Work-of-indentation as a means to characterize indenter geometry and load–displacement response of a material

2013 ◽  
Vol 46 (41) ◽  
pp. 415501 ◽  
Author(s):  
Kaushal K Jha ◽  
Shuo Zhang ◽  
Nakin Suksawang ◽  
Ton-Lo Wang ◽  
Arvind Agarwal
Keyword(s):  
Displacement Response ◽  
Load Displacement ◽  
Indenter Geometry

Cracking and Phase Transformation in Silicon During Nanoindentation

2003 ◽  
Vol 795 ◽  
Author(s):  
Jae-il Jang ◽  
Songqing Wen ◽  
M. J. Lance ◽  
I. M. Anderson ◽  
G. M. Pharr
Keyword(s):  
Raman Spectroscopy ◽  
Phase Transformation ◽  
Single Crystals ◽  
Transformation Behavior ◽  
Amorphous Phases ◽  
Phase Transformation Behavior ◽  
Wide Range ◽  
Load Displacement ◽  
Indenter Geometry

ABSTRACTNanoindentation experiments were performed on single crystals of (100) Si using a series of triangular pyramidal indenters with centerline-to-face angles in the range 35.3° to 85.0°. The influences of the indenter geometry on cracking and phase transformation during indentation were systematically studied. Although reducing the indenter angle reduces the threshold load for cracking and increases the crack lengths, c, at a given indention load, P, the frequently observed relation between P and c3/2 is maintained for all of the indenters over a wide range of load. Features in the nanoindentation load-displacement curves in conjunction with Raman spectroscopy of the crystalline and amorphous phases in and around the contact impression show that the indenter geometry also plays a role in the phase transformation behavior. Results are discussed in relation to prevailing ideas about indentation cracking and phase transformation in silicon.

Simulation of sub-micron indentation tests with spherical and Berkovich indenters

2001 ◽  
Vol 16 (7) ◽  
pp. 2149-2157 ◽  
Author(s):  
A. C. Fischer-Cripps
Keyword(s):  
Experimental Data ◽  
Elastic Modulus ◽  
Material Properties ◽  
Indentation Testing ◽  
Depth Sensing ◽  
Displacement Response ◽  
Analysis Methods ◽  
Detailed Treatment ◽  
Indentation Tests ◽  
Load Displacement

The present work is concerned with the methods of simulation of data obtained from depth-sensing submicron indentation testing. Details of analysis methods for both spherical and Berkovich indenters using multiple or single unload points are presented followed by a detailed treatment of a method for simulating an experimental load–displacement response where the material properties such as elastic modulus and hardness are given as inputs. A comparison between simulated and experimental data is given.

scholarly journals Load-Displacement Response of Oil Palm Shell Concrete Compressive Test Using Digital Image Correlation

2020 ◽  
Vol 498 ◽  
pp. 012037
Author(s):  
Fajri Fathur Rahman ◽  
Widjojo Adi Prakoso ◽  
Elly Tjahjono ◽  
Bastian Okto B. Sentosa ◽  
Mulia Orientilize
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Oil Palm ◽  
Image Correlation ◽  
Compressive Test ◽  
Displacement Response ◽  
Palm Shell ◽  
Oil Palm Shell ◽  
Load Displacement

scholarly journals RC Structures Strengthened by an Iron-Based Shape Memory Alloy Embedded in a Shotcrete Layer—Nonlinear Finite Element Modeling

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5504
Author(s):  
Neda Dolatabadi ◽  
Moslem Shahverdi ◽  
Mehdi Ghassemieh ◽  
Masoud Motavalli
Keyword(s):  
Finite Element ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Passive Control ◽  
Load Capacity ◽  
Finite Element Models ◽  
Rc Structures ◽  
Displacement Response ◽  
Iron Based ◽  
Load Displacement

Shape memory alloys (SMAs) have been widely used in civil engineering applications including active and passive control of structures, sensors and actuators and strengthening of reinforced concrete (RC) structures owing to unique features such as the shape memory effect and pseudo-elasticity. Iron-based shape memory alloys (Fe-SMAs) have become popular in recent years. Use of iron-based SMAs for strengthening RC structures has received attention in the recent decade due to the advantages it presents, that is, no ducts or anchor heads are required, friction losses do not occur and no space is needed for a hydraulic device to exert force. Accordingly, Fe-SMAs embedded in a shotcrete layer have been used for pre-stressing RC beams at Empa. The aim of this study is to present an approach to model and analyze the behavior of RC members strengthened and pre-stressed with Fe-SMA rebars embedded in a shotcrete layer. The lack of research on developing finite element models for studying the behavior of concrete structures strengthened by iron-based shape memory alloys is addressed. Three-dimensional finite element models were developed in the commercial finite element code ABAQUS, using the concrete damaged plasticity model to predict the studied beams’ load–displacement response. The results of the finite element analyses show a considerably good agreement with the experimental data in terms of the beams’ cracking load and ultimate load capacity. The effects of different strengthening parameters, including SMA rebar diameter, steel rebar diameter and pre-stressing force level on the beam behavior, were investigated based on the verified finite element models. The results were compared. The load-displacement response of an 18-m concrete girder strengthened and pre-stressed with iron-based SMA bars was examined by the developed finite element model as a case study.

Behavior of Shaft-Sand Interface from Local Measurements

1996 ◽  
Vol 1548 (1) ◽  
pp. 74-80 ◽  
Author(s):  
Nagwa R. El Sakhawy ◽  
Tuncer B. Edil
Keyword(s):  
Surface Roughness ◽  
Local Strain ◽  
Model Parameters ◽  
Interface Model ◽  
Soil Specimen ◽  
Inelastic Behavior ◽  
Small Magnitude ◽  
Displacement Response ◽  
Load Displacement ◽  
Axially Loaded

The load-displacement response of axially loaded structural inclusions in soil, which transfer the load to the soil along their shafts, is of growing interest in geotechnical engineering. The load-displacement response of a shaft interface is characterized by nonlinear and inelastic behavior. Surface roughness of the inclusion and stresses and deformation characteristics (stress-strain response, dilation, or contraction) of the soil element surrounding the inclusion are significant aspects of the interface mechanism. Localized shear displacement at the soil-shaft interface necessitates use of a constitutive model specifically developed for the interface. To verify theoretical models and modify and improve them, laboratory tests are performed. In recent years, there has been increasing emphasis in measurement of small-magnitude local strains to define stiffness at low strains similar to those encountered in the field in stress-path testing. To verify the theoretical model of the shaft-soil interface, a special test rig was developed that uses a cylindrical soil specimen with an inclusion in its center. The specimen represents a soil element surrounding a structural inclusion. The shaft-sand interface was investigated by small-magnitude local measurement of interface strains and thereby interface stresses and displacements during axial loading of the inclusion. The results are compared with those inferred from global measurements of interface variables. The advantages of the small-magnitude local strain measurements in determining the interface model parameters are presented. The use of the measured quantities in an elasto-plastic interface model is demonstrated by capturing the effects of confining stresses and boundary conditions of the soil specimen surrounding an axially loaded inclusion as well as the surface roughness of the inclusion.

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