A hybrid method for determining material properties from instrumented micro-indentation experiments

1994 ◽  
Vol 9 (5) ◽  
pp. 1314-1321 ◽  
Author(s):  
Y-M. Chen ◽  
A.W. Ruff ◽  
J.W. Dally
Keyword(s):  
Penetration Depth ◽  
Material Properties ◽  
Ofhc Copper ◽  
Material Constants ◽  
Computation Process ◽  
Indentation Experiment ◽  
Micrometer Scale ◽  
The Impact ◽  
The Relationship ◽  
Micro Indentation

The impact code EPIC was employed to study the relationship between the applied force and the penetration depth in a micrometer-scale indentation experiment with oxygen free high conductivity (OFHC) copper. EPIC is an elastic-plastic finite element code that uses a Lagrangian formulation and triangular mesh, which can accommodate large deformation without the need to remesh during the computation process. By fitting the force-penetration curves for a triangular indenter with second degree polynomials, it was demonstrated that the fit changed with two material constants in the constitutive equation. A systematic procedure for determining the material constants is described that is based on matching either the slope or the curvature of the force penetration depth curves from numerical simulation and experiments. It is concluded that material constants can be determined from indentation data obtained using pyramidal or spherical indenters as well as a flat-ended indenter.

Study on Corner Contact Shock of Gear Transmission by ADAMS Software

2015 ◽  
Vol 778 ◽  
pp. 205-211
Author(s):  
Li He ◽  
Jin Yuan Tang
Keyword(s):  
Penetration Depth ◽  
Impact Velocity ◽  
Impact Force ◽  
Ansys Software ◽  
New Approach ◽  
Adams Software ◽  
Simulation Results ◽  
The Impact ◽  
The Relationship ◽  
Key Parameter

Solving gear meshing impact force problems by using ADAMS software is studied.A pair of tooth meshing model is established based on UG, modal neutral file is generated by using ANSYS software, calculating gear meshing impact after Importing ADAMS. The relationship between the impact velocity and the impact force by taking reasonable key parameter about penetration depth in ADAMS simulation.A new approach for studying gear meshing impact is proposed here, and the simulation results show that ADAMS software is a very useful tool for solving gear corner contact shock problems outside the normal path of action line.

Strength Estimates for High Velocity Penetration of Geological Targets by the Compaction Ring Theory

2004 ◽  
Author(s):  
D. Zach Nuckols ◽  
S. E. Jones
Keyword(s):  
Rigid Body ◽  
Penetration Depth ◽  
Material Properties ◽  
Target Material ◽  
Ring Theory ◽  
Cavity Expansion ◽  
Target Response ◽  
Penetration Process ◽  
Target Yield ◽  
The Impact

Existing theories for rigid body penetration model the target response to a penetration process as a cavity-expansion. A new analysis, however, offers an innovative approach to rigid body penetration of porous geological targets. The theory analyzes the formation of a compacted ring of target material observed around the boreholes in recovered targets. Applying fundamental laws of motion to an element during the formation of the ring leads to estimates for the three stresses that control the penetration event. A retarding force on the projectile nose is derived and then used to arrive at an estimate for penetration depth. The penetration depth equation, resulting from this model, is dependent upon known projectile properties, target material properties, and the impact velocity. Neglected are the effects of friction and shear. The solving procedure returns an estimate for the target yield strength. The model can then be used to predict the penetration of any penetrator into the target material. The results are promising and in agreement with the experimental observations.

scholarly journals Mathematical Model for Charpy Impact Energy of V-Notch Specimens

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Wei Wang ◽  
Ping Wang ◽  
Xuesong Liu ◽  
Zhibo Dong ◽  
Hongyuan Fang
Keyword(s):  
Mathematical Model ◽  
Impact Energy ◽  
Material Properties ◽  
Theoretical Basis ◽  
Impact Resistance ◽  
Charpy Impact ◽  
The Impact ◽  
The Mathematical Model ◽  
The Relationship ◽  
Derivation Process

Firstly, by analyzing the response of Charpy V-notch specimen impacted by pendulum, the relationship between specimen geometry, material properties, and impact energy is established and simplified, and the mathematical model for evaluating impact energy of specimens with different sizes is established. Then, the effectiveness of the model through a series of impact tests is verified. Theoretical analysis and experimental results show that the relationship between ligament length and impact energy is quadratic, while the relationship between ligament thickness and impact energy is linear. In the derivation process, the intrinsic impact toughness is used to evaluate the toughness of materials. The mathematical model makes it possible to evaluate the impact energy of specimens with different sizes and provides a theoretical basis for evaluating the impact resistance of structures.

Micro Abrasive Jet Machining of Silicon Carbide (SiC) Fiber Reinforced Ceramic Matrix Composite

2010 ◽  
Vol 126-128 ◽  
pp. 946-951 ◽  
Author(s):  
Ke Ju Chou ◽  
Hatsuhiko Usami ◽  
Kazuki Enomoto
Keyword(s):  
Silicon Carbide ◽  
Ceramic Composite ◽  
Ceramic Matrix Composite ◽  
Silicon Carbide Fiber ◽  
Fiber Reinforced ◽  
Sic Fiber ◽  
Abrasive Jet Machining ◽  
Indentation Experiment ◽  
The Impact ◽  
Micro Indentation

Abesive jet machining (AJM) of silicon carbide fiber reinforced silicon carbide ceramic composite (SiC/SiC CMC) was carried out with various size of silicon carbide fine abresives. A micro indentation experiment was connected to evaluate of maerial removal mechanism by the particle impact. Results showed that the machine rate was different depending on the particle size and that inteface fracture (debonding) has influenced on the material removal mechanim. Relationship between structure scale of the SiC/SiC CMC and the impact media size was discussed.

Study on the Influence of Painting Processes on the Protective Property of Concrete Coating

2012 ◽  
Vol 509 ◽  
pp. 88-92
Author(s):  
Yan Zheng ◽  
Qian Jin Mao ◽  
Ya Li Wang ◽  
Zi Ming Wang ◽  
Su Ping Cui
Keyword(s):  
Penetration Depth ◽  
Chloride Ion ◽  
Chloride Permeability ◽  
Acrylic Emulsion ◽  
Effective Measure ◽  
Water Based ◽  
Protective Performance ◽  
The Impact ◽  
The Relationship ◽  
Durability Of Concrete

With the development of construction project the durability of concrete is becoming more and more prominent, and surface coating is an effective measure to enhance the durability of concrete. Water-based silicone acrylic emulsion coating and water-based fluorocarbon resin coating were chose as prime and topcoat respectively. The impact of the coating’s thickness and viscosity on the durability of concrete and the relationship between the viscosity of the coating and its penetration depth were testified by chloride ion permeability-resistance property of concrete. The results show that thickness is proportional to the protective performance of the coating, and the penetration depth highly depends on viscosity. And the result of coating-4 viscosity method shows that samples with viscosity between 15 and 25 seconds have better chloride permeability resistance.

Material Property Identification and Sensitivity Analysis Using Micro-Indentation

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Long Ge ◽  
Nam H. Kim ◽  
Gerald R. Bourne ◽  
W. Gregory Sawyer
Keyword(s):  
Mechanical Properties ◽  
Sensitivity Analysis ◽  
Material Properties ◽  
Numerical Technique ◽  
Response Surfaces ◽  
Small Scale ◽  
Test Statistics ◽  
Indentation Experiment ◽  
The Difference ◽  
Micro Indentation

Mechanical properties of materials in small-scale applications, such as thin coatings, are often different from those of bulk materials due to the difference in the manufacturing process. Indentation has been a convenient tool to study the mechanical properties in such applications. In this paper, a numerical technique is proposed that can identify the mechanical properties using optimization and evaluate the robustness of identified material properties using sensitivity analysis. First, two response surfaces are constructed for loading and unloading curves from the indentation experiment of a gold film on the silicon substrate. Unessential coefficients of the response surface are then removed based on the test statistics. Unlike the traditional methods of identification, the tip geometry of the indenter is included because its uncertainty significantly affects the results. In order to validate the accuracy and stability of the method, the sensitivity of the identified material properties with respect to each coefficient is analyzed. It turns out that the plastic hardening parameter is the most sensitive to the experimental data. In addition, all material parameters are sensitive to the coefficients of higher-order bases. However, their effects are diminished because the magnitudes of these coefficients are small.

scholarly journals On the relationship between force reduction, loading rate and energy absorption in athletics tracks

2017 ◽  
Vol 232 (2) ◽  
pp. 71-78 ◽  
Author(s):  
Luca Andena ◽  
Antonio Ciancio ◽  
Francesco Briatico-Vangosa ◽  
Stefano Mariani ◽  
Andrea Pavan
Keyword(s):  
Material Properties ◽  
Loading Rate ◽  
Stored Energy ◽  
Compression Tests ◽  
Static Compression ◽  
Track Geometry ◽  
Force Reduction ◽  
The Impact ◽  
The Relationship ◽  
Quasi Static Compression

In this work, finite element simulations of typical sports surfaces were performed to evaluate parameters, such as the loading rate and the energy absorbed by the surface, in relation to its characteristics (surface structure and material properties). Hence, possible relations between these quantities and the standard parameters used to characterize the shock absorbing characteristics of the athletics track (in particular, its force reduction) were investigated. The samples selected for this study were two common athletics tracks and a sheet of natural rubber. They were first characterized by quasi-static compression tests; their mechanical properties were extrapolated to the strain rate of interest and their dependence on the level of deformation was modelled with hyperelastic constitutive equations. Numerical simulations were carried out for varying sample thicknesses to understand the influence of track geometry on force reduction, loading rate and stored energy. A very good correlation was found between force reduction and the other relevant parameters, with the exception of the loading rate at the beginning of the impact.

Accent Policy and Accent Modification Enterprises as Potential Indicators of Intercultural Power Relations: A Call for an Updated Research Agenda

2013 ◽  
Vol 3 (1) ◽  
pp. 22-33 ◽  
Author(s):  
Brynne D. Ovalle ◽  
Rahul Chakraborty
Keyword(s):  
International Relations ◽  
Identity Construction ◽  
Social Theory ◽  
Power Relations ◽  
Linguistic Diversity ◽  
Cultural Organization ◽  
Using Data ◽  
The Individual ◽  
The Impact ◽  
The Relationship

This article has two purposes: (a) to examine the relationship between intercultural power relations and the widespread practice of accent discrimination and (b) to underscore the ramifications of accent discrimination both for the individual and for global society as a whole. First, authors review social theory regarding language and group identity construction, and then go on to integrate more current studies linking accent bias to sociocultural variables. Authors discuss three examples of intercultural accent discrimination in order to illustrate how this link manifests itself in the broader context of international relations (i.e., how accent discrimination is generated in situations of unequal power) and, using a review of current research, assess the consequences of accent discrimination for the individual. Finally, the article highlights the impact that linguistic discrimination is having on linguistic diversity globally, partially using data from the United Nations Educational, Scientific and Cultural Organization (UNESCO) and partially by offering a potential context for interpreting the emergence of practices that seek to reduce or modify speaker accents.

Business: Making Cents of Coding Systems: Billing for Professional Services

2010 ◽  
Vol 20 (1) ◽  
pp. 3-8
Author(s):  
Dee Adams Nikjeh
Keyword(s):  
Professional Services ◽  
Speech Language Pathology ◽  
Coding Systems ◽  
Language Pathology ◽  
Program Funding ◽  
Fee Schedule ◽  
Procedure Codes ◽  
Relationship Of ◽  
The Impact ◽  
The Relationship

Abstract Administrators and supervisors face daily challenges over issues such as program funding, service fees, correct coding procedures, and the ever-changing healthcare regulations. Receiving equitable reimbursement for speech-language pathology and audiology services necessitates an understanding of federal coding and reimbursement systems. This tutorial provides information pertaining to two major healthcare coding systems and explains the relationship of these systems to clinical documentation, the Medicare Physician Fee Schedule and equitable reimbursement. An explanation of coding edits and coding modifiers is provided for use in those occasional atypical situations when the standard use of procedural coding may not be appropriate. Also included in this tutorial is a brief discussion of the impact that the Medicare Improvements for Patients and Providers Act of 2008 (HR 6331 Medicare Improvements for Patients and Providers Act [MIPPA], 2008) has had on the valuation of speech-language pathology procedure codes.

The Need to Belong and the Relationship Between Loneliness and Health

2014 ◽  
Vol 22 (4) ◽  
pp. 194-201 ◽  
Author(s):  
Freda-Marie Hartung ◽  
Britta Renner
Keyword(s):  
Individual Differences ◽  
Social Isolation ◽  
Social Situation ◽  
First Year ◽  
Health State ◽  
Need To Belong ◽  
First Year University ◽  
Perceived Social Isolation ◽  
The Impact ◽  
The Relationship

Humans are social animals; consequently, a lack of social ties affects individuals’ health negatively. However, the desire to belong differs between individuals, raising the question of whether individual differences in the need to belong moderate the impact of perceived social isolation on health. In the present study, 77 first-year university students rated their loneliness and health every 6 weeks for 18 weeks. Individual differences in the need to belong were found to moderate the relationship between loneliness and current health state. Specifically, lonely students with a high need to belong reported more days of illness than those with a low need to belong. In contrast, the strength of the need to belong had no effect on students who did not feel lonely. Thus, people who have a strong need to belong appear to suffer from loneliness and become ill more often, whereas people with a weak need to belong appear to stand loneliness better and are comparatively healthy. The study implies that social isolation does not impact all individuals identically; instead, the fit between the social situation and an individual’s need appears to be crucial for an individual’s functioning.

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