA). Investigations on the initiation and near-threshold crack growth behavior were performed to improve the understanding of the micro-mechanisms involved in fatigue phenomena.

scholarly journals A 3D Cascaded Spectral–Spatial Element Attention Network for Hyperspectral Image Classification

2021 ◽  
Vol 13 (13) ◽  
pp. 2451
Author(s):  
Huaiping Yan ◽  
Jun Wang ◽  
Lei Tang ◽  
Erlei Zhang ◽  
Kun Yan ◽  
...  
Keyword(s):  
Hyperspectral Image ◽  
Training Sample ◽  
Small Sample ◽  
Data Sets ◽  
Attention Network ◽  
Deep Network ◽  
Public Data ◽  
Comparable Performance ◽  
And Performance ◽  
Spatial Element

Most traditional hyperspectral image (HSI) classification methods relied on hand-crafted or shallow-based descriptors, which limits their applicability and performance. Recently, deep learning has gradually become the mainstream method of HSI classification, because it can automatically extract deep abstract features for classification. However, it remains a challenge to learn more meaningful features for HSI classification from a small training sample set. In this paper, a 3D cascaded spectral–spatial element attention network (3D-CSSEAN) is proposed to solve this issue. The 3D-CSSEAN integrates the spectral–spatial feature extraction and attention area extraction for HSI classification. Two element attention modules in the 3D-CSSEAN enable the deep network to focus on primary spectral features and meaningful spatial features. All attention modules are implemented though several simple activation operations and elementwise multiplication operations. In this way, the training parameters of the network are not added too much, which also makes the network structure suitable for small sample learning. The adopted module cascading pattern not only reduces the computational burden in the deep network but can also be easily operated via plug–expand–play. Experimental results on three public data sets show that the proposed 3D-CSSEAN achieved comparable performance with the state-of-the-art methods.

Direct phase determination in electron crystallography: small organic molecules

1992 ◽  
Vol 50 (2) ◽  
pp. 1166-1167
Author(s):  
Douglas L. Dorset
Keyword(s):  
Organic Molecules ◽  
Data Sets ◽  
Temperature Structure ◽  
3D Analysis ◽  
Intensity Data ◽  
Electron Crystallography ◽  
Phase Determination ◽  
Measured Intensity ◽  
3D Data

The quantitative use of electron diffraction intensity data for the determination of crystal structures represents the pioneering achievement in the electron crystallography of organic molecules, an effort largely begun by B. K. Vainshtein and his co-workers. However, despite numerous representative structure analyses yielding results consistent with X-ray determination, this entire effort was viewed with considerable mistrust by many crystallographers. This was no doubt due to the rather high crystallographic R-factors reported for some structures and, more importantly, the failure to convince many skeptics that the measured intensity data were adequate for ab initio structure determinations.We have recently demonstrated the utility of these data sets for structure analyses by direct phase determination based on the probabilistic estimate of three- and four-phase structure invariant sums. Examples include the structure of diketopiperazine using Vainshtein's 3D data, a similar 3D analysis of the room temperature structure of thiourea, and a zonal determination of the urea structure, the latter also based on data collected by the Moscow group.

Techniques for Determining the Parameters of a Two-Dimensional Tire Model for the Study of Ride Comfort

1997 ◽  
Vol 25 (3) ◽  
pp. 187-213 ◽  
Author(s):  
F. Mancosu ◽  
G. Matrascia ◽  
F. Cheli
Keyword(s):  
Physical Properties ◽  
Ride Comfort ◽  
Dynamic Test ◽  
Longitudinal Direction ◽  
Tire Model ◽  
Rigid Ring ◽  
Ring Model ◽  
Mass Moment ◽  
A New Technique ◽  
And Performance

Abstract A rigid ring model of the tire for the study of in-plane dynamics and a new technique for determining the parameters of the model are presented in this paper. This model can be used for studying the comfort of vehicles, problems of driving, and braking problems in the longitudinal direction. Comparison with finite element models shows that the rigid ring model of the tire is capable of describing the in-plane eigenmode shapes in the frequency range of 0–130 Hz. The well-known “brush model,” integrated into the tire model, is introduced to take into account the slide phenomena in the contact patch. The parameters of the model can be correlated with the physical properties of the tire so that designers can take advantage of such a correlation in the development of new tires in terms of time, cost, and performance. The technique used to determine the parameters of the model for some automobile tires include the direct measurements of some physical properties (mass, moment of inertia, stiffness) and a method of identification applied on the results from a dynamic test. The model is able to predict experimental data in terms of natural frequencies and relative dampings. Results from the application of this technique on two tires are reported.

The Frequency of Occurrence of Handwriting Performance Features Used to Predict Whether Questioned Signatures are Simulated

2018 ◽  
Vol 28 ◽  
pp. 35-42
Author(s):  
David Black ◽  
Bryan Found ◽  
Doug Rogers
Keyword(s):  
Large Population ◽  
Quality Parameters ◽  
Frequency Of Occurrence ◽  
Relative Speed ◽  
Simulation Process ◽  
Spatial Features ◽  
And Performance ◽  
Document Examiners ◽  
Line Trace

Forensic Document Examiners (FDEs) examine the physical morphology and performance attributes of a line trace when comparing questioned to specimen handwriting samples for the purpose of determining authorship. Along with spatial features, the elements of execution of the handwriting are thought to provide information as to whether or not a questioned sample is the product of a disguise or simulation process. Line features such as tremor, pen-lifts, blunt beginning and terminating strokes, indicators of relative speed, splicing and touch ups, are subjectively assessed and used in comparisons by FDEs and can contribute to the formation of an opinion as to the validity of a questioned sample of handwriting or signatures. In spite of the routine use of features such as these, there is little information available regarding the relative frequency of occurrence of these features in populations of disguised and simulated samples when compared to a large population of a single individual’s signature. This study describes a survey of the occurrence of these features in 46 disguised signatures, 620 simulated signatures (produced by 31 different amateur forgers) and 177 genuine signatures. It was found that the presence of splices and touch-ups were particularly good predictors of the simulation process and that all line quality parameters were potentially useful contributors in the determination of the authenticity of questioned signatures. Purchase Article - $10

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