Re-Examining the Bulge Test: Methods for Improving Accuracy and Reliability

1991 ◽  
Vol 239 ◽  
Author(s):  
Martha K. Small ◽  
Joost J. Vlassak ◽  
William D. Nix
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Tensile Tests ◽  
Test Methods ◽  
Tension Test ◽  
Bulge Test ◽  
Test Results ◽  
Bulk Materials ◽  
Test Technique ◽  
Improving Accuracy

ABSTRACTSince its first application to thin films in the 1950's, the bulge test has had a prominent place in the field of thin film mechanical properties. The major appeal of the technique is that it is analogous to the familiar uniaxial tension test, which is commonly applied to bulk materials. At the same time, it avoids the sample tearing and alignment problems associated with micro-tensile tests. Unfortunately, bulge test results have been sometimes controversial and difficult to reproduce. In this paper we address possible causes for mese inconsistencies and describe a method by which the bulge test technique can be made to produce accurate and reliable results.

Mechanical Behavior of Ti-6Al-4V Manufactured by Electron Beam Additive Fabrication

2013 ◽  
Author(s):  
Leila Ladani ◽  
Lalit Roy
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Lead Time ◽  
Aerospace Industry ◽  
Tensile Tests ◽  
Test Results ◽  
Great Resistance ◽  
Additive Fabrication ◽  
Anisotropy Effect ◽  
The Cost

Additive Layer Fabrication, in particular Electron Beam Additive Fabrication (EBAF), has recently drawn much attention for its special usability to fabricate intricately designed parts as a whole. It not only increases the production rate which reduces the production lead time but also reduces the cost by minimizing the amount of waste material to a great extent. Ti6Al4V is the most common type of material that is currently being fabricated using EBAF technique. This material has been used in aerospace industry for several reasons such as excellent mechanical properties, low density, great resistance to corrosion, and non-magnetism. The effects of build direction of layers (namely, addition of layers along one of the x, y & z directions with respect to the build table) and the anisotropy effect caused by it has not been explored vigorously. This anisotropy effect has been investigated in this work. Different mechanical properties such as Yield Strength (YS), Ultimate Tensile Strength (UTS), and Modulus of Elasticity (E) of these three types of Ti6Al4V are determined using tensile tests and are compared with literature. The tensile test results show that YS and UTS for flat-build samples have distinguishably higher values than those of the side-build and top-build samples.

Application of Small Punch Test to Evaluate Tensile Properties of SA213T22 Grade Boiler Steel

2015 ◽  
Vol 830-831 ◽  
pp. 191-194
Author(s):  
M. Venkateswara Rao
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Tensile Properties ◽  
Test Methods ◽  
Uniaxial Tensile ◽  
Test Results ◽  
Small Punch Test ◽  
Small Punch ◽  
Punch Test ◽  
Aging Phenomena

Conventional tensile test methods are used for service exposed high temperature boiler tubes to evaluate the deterioration in mechanical properties such as tensile strength, yield strength and percentage elongation. The mechanical properties are required to be evaluated periodically as the boiler components undergo material degradation due to aging phenomena. The aging phenomena occurs due to continuous exposure of tubes to high temperature & pressure steam prevailing inside the tubes and high temperature exposure to corrosive combustible gases from the external surfaces within the boiler.A recent developed new technique called small punch testing has been used to evaluate the tensile properties of SA 213T22 grade steel predominantly exists in super-heater and re-heater sections of boiler. The small punch tests have been carried out on the miniature disk shaped specimens of diameter of 8.0 mm and 0.5 mm thickness extracted from both the new and service exposed tubes. Conventional uniaxial tensile tests on standard specimens from the same tube material have also been performed for comparison. The service exposed tubes showed considerable loss in mechanical properties in both the conventional and small punch test results. Correlations of tensile properties have been obtained based on the comparative analysis of both small punch and uniaxial tensile test results. Further, the study showed that an appropriate empirical relation could be generated for new and service exposed materials between both the techniques. Conventional test methods require large quantity of material removal for test samples from in-service components whereas small punch test method needs only a miniature sample extraction. This small punch test technique could also be extended to evaluate the thicker section boiler components such as pipelines and headers in the boiler as a part of remaining life assessment study. Also this technique could be a useful tool to any metallic component where large quantity of sample removal may be difficult or may not be feasible.

Measurement of Young's Modulus and Poisson's Ratio of Thin Film by Combination of Bulge Test and Nano-Indentation

2008 ◽  
Vol 33-37 ◽  
pp. 969-974 ◽  
Author(s):  
Bong Bu Jung ◽  
Seong Hyun Ko ◽  
Hun Kee Lee ◽  
Hyun Chul Park
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Applied Pressure ◽  
Indentation Test ◽  
Poisson's Ratio ◽  
Bulge Test ◽  
Nano Indentation

This paper will discuss two different techniques to measure mechanical properties of thin film, bulge test and nano-indentation test. In the bulge test, uniform pressure applies to one side of thin film. Measurement of the membrane deflection as a function of the applied pressure allows one to determine the mechanical properties such as the elastic modulus and the residual stress. Nano-indentation measurements are accomplished by pushing the indenter tip into a sample and then withdrawing it, recording the force required as a function of position. . In this study, modified King’s model can be used to estimate the mechanical properties of the thin film in order to avoid the effect of substrates. Both techniques can be used to determine Young’s modulus or Poisson’s ratio, but in both cases knowledge of the other variables is needed. However, the mathematical relationship between the modulus and Poisson's ratio is different for the two experimental techniques. Hence, achieving agreement between the techniques means that the modulus and Poisson’s ratio and Young’s modulus of thin films can be determined with no a priori knowledge of either.

scholarly journals Experimental Investigation into Corrosion Effect on Mechanical Properties of High Strength Steel Bars under Dynamic Loadings

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Hui Chen ◽  
Jinjin Zhang ◽  
Jin Yang ◽  
Feilong Ye
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Dynamic Loading ◽  
High Strength Steel ◽  
High Strength ◽  
Tensile Tests ◽  
Reinforcing Steel ◽  
Test Results ◽  
Cross Sectional ◽  
Steel Bars

The tensile behaviors of corroded steel bars are important in the capacity evaluation of corroded reinforced concrete structures. The present paper studies the mechanical behavior of the corroded high strength reinforcing steel bars under static and dynamic loading. High strength reinforcing steel bars were corroded by using accelerated corrosion methods and the tensile tests were carried out under different strain rates. The results showed that the mechanical properties of corroded high strength steel bars were strain rate dependent, and the strain rate effect decreased with the increase of corrosion degree. The decreased nominal yield and ultimate strengths were mainly caused by the reduction of cross-sectional areas, and the decreased ultimate deformation and the shortened yield plateau resulted from the intensified stress concentration at the nonuniform reduction. Based on the test results, reduction factors were proposed to relate the tensile behaviors with the corrosion degree and strain rate for corroded bars. A modified Johnson-Cook strength model of corroded high strength steel bars under dynamic loading was proposed by taking into account the influence of corrosion degree. Comparison between the model and test results showed that proposed model properly describes the dynamic response of the corroded high strength rebars.

Methods to improve reliability of bulge test technique to extract mechanical properties of thin films

2010 ◽  
Vol 50 (9-11) ◽  
pp. 1888-1893 ◽  
Author(s):  
H. Youssef ◽  
A. Ferrand ◽  
P. Calmon ◽  
P. Pons ◽  
R. Plana
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Bulge Test ◽  
Test Technique ◽  
Improve Reliability

Mechanical properties of polymer thin film measured by the bulge test

2007 ◽  
Vol 515 (18) ◽  
pp. 7222-7226 ◽  
Author(s):  
C.K. Huang ◽  
W.M. Lou ◽  
C.J. Tsai ◽  
Tung-Chuan Wu ◽  
Hung-Yi Lin
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Bulge Test ◽  
Polymer Thin Film

Measurement of Mechanical Properties of Electroplated Nickel Thin Film

2004 ◽  
Vol 261-263 ◽  
pp. 417-422 ◽  
Author(s):  
Dong Cheon Baek ◽  
Tae Sang Park ◽  
Soon Bok Lee
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Indentation Test ◽  
Ccd Camera ◽  
Aging Effect ◽  
Tension Test ◽  
Micro Electro Mechanical Systems ◽  
Tracking Process ◽  
Fabrication Condition ◽  
Continuous Stiffness Measurement

Electroplated nickel manufactured via the LIGA process, offers the possibility of stronger structure and connectors in a micro electro mechanical systems (MEMS). In this study, the mechanical properties of electroplated Nickel thin film were characterized using two methods; tension test and nano-indentation test. In tension test, a linear guided motor was used as actuator and the applied force was measured using a load cell. Strain was measured with a dual microscope that obtains the displacement of two separated zone by the tracking process of the image captured with CCD camera. In indentation test, elastic modulus was measured using a CSM(continuous stiffness measurement) module. Two types of specimen were prepared in the same wafer and tested after four months of aging, which reduces the variation of properties caused by fabrication condition and aging effect. The tension specimen is 15 µm thick and 300 µm wide. The indentation specimen is also 15 µm thick. Young's modulus were measured by two different testing methods and compared quantitatively.

Analysis of the accuracy of the bulge test in determining the mechanical properties of thin films

1992 ◽  
Vol 7 (6) ◽  
pp. 1553-1563 ◽  
Author(s):  
Martha K. Small ◽  
W.D. Nix
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Mechanical Properties ◽  
Finite Element ◽  
Material Properties ◽  
Deformation Behavior ◽  
Initial Conditions ◽  
Standard Technique ◽  
Bulge Test ◽  
The Finite Element Method

Since its first application to thin films in the 1950's the bulge test has become a standard technique for measuring thin film mechanical properties. While the apparatus required for the test is simple, interpretation of the data is not. Failure to recognize this fact has led to inconsistencies in the reported values of properties obtained using the bulge test. For this reason we have used the finite element method to model the deformation behavior of a thin film in a bulge test for a variety of initial conditions and material properties. In this paper we will review several of the existing models for describing the deformation behavior of a circular thin film in a bulge test, and then analyze these models in light of the finite element results. The product of this work is a set of equations and procedures for analyzing bulge test data that will improve the accuracy and reliability of this technique.

scholarly journals MINERALINIŲ MEDŽIAGŲ MECHANINIŲ SAVYBIŲ TYRIMAI, ANALIZĖ IR VERTINIMAS / RESEARCH, ANALYSIS, AND EVALUATION OF MECHANICAL PROPERTIES OF AGGREGATES

2018 ◽  
Vol 10 (0) ◽  
pp. 1-9 ◽  
Author(s):  
Lina Šneideraitienė ◽  
Daiva Žilionienė
Keyword(s):  
Mechanical Properties ◽  
Asphalt Pavement ◽  
Road Construction ◽  
Test Methods ◽  
Asphalt Mixtures ◽  
Test Results ◽  
Analysis And Evaluation ◽  
Baltic Countries ◽  
Research Analysis ◽  
Mineral Aggregates

The two Baltic countries, Lithuania and Latvia, use asphalt mixtures with granite slag that is imported from other countries to install the top layer of asphalt pavement, which is quite expensive. One of the requirements for aggregates used in road construction is mechanical properties. There are some differences between these countries based on national requirements. The article presents test methods for determining the mechanical properties of aggregates. According to them, the mechanical properties of aggregates were tested: resistance to fragmentation, wear, polishing and to wear by abrasion from studded tyre. Tested aggregates were Lithuanian dolomite quarry stone, which was made based on the developed and common technologies as well as imported granite from Ukraine. The analysis and evaluation of the test results have been carried out by the requirements for mineral aggregates of Lithuania and Latvia. Santrauka Dvi Baltijos šalys, Lietuva ir Latvija, asfalto dangos viršutiniam sluoksniui įrengti naudoja asfalto mišinius su granito skalda, kuri importuojama iš kitų šalių, o tai gana brangu. Vienas iš reikalavimų mineralinėms medžiagoms, naudojamoms kelių tiesyboje, yra mechaninės savybės. Jos minėtose šalyse pagal nacionalinius normatyvinius reikalavimus šiek tiek skiriasi. Straipsnyje pateikti mineralinių medžiagų mechaninių savybių nustatymo bandymo metodų aprašai. Pagal juos atlikti skaldų mechaninių savybių bandymai: atsparumas smūgiams, trupinimui, dėvėjimuisi, poliruojamumui (LST EN 1097-8:2009. Bandymai užpildų mechaninėms ir fizikinėms savybėms nustatyti. 8 dalis. Akmens poliruojamumo nustatymas) bei dygliuotoms padangoms. Ištirtos skaldos yra Lietuvos dolomito karjero skalda, pagaminta pagal patobulintą ir įprastą technologijas, bei granito skalda iš Ukrainos. Atlikta gautų bandymų rezultatų analizė bei vertinimas pagal Lietuvos ir Latvijos reikalavimus mineralinėms medžiagoms.

scholarly journals Mechanical properties of blueberry stems

2018 ◽  
Vol 64 (No. 4) ◽  
pp. 202-208
Author(s):  
Margus Arak ◽  
Kaarel Soots ◽  
Marge Starast ◽  
Jüri Olt
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Structural Parameters ◽  
Tensile Tests ◽  
Measuring Instrument ◽  
Test Results ◽  
Average Value ◽  
Agricultural Machines

In order to model and optimise the structural parameters of the working parts of agricultural machines, including harvesting machines, the mechanical properties of the culture harvested must be known. The purpose of this article is to determine the mechanical properties of the blueberry plant’s stem; more precisely the tensile strength and consequent elastic modulus E. In order to achieve this goal, the measuring instrument Instron 5969L2610 was used and accompanying software BlueHill 3 was used for analysing the test results. The tested blueberry plant’s stems were collected from the blueberry plantation of the Farm Marjasoo. The diameters of the stems were measured, test units were prepared, tensile tests were performed, tensile strength was determined and the elastic modulus was obtained. Average value of the elastic modulus of the blueberry (Northblue) plant’s stem remained in the range of 1268.27–1297.73 MPa.

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