Application of a portable indentation rig with Rockwell indenter to determine mechanical properties and residual stresses on an aluminum plate

2020 ◽  
Vol 55 (7-8) ◽  
pp. 246-257
Author(s):  
Saba Salmani Ghanbari ◽  
Amir-Hossein Mahmoudi
Keyword(s):  
Mechanical Properties ◽  
Residual Stresses ◽  
Structural Integrity ◽  
Indentation Load ◽  
Instrumented Indentation ◽  
Unknown Parameters ◽  
Plastic Properties ◽  
Wide Range ◽  
Portable Apparatus ◽  
Non Destructive

Measuring residual stresses is still a dilemma in many engineering applications. It is even more crucial when the industrial requirements demand for a non-destructive technique in order to avoid compromising the structural integrity of the engineering components. Furthermore, estimating the mechanical properties of the materials, especially when the components are aged, is of importance. Instrumented indentation has gained much interest in recent years. There are many studies in the literature which are focused on measuring residual stresses or mechanical properties using instrumented indentation. Since in many cases there is no possibility of transferring large samples or those under service, for possible measurements, having a portable rig can be very useful. Furthermore, indentation procedure is a low-cost non-destructive method with high accuracy which is able to measure the plastic properties of material as well as its residual stresses on which the designing and construction of the portable apparatus were based. The instrumented indentation testing details were followed according to the ASTM E2546-15 standard practice. In this research, a wide range of simulations were performed on a group of aluminum alloys in order to estimate the equi-biaxial residual stresses by analyzing the indentation load–displacement curves which were obtained from the experimental outcomes. Then neural networks were employed to estimate the unknown parameters. The performance accuracy of the designed portable apparatus and the acceptable precision of the introduced method were then verified with experimental tests performed on Al 2024-T351.

Instrumented Indentation Technique to Measure Flow Properties: A Novel Way to Enhance the Accuracy of Integrity Assessment

2003 ◽  
Author(s):  
Jae-Il Jang ◽  
Yeol Choi ◽  
Yun-Hee Lee ◽  
Jung-Suk Lee ◽  
Dongil Kwon ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Crack Detection ◽  
Structural Integrity ◽  
Instrumented Indentation ◽  
Flow Properties ◽  
Integrity Assessment ◽  
Indentation Technique ◽  
Failure Assessment ◽  
Similar Vein ◽  
Non Destructive

While most in-field technologies for structural integrity diagnosis focus on precise crack detection, the instrumented indentation technique has emerged as one of the most practically useful technologies for non-destructive and quantitative in-field measurement of mechanical properties. In a similar vein, here an advanced indentation technique for determining tensile properties and its application to structural integrity assessment are introduced and discussed. This novel indentation technique can enhance the accuracy of fitness-for-service (FFS) assessment by application to failure assessment diagram (FAD) construction.

Absence of one-to-one correspondence between elastoplastic properties and sharp-indentation load–penetration data

2005 ◽  
Vol 20 (2) ◽  
pp. 432-437 ◽  
Author(s):  
J. Alkorta ◽  
J.M. Martínez-Esnaola ◽  
J. Gil Sevillano
Keyword(s):  
Mechanical Properties ◽  
Indentation Load ◽  
Real Contact Area ◽  
Instrumented Indentation ◽  
Penetration Curve ◽  
Plastic Properties ◽  
The Real ◽  
Elastoplastic Properties ◽  
Acta Mater ◽  
Penetration Data

The connection between parameters that can be measured by means of instrumented indentation with the real mechanical properties has been a matter of discussion for several years. In fact, even hardness is not a readily measurable magnitude since the real contact area depends on both the elastic and plastic properties of the sample. Recently, Dao et al. [ Acta Mater49, 3899 (2001)] proposed a method based on numerical fittings to calculate by a forward-reverse algorithm the elastoplastic properties of a sample from the load-penetration curve obtained with a sharp indenter. This work will show, in contrast, that it is not possible to measure uniquely these mechanical properties of a sample in that way.

Advanced Indentation Techniques: NDE for Flow Properties and Residual Stresses of Pipelines

2002 ◽  
Author(s):  
Yeol Choi ◽  
Dongil Son ◽  
Jae-Il Jang ◽  
Joon Park ◽  
Woo-Sik Kim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Residual Stresses ◽  
Structural Integrity ◽  
Potential Method ◽  
Indentation Load ◽  
Welding Residual Stress ◽  
Destructive Testing ◽  
Integrity Assessment ◽  
Indentation Technique

Structural integrity assessment is indispensable for preventing catastrophic failure of industrial structures/components/facilities that are faced with time-dependent and environmentally-accelerated degradation. This diagnosis of operating components should be done periodically for safe maintenance and economical repair. However, conventional standard methods for mechanical properties have the problems of bulky specimen, destructive and complex procedure of specimen sampling. So, an advanced indentation technique has been developed as a potential method for non-destructive testing of in-field structures. This technique measures indentation load-depth curve during indentation and analyzes the mechanical properties related to deformation such as yield strength, tensile strength and work-hardening index. Also the advanced indentation technique can evaluate residual stresses based on the concept that indentation load-depth curves were shifted with the direction and the magnitude of residual stress applied to materials. In this study, we characterized the tensile properties and welding residual stress of various Industrial pipeline steels through the new techniques, and the results are introduced and discussed.

Control of properties and structure of steel vessels by cooling in various media at the outlet of rolling and pressing lines

2021 ◽  
pp. 34-38
Author(s):  
R. L. Shatalov ◽  
V. A. Medvedev
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Metal Structure ◽  
Machine Building ◽  
Regression Equations ◽  
Wide Range ◽  
Industrial Mineral ◽  
Cooling Media ◽  
Technological Limitations ◽  
Non Destructive

When controlling the mechanical properties and structure of vessels made of carbon structural steels manufactured by hot deformation on rolling and pressing lines (PPL) of machine-building enterprises of Russia, such cooling media as water, I20 industrial mineral oil, air are used. The applied cooling media are able to provide the workpieces with a given structure with a wide range of mechanical properties. However, the cooling media have a number of technological limitations and conditions of the use, non-compliance with which leads to reject. When cooled in oil, the probability of ignition is high; when cooled in water, hardening cracks may form, and air is not always able to provide the required rate and uniformity of heat transfer to the environment. The efficiency of control of physical and mechanical properties and structure of deformed vessels made of 50 steel by cooling in TERMAT polymer aqueous solutions in different concentrations on PPL of the plant of JSC NPO Pribor was studied. The effect of varying the concentration from 2 to 9% of TERMAT polymer on the formation of metal structure, as well as physical and mechanical properties of hot-deformed vessels was studied. The results of testing the strength and plastic characteristics of vessels by destructive and non-destructive control methods are presented. According to the results of physical and mechanical properties, regression equations were obtained with at least 95% reliability of R2, which establish the relationship between the controlled plastic and strength parameters of the vessel metal`s properties. The conducted researches allowed to compare the indicators of the main physical and mechanical properties of steel vessels at the PPL outlet and to propose methods of inhomogeneity control that reduce time and material costs by 5–10% during the tests.

scholarly journals Numerical verification for instrumented spherical indentation techniques in determining the plastic properties of materials

2009 ◽  
Vol 24 (12) ◽  
pp. 3653-3663 ◽  
Author(s):  
Taihua Zhang ◽  
Peng Jiang ◽  
Yihui Feng ◽  
Rong Yang
Keyword(s):  
Numerical Experiments ◽  
Spherical Indentation ◽  
Numerical Verification ◽  
Instrumented Indentation ◽  
Plastic Properties ◽  
Wide Range ◽  
Validity Range ◽  
Indentation Tests ◽  
Properties Of Materials ◽  
Indentation Methods

Instrumented indentation tests have been widely adopted for elastic modulus determination. Recently, a number of indentation-based methods for plastic properties characterization have been proposed, and rigorous verification is absolutely necessary for their wide application. In view of the advantages of spherical indentation compared with conical indentation in determining plastic properties, this study mainly concerns verification of spherical indentation methods. Five convenient and simple models were selected for this purpose, and numerical experiments for a wide range of materials are carried out to identify their accuracy and sensitivity characteristics. The verification results show that four of these five methods can give relatively accurate and stable results within a certain material domain, which is defined as their validity range and has been summarized for each method.

Material characterization for laminated glass composite panel

2017 ◽  
Vol 1 (81) ◽  
pp. 11-17 ◽  
Author(s):  
K. Väer ◽  
J. Anton ◽  
A. Klauson ◽  
M. Eerme ◽  
E. Õunapuu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Wave Propagation ◽  
Residual Stresses ◽  
Material Properties ◽  
Composite Panel ◽  
Laminated Glass ◽  
Glass Composite ◽  
Private Company ◽  
Viscoelastic Interlayer ◽  
Non Destructive

Purpose: Laminated glass composite panel (LGCP) with at least one flexible plastic/ viscoelastic interlayer is considered. The purpose of this paper is to determine the material properties of the constituents of LGCP required for accurate modelling of the laminated glass structures. Design/methodology/approach: The proposed approach includes the following three type of tests: non-destructive tests for determining mechanical properties of the glass layers (based on wave propagation), mechanical tests and finite element simulations for determining properties of the interlayers, measuring residual stresses in glass layers using novel methods and equipment (non-destructive, wave propagation based). Findings: Methodology and procedures for determining material properties of the LGCP. Research limitations/implications: Due to fact that the shear moduli of the viscoelastic interlayers and glass skin layers differs up to thousands times, the direct application of the classical sandwich theory may lead to inaccurate results. The layer wise plate theory with viscoelastic interlayer should be applied. In the case of layer wise theory, the material properties should be determined for each layer (not averaged properties for laminate only). Practical implications: The proposed approach allows to determine the properties of the LGCP components with high accuracy and form base for development of accurate plate model for modelling vibration, buckling and bending of the LGCP. The effect of the residual stresses is most commonly omitted in engineering applications. However, in the case of tempered glass the residual stresses are significant and have obviously impact on stress- strain behaviour of the laminated glass panel. Originality/value: Study consists of valuable parts, i.e. determining residual stresses in glass performed in cooperation with private company GlasStress Ltd. Special software and measuring equipment are developed. Further LGCP interlayer mechanical properties are tested experimentally and using simulation tools for design optimization purposes.

The Influence of Spraying Parameters on Stresses and Mechanical Properties of HVOF-Sprayed Co-Cr-W-C Coatings

2014 ◽  
Vol 606 ◽  
pp. 171-174 ◽  
Author(s):  
Jiří Matějíček ◽  
Šárka Houdková ◽  
Olga Bláhová ◽  
Zdenek Pala
Keyword(s):  
Mechanical Properties ◽  
Residual Stresses ◽  
Particle Temperature ◽  
Instrumented Indentation ◽  
Stellite 6 ◽  
Young’S Moduli ◽  
Particle Characteristics ◽  
Spraying Parameters ◽  
The Relationship

Stellite 6 Co-Cr-W-C coatings were sprayed by HVOF while systematically varying the spraying parameters, namely the equivalent ratio and combustion pressure. During spraying, the in-flight particle temperature and velocity were measured. Deposition, thermal and residual stresses were determined by in-situ curvature monitoring of the sprayed samples. Young's moduli and hardness of the coatings were determined by instrumented indentation. The relationship between spraying parameters, in-flight particle characteristics and mechanical properties is discussed.

Mechanical properties from instrumented indentation: Uncertainties due to tip-shape correction

1998 ◽  
Vol 13 (10) ◽  
pp. 2936-2944 ◽  
Author(s):  
L. E. Seitzman
Keyword(s):  
Mechanical Properties ◽  
Indentation Load ◽  
Indentation Modulus ◽  
Statistical Uncertainty ◽  
Constant Modulus ◽  
Vickers Indentation ◽  
Instrumented Indentation ◽  
Shape Correction ◽  
Load Displacement

The quality of hardness H and indentation modulus E* measurements from instrumented indentation is investigated. Load-displacement data from glass and sapphire are obtained by Vickers indentation and converted to H and E* through a series of equations, including those for tip-shape correction. The quality of H and E* is determined by calculating the statistical uncertainty at each step and propagating the uncertainty to the next step. Conventional tip-shape corrections, assuming either constant hardness or constant modulus, introduce significant errors in H and E* when single, continuous correction functions are used. Piecewise correction functions are shown to improve the quality of H and E*. This investigation demonstrates the importance of calculating and propagating uncertainty at each step when converting instrumented indentation load-displacement data to mechanical properties.

scholarly journals Two-Photon Polymerized Poly(2-Ethyl-2-Oxazoline) Hydrogel 3D Microstructures with Tunable Mechanical Properties for Tissue Engineering

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5066
Author(s):  
Steffen Czich ◽  
Thomas Wloka ◽  
Holger Rothe ◽  
Jürgen Rost ◽  
Felix Penzold ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Computer Aided Design ◽  
Evaluation Method ◽  
Structural Integrity ◽  
Viscoelastic Behavior ◽  
Main Task ◽  
Two Photon ◽  
Wide Range ◽  
Tunable Mechanical Properties

The main task of tissue engineering (TE) is to reproduce, replicate, and mimic all kinds of tissues in the human body. Nowadays, it has been proven useful in TE to mimic the natural extracellular matrix (ECM) by an artificial ECM (scaffold) based on synthetic or natural biomaterials to regenerate the physiological tissue/organ architecture and function. Hydrogels have gained interest in the TE community because of their ability to absorb water similar to physiological tissues, thus mechanically simulating the ECM. In this work, we present a novel hydrogel platform based on poly(2-ethyl-2-oxazoline)s, which can be processed to 3D microstructures via two-photon polymerization (2PP) with tunable mechanical properties using monomers and crosslinker with different degrees of polymerization (DP) for future applications in TE. The ideal parameters (laser power and writing speed) for optimal polymerization via 2PP were obtained using a specially developed evaluation method in which the obtained structures were binarized and compared to the computer-aided design (CAD) model. This evaluation was performed for each composition. We found that it was possible to tune the mechanical properties not only by application of different laser parameters but also by mixing poly(2-ethyl-2-oxazoline)s with different chain lengths and variation of the crosslink density. In addition, the swelling behavior of different fabricated hydrogels were investigated. To gain more insight into the viscoelastic behavior of different fabricated materials, stress relaxation tests via nanoindentation experiments were performed. These new hydrogels can be processed to 3D microstructures with high structural integrity using optimal laser parameter settings, opening a wide range of application properties in TE for this material platform.

Mechanical Properties of Wood and Timber Bridge Evaluation

2014 ◽  
Vol 587-589 ◽  
pp. 1381-1385
Author(s):  
Ling Ling Yu ◽  
Jie Jun Wang ◽  
Te Huang
Keyword(s):  
Mechanical Properties ◽  
Structural Integrity ◽  
Strength Properties ◽  
Structural Elements ◽  
Bridge Evaluation ◽  
Bridge Structures ◽  
And Performance ◽  
Inspection Techniques ◽  
Non Destructive ◽  
Timber Bridges

Wood possesses material properties that may be significantly different from other materials normally encountered in structural design. It is necessary for the engineer to have a general understanding of the properties and characteristics that affect the strength and performance of wood in bridge applications. This paper discusses the mechanical properties of wood, including elastics properties and strength properties. Timber bridge are often exposed to harsh environment conditions. Over time, this exposure can lead to deterioration. In turn, this deterioration may lead to a loss of structural integrity that is detrimental to the structure and its users. Timber structural elements are susceptible to degradation due to environmental and loading conditions. A variety of inspection techniques can be employed to locate damage and decay in timber members in order to maintain structural performance. Methods of non-destructive techniques for timber bridges are getting more and more important. This paper presents several non-destructive methods to timber bridge structures.

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