Deformation and failure of a film/substrate system subjected to spherical indentation: Part II. Prediction of failure modes in a thin TiN film deposited on a compliant elastic substrate

2006 ◽  
Vol 21 (3) ◽  
pp. 783-790 ◽  
Author(s):  
S. Math ◽  
V. Jayaram ◽  
S.K. Biswas
Keyword(s):  
Film Thickness ◽  
Failure Modes ◽  
Normal Load ◽  
Real Life ◽  
Plastic Substrate ◽  
Spherical Indentation ◽  
Elastic Substrate ◽  
Transform Method ◽  
Deformation And Failure ◽  
Elastic Film

We have demonstrated previously, using nanoindentation, that the film thickness and substrate plasticity, the important two external variables in the film layer, control the failure of the film in a mutually exclusive way. In this work, we used a non-iterative Hankel transform method to analyze the stresses in an elastic film bound to an elastic substrate by a no-slip boundary condition and subjected to a Hertzian traction. We vary the substrate compliance by two orders of magnitude to generate interfacial mismatch stresses, which mimic the corresponding changes found in a real-life elastic film on an elastic-plastic substrate when the hardness of the substrate is changed. The analysis is found to reproduce faithfully the experimental trends, which showed that normal load and interfacial stresses generated by strain mismatch drive different modes of fracture depending on the film thickness in a mutually exclusive way. This validation paves the way for this theoretical technique to be used to design multilayered film structures.

scholarly journals Nonslipping Contact Between a Mismatch Film and a Finite-Thickness Graded Substrate

2015 ◽  
Vol 83 (2) ◽  
Author(s):  
Chen Peijian ◽  
Chen Shaohua ◽  
Yao Yin
Keyword(s):  
Failure Modes ◽  
Finite Thickness ◽  
Interfacial Shear Stress ◽  
Modulus Ratio ◽  
Transform Method ◽  
Mismatch Strain ◽  
Elastic Film ◽  
Potential Failure ◽  
The Fourier Transform ◽  
Film Substrate

The contact behavior of an elastic film subjected to a mismatch strain on a finite-thickness graded substrate is investigated, in which the contact interface is assumed to be nonslipping and the shear modulus of the substrate varies exponentially in the thickness direction. The Fourier transform method is adopted in order to reduce the governing partial differential equations to integral ones. With the help of numerical calculation, the interfacial shear stress, the internal normal stress in the film and the stress intensity factors are predicted for cases with different material parameters and geometric ones, including the modulus ratio of the film to the substrate, the inhomogeneous feature of the graded substrate, as well as the profile of the contacting film. All the physical predictions can be used to estimate the potential failure modes of the film–substrate interface. Furthermore, it is found that the result of a finite-thickness model is significantly different from the prediction of a generally adopted half-plane one. The study should be helpful for the design of film–substrate systems in real applications.

Deformation and failure of a film/substrate system subjected to spherical indentation: Part I. Experimental validation of stresses and strains derived using Hankel transform technique in an elastic film/substrate system

2006 ◽  
Vol 21 (3) ◽  
pp. 774-782 ◽  
Author(s):  
Souvik Math ◽  
V. Jayaram ◽  
S.K. Biswas
Keyword(s):  
Failure Modes ◽  
Analytical Framework ◽  
Hankel Transform ◽  
Spherical Indentation ◽  
Stress Distributions ◽  
Deformation And Failure ◽  
Metallic Substrates ◽  
Bulk Film ◽  
Ceramic Films ◽  
Film Substrate

Our concern here is to rationalize experimental observations of failure modes brought about by indentation of hard thin ceramic films deposited on metallic substrates. By undertaking this exercise, we would like to evolve an analytical framework that can be used for designs of coatings. In Part I of the paper we develop an algorithm and test it for a model system. Using this analytical framework we address the issue of failure of columnar TiN films in Part II [J. Mater. Res.21, 783 (2006)] of the paper. In this part, we used a previously derived Hankel transform procedure to derive stress and strain in a birefringent polymer film glued to a strong substrate and subjected to spherical indentation. We measure surface radial strains using strain gauges and bulk film stresses using photo elastic technique (stress freezing). For a boundary condition based on Hertzian traction with no film interface constraint and assuming the substrate constraint to be a function of the imposed strain, the theory describes the stress distributions well. The variation in peak stresses also demonstrates the usefulness of depositing even a soft film to protect an underlying substrate.

Study on Measurement of Thin Film Thickness with Lateral Shearing Interferometry

2013 ◽  
Vol 718-720 ◽  
pp. 848-852
Author(s):  
Jun Hong Su ◽  
Ying Shi ◽  
Jin Man Ge
Keyword(s):  
Film Thickness ◽  
Transform Method ◽  
Shearing Interferometry ◽  
Platform Process ◽  
Fast Fourier Transform Method ◽  
Lateral Shearing ◽  
Phase Unwrap ◽  
Technical Indicator ◽  
Lateral Shearing Interferometry ◽  
Shearing Interference

The film thickness is an important technical indicator of film devices, and its accuracy directly affects various performances of optical components. In fabrication process of film device, fast and accurate measurement of film thickness has positive significance on product quality control. In this paper, measure film thickness with lateral shearing interferometry. Collect interferograms through structured lateral shearing interference platform, process interferogram with Fast Fourier Transform method to extract phase, unwrap the wrapped phase to achieve phase value. Finally, calculate film thickness based on lateral shearing interference principle. The thickness of sample is 119.6800nm measured by this method, basically the same with the result 120.6036nm that measured by ZYGO interferometer. This experiment shows that lateral shearing interferometry not only suit to measurement of film thickness, but also abundant high-precision method of measuring film thickness, and has high practical value.

Support Vibration Diagnostics and Limits in Gas Turbines

2016 ◽  
Author(s):  
Marcin Bielecki ◽  
Salvatore Costagliola ◽  
Piotr Gebalski
Keyword(s):  
Gas Turbine ◽  
Test Data ◽  
Gas Turbines ◽  
Failure Modes ◽  
Real Life ◽  
Reliability Function ◽  
Vibration Diagnostics ◽  
Real Life Data ◽  
Industrial Gas Turbines ◽  
Harmful Effects

The paper deliberates vibration limits for non-rotating parts in application to industrial gas turbines. As a rule such limits follow ISO 10816-4 or API616, although in field operation it is not well known relationship between these limits and failure modes. In many situations, the reliability function is not well-defined, and more comprehensive methods of determining the harmful effects of support vibrations are desirable. In the first part, the undertaken approach and the results are illustrated based on the field and theoretical experience of the authors about the failure modes related to alarm level of vibrations. Here several failure modes and diagnostics observations are illustrated with the examples of real-life data. In the second part, a statistical approach based on correlation of support vs. shaft vibrations (velocity / displacement) is demonstrated in order to assess the risk of the bearing rub. The test data for few gas turbine models produced by General Electric Oil & Gas are statistically evaluated and allow to draw an experimentally based transfer function between vibrations recorded by non-contact and seismic probes. Then the vibration limit with objectives like bearing rub is scrutinized with aid of probabilistic tools. In the third part, the attention is given to a few examples of the support vibrations — among other gas turbine with rotors supported on flexible pedestals and baseplate. Here there is determined a transfer coefficient between baseplate and bearing vibrations for specific foundation configurations. Based on the test data screening as well as analysis and case studies thereof, the conclusions about more specific vibration limits in relation to the failure modes are drawn.

Interval type-2 fuzzy inference-based failure mode and effect analysis model in a group decision-making setting

Kybernetes ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
İlker Gölcük
Keyword(s):  
Failure Modes ◽  
Fuzzy Inference ◽  
Real Life ◽  
Effect Analysis ◽  
Inference System ◽  
Content Type ◽  
Proposed Model ◽  
Interval Type

PurposeThis paper proposes an integrated IT2F-FMEA model under a group decision-making setting. In risk assessment models, experts' evaluations are often aggregated beforehand, and necessary computations are performed, which in turn, may cause a loss of information and valuable individual opinions. The proposed integrated IT2F-FMEA model aims to calculate risk priority numbers from the experts' evaluations and then fuse experts' judgments using a novel integrated model.Design/methodology/approachThis paper presents a novel failure mode and effect analysis (FMEA) model by integrating the fuzzy inference system, best-worst method (BWM) and weighted aggregated sum-product assessment (WASPAS) methods under interval type-2 fuzzy (IT2F) environment. The proposed FMEA approach utilizes the Mamdani-type IT2F inference system to calculate risk priority numbers. The individual FMEA results are combined by using integrated IT2F-BWM and IT2F-WASPAS methods.FindingsThe proposed model is implemented in a real-life case study in the furniture industry. According to the case study, fifteen failure modes are considered, and the proposed integrated method is used to prioritize the failure modes.Originality/valueMamdani-type singleton IT2F inference model is employed in the FMEA. Additionally, the proposed model allows experts to construct their membership functions and fuzzy rules to capitalize on the experience and knowledge of the experts. The proposed group FMEA model aggregates experts' judgments by using IT2F-BWM and IT2F-WASPAS methods. The proposed model is implemented in a real-life case study in the furniture company.

Gear Tribology and Lubrication

2005 ◽  
pp. 19-38
Keyword(s):  
Film Thickness ◽  
Case History ◽  
Failure Modes ◽  
Gear Tooth ◽  
Lubricant Film ◽  
Flash Temperature ◽  
Lubricant Film Thickness ◽  
Film Lubrication

Abstract This chapter reviews the knowledge of the field of gear tribology and is intended for both gear designers and gear operators. Gear tooth failure modes are discussed with emphasis on lubrication-related failures. The chapter is concerned with gear tooth failures that are influenced by friction, lubrication, and wear. Equations for calculating lubricant film thickness, which determines whether the gears operate in the boundary, elastohydrodynamic, or full-film lubrication range, are given. Also, given is an equation for Blok's flash temperature, which is used for predicting the risk of scuffing. In addition, recommendations for lubricant selection, viscosity, and method of application are discussed. The chapter discusses in greater detail the applications of oil lubricant. Finally, a case history demonstrates how the tribological principles discussed in the chapter can be applied practically to avoid gear failure.

Fuzzy Hybrid FMEA for Risk Assessment in Service Industry

2021 ◽  
pp. 43-75
Author(s):  
Nihan Kabadayi
Keyword(s):  
Risk Assessment ◽  
Hospitality Industry ◽  
Failure Modes ◽  
Service Industry ◽  
Service Providers ◽  
Real Life ◽  
Potential Risks ◽  
Fmea Method ◽  
Organization Failure

Service products are mostly produced and consumed simultaneously through interaction between customer and service providers. To prevent external failures in service operations, it is important to identify potential risks and take relevant actions to eliminate or reduce the occurrence. Therefore, risk assessment is vital to customer satisfaction in any service organization. Failure mode and effects analysis (FMEA) is an effective and useful tool for risk assessment. Although FMEA has been extensively studied in the manufacturing literature, there are a limited number of studies considering the application of FMEA in the hospitality industry. In traditional FMEA, the risk priority of failure modes is determined by generating a crisp risk priority number (RPN). However, it has been claimed in the literature that crisp RPN doesn't have a good performance in reflecting real-life situations. To overcome this shortcoming, a fuzzy hybrid FMEA method is developed. The proposed method has been tested on a case study in a five-star hotel to assess its applicability and benefits.

Prediction of Traction in Sliding EHD Contacts

1976 ◽  
Vol 98 (3) ◽  
pp. 362-365 ◽  
Author(s):  
R. Kunz ◽  
W. O. Winer
Keyword(s):  
Shear Stress ◽  
Film Thickness ◽  
Surface Temperature ◽  
Material Properties ◽  
Rheological Model ◽  
Normal Load ◽  
Point Contact ◽  
Temperature Data ◽  
Stress Theory ◽  
Surface Temperature Data

An existing shear stress theory and lubricant rheological model were studied and evaluated by applying them to traction prediction in a sliding elastohydrodynamic point contact. Numerical calculations, using measured film thickness and surface temperature data, were compared with measured tractions under several conditions of normal load and sliding speed. In addition, the theory was used to study the effect on the traction of variations in the lubricant material properties.

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