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How coupon and element tests reduce conservativeness in element failure prediction

Chan Y. Park, Nam H. Kim, Raphael T. Haftka
2014 Reliability Engineering & System Safety  
A key question, addressed here, is what weight penalty is associated with this conservativeness and how much it can be reduced by using coupon and element tests.  ...  In this paper, a probabilistic approach is used to estimate the conservative element failure strength by quantifying uncertainty in the element strength prediction.  ...  Increasing the number of coupon tests can reduce the uncertainty in the coupon test, and the uncertainty in the failure theory can be reduced by increasing the number of element test.  ... 
doi:10.1016/j.ress.2013.10.012 fatcat:3jo3i5ddvfht5fsgzcpakqb2rm

Effects of Structural Tests on Aircraft Safety

Erdem Acar, Raphael T. Haftka, Nam H. Kim
2010 AIAA Journal  
uses coupon test data to predict structural failure.  ...  In particular, the paper focuses on the effect of the number of coupon tests and structural element tests on the final distribution of failure stress.  ...  The authors also wish to thank graduate students Deepti Buchi and Sriram Pattabhiraman of the University of Florida for their work on the Johnson distribution and the quantiles.  ... 
doi:10.2514/1.j050202 fatcat:gcjqnqjnk5bz3oljczg5qkswwe

Being Conservative with a Limited Number of Test Results

Jungeun An, Erdem Acar, Raphael T. Haftka, Nam H. Kim, Peter G. Ifju, Theodore F. Johnson
2008 Journal of Aircraft  
In aircraft structural design, failure stresses are obtained from coupon tests and then used to predict failure under combined loads in structural elements.  ...  It is a common practice to repeat the element tests and then select the lowest test result as a conservative estimate of the mean failure stress.  ...  In aircraft structural design, failure stresses are obtained from coupon tests and then used to predict failure under combined loads in structural elements.  ... 
doi:10.2514/1.35551 fatcat:p6bn3c7f5zhavede33kgw44jt4

New design paradigms and approaches for aircraft composite structures

F. Romano, A. Sorrentino, L. Pellone, U. Mercurio, L. Notarnicola
2018 Multiscale and Multidisciplinary Modeling Experiments and Design  
In this framework, the use of general-purpose software, in-house developed codes and dedicated testing approaches, have become part of an improved new building block and structural sizing approach, for  ...  approaches aimed at reducing the conservativisms of the current design.  ...  , and Professor Antonio Langella of University of Naples Federico II, for the execution of the mechanical tests.  ... 
doi:10.1007/s41939-018-0034-8 fatcat:ast6pnu7mfekxlyoezzzqlq3hm

Static and Fatigue Behaviour of Hexagonal Honeycomb Cores under In-plane Shear Loads

Gabriel Bianchi, Guglielmo S. Aglietti, Guy Richardson
2011 Applied Composite Materials  
These results are also discussed in relation to the observed damage and failure modes which have been reported for the statically tested specimens and for the fatigue tested specimens at various stages  ...  The results are further investigated using explicit non-linear finite element analysis to model the buckling failure mechanisms of the tested cores.  ...  Open Access This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided  ... 
doi:10.1007/s10443-010-9184-5 fatcat:gk3gpwqxmfej3lrswpnetauu7y

Tensile material properties of human rib cortical bone under quasi-static and dynamic failure loading and influence of the bone microstucture on failure characteristics [article]

Damien Subit, Eduardo del Pozo de Dios, Juan Valazquez-Ameijide, Carlos Arregui-Dalmases, Jeff Crandall
2013 arXiv   pre-print
The bone coupons were assumed isotropic, homogeneous and elastic linear, and the average Young's modulus for the quasi-static tests (13.5 GPa) and the failure stresses (quasi-static: 112 MPa, dynamic:  ...  These finite element models can now capture small geometrical features with an attempt to predict fracture.  ...  for sharing their expertise in bone coupon testing.  ... 
arXiv:1108.0390v2 fatcat:kr7y272t3bgpnbov7sgwmxk7hu

Local Flange Buckling in Plate Girders with Trapezoidal Corrugation of Web

2018 International Journal of Engineering Research and  
One of the issues raised since the steel structure was introduced in the construction industry is how to reduce the weight and cost of the component parts such as girder and beams.  ...  The results predicted using codes, numerical analysis and experimental results are compared. Index Terms-(NAS), (DSM) ,trapezoidal corrugation, British standard I.  ...  The basic concept behind the finite element analysis is that structure is divided into a finite number of elements having finite dimensions and reducing the structure having infinite degrees of freedom  ... 
doi:10.17577/ijertcon005 fatcat:xz5qyzkn3fesnmsizq4z3k2p7m

Finite Element Modelling of Cold Formed Stainless Steel Columns

M. Macdonald, J. Rhodes
2005 Acta Polytechnica  
Comparisons of the finite element results and the test results are also made with existing design specifications and conclusions are drawn on the basis of the comparisons.  ...  Stress-strain curves derived from tests and design codes are incorporated into non-linear finite element analyses of eccentrically loaded columns and the results obtained are compared with those obtained  ...  However, any differences between finite element predictions and test results are very slight and occur mainly for very short length columns.  ... 
doaj:7a948618a5ec470398df1291666537f5 fatcat:y4l4qabxmjdovpjdoucnvpnw2q

Resin treatment of free edges to aid certification of through thickness laminate strength

Timothy A. Fletcher, Tatiana Kim, Timothy J. Dodwell, Richard Butler, Robert Scheichl, Richard Newley
2016 Composite structures  
A linear FE method developed in this paper is conservative and predicts the strength of treated curved laminates to within 5% of the average test value.  ...  This significantly reduces the edge effect and delays failure. The resin edge treatment increases the strength of the curved laminate test specimens by 16%.  ...  ACKNOWLEDGEMENTS The authors would like to acknowledge the support of Jesper Ankersen (GKN Aerospace) and Vijay Sahadevan (GKN Aerospace).  ... 
doi:10.1016/j.compstruct.2016.02.074 fatcat:fmlrsf7xoffwdja7i7bof77l6q

Weibull analysis and area scaling for infrared windows

Daniel C. Harris, Brian J. Zelinski
2017 Window and Dome Technologies and Materials XV  
The two parameter Weibull Equation 1 gives more conservative predictions of survival than a three parameter equation in which there is a lower stress limit below which the probability of failure is considered  ...  FIGURE 1 . 1 Weibull Curve (Cumulative Probability of Failure) Fit to Observed Strengths (Failure Stress) of 10 Test Coupons.  ... 
doi:10.1117/12.2258537 fatcat:cy5uu4762zhhnkhsjfl7dowhay

Finite element modelling of composite structures under crushing load

Louis N.S. Chiu, Brian G. Falzon, Romain Boman, Bernard Chen, Wenyi Yan
2015 Composite structures  
It includes a more accurate determination of the characteristic length to achieve mesh objectivity in capturing intralaminar damage consisting of matrix cracking and fibre failure, a load-history dependent  ...  The developed damage model requires a set of material parameters obtained from a combination of standard and non-standard material characterisation tests.  ...  The virtual coupon was assigned with properties of T700/M21 obtained from the literature [60] [61] [62] [63] [64] and in-house testing.  ... 
doi:10.1016/j.compstruct.2015.05.008 fatcat:cacyr3pf6fhhbgcbdhrmybcefa

Compressive strength of delaminated aerospace composites

R. Butler, A. T. Rhead, W. Liu, N. Kontis
2012 Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences  
These laminates were subsequently subject to experimental compression testing and nonlinear Finite Element Analysis (FEA) using cohesive elements.  ...  Comparison of Strip model results with those from experiments indicates that the model can conservatively predict the strain at which propagation occurs to within 10% of experimental values provided (i  ...  Hunt and David Lovell during preparation of the manuscript. The second and third authors are currently supported by the EPSRC (EP/H025898/1), Airbus Operations and GKN Aerospace.  ... 
doi:10.1098/rsta.2011.0339 pmid:22431756 fatcat:rcpvk5vznzdcngvdqyktuamkmq

Composite Materials Strength Determination Within the Current Certification Methodology for Aircraft Structures

Paolo Feraboli
2009 Journal of Aircraft  
Some examples of certification by analysis supported by test evidence as well as certification by test are given, and the fundamental differences are highlighted in the context of the building block philosophy  ...  Although several composite failure criteria have been proposed over the years to predict the static strength of polymer composites, including micromechanical and first-ply failure theories, none of them  ...  work and for their commitment to composite safety and certification. Undergraduate student researcher Enrique Galgana is gratefully acknowledged for generating the graphics.  ... 
doi:10.2514/1.41286 fatcat:5o5ga5oq3fdxvaxnv4t4nwoksu

Estimating S-N curves for local fiber dominated fatigue failure in ring specimens representing filament wound pressure vessels with damage

Eivind Hugaas, Andreas T. Echtermeyer
2021 Composites Part C: Open Access  
The local S-N curve was considerably less conservative than nominal S-N curves obtained from standard coupon testing. Its origin was a factor 2.5 higher.  ...  This study shows how S-N curves can be measured that describe local fiber dominated fatigue failure on the scale of 0.25 mm near stress concentrations caused by a hole representing damage.  ...  partners from research, industry and public sector.  ... 
doi:10.1016/j.jcomc.2021.100135 fatcat:4xkcfgi74zcfhgrhmh7cignb5e

Testing, simulation and design of cold-formed stainless steel CHS columns

Craig Buchanan, Esther Real, Leroy Gardner
2018 Thin-walled structures  
From the limited existing test data on stainless steel circular hollow sections (CHS) columns it has been observed that the current Eurocode 3 provisions can be unconservative in their capacity predictions  ...  , 9 duplex and 11 ferritic stainless steel CHS column buckling tests and 10 stub column tests have been carried out.  ...  authors would like to acknowledge the contribution of Gordon Herbert, Alfredo Olivo, Hayden Spektor and Joel Thomas at Imperial College London and Tomás García, Jordi Lafuente, Jordi Cabrerizo and Itsaso  ... 
doi:10.1016/j.tws.2018.05.006 fatcat:5twtlheb5fhsvnlnn3e4yz27ja
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