scholarly journals Time-Resolved Force Measurements to Determine Positioning Tolerances for Impulse-Based Indentations

2021 ◽  
Author(s):  
Tobias Valentino ◽  
Marian Höhmann ◽  
Kevin Schünemann ◽  
Jonas Wentzler ◽  
Tim Wünderlich ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Material Properties ◽  
Applied Load ◽  
Force Measurement ◽  
Vertical Displacement ◽  
Substrate Material ◽  
Spherical Indenter ◽  
Angle Of Incidence ◽  
Time Resolved ◽  
Indentation Force

AbstractHigh-throughput experimentation methods determine characteristic values, which are correlated with material properties by means of mathematical models. Here, an indentation method based on laser-induced shock waves is presented, which predicts the material properties, such as hardness and tensile strength, by the induced plastic deformation in the substrate material. The shock wave pushes a spherical indenter inside a substrate material. For reproducible indentations, the applied load is of importance. To compare different processes and process parameters, the measured plastic deformation is normalized by the applied load. However, eccentric irradiation leads to altered beam profiles on the surface of spherical indenters and the angle of incidence is changed. Thus, the influence of eccentric irradiation is studied with an adapted time-resolved force measurement setup to determine the required positioning tolerances. The spherical indenter is placed inside a cylindrical pressure cell to increase the laser-induced shock pressure. From the validated time-resolved force measurement method we derive that deviations from the indentation forces are acceptable, when the lateral deviation of the beam center, which depends only on the alignment of the setup, does not exceed ± 0.4 mm. A vertical displacement from the focus position between -3.0 mm and + 2.0 mm still leads to acceptable deviations from the indentation force.

scholarly journals Plastic deformation simulation of steel panels

2019 ◽  
Vol 29 ◽  
pp. 02012
Author(s):  
Mihaela Savin ◽  
Adrian Presura ◽  
Ionel Chirica
Keyword(s):  
Plastic Deformation ◽  
Numerical Simulations ◽  
Fem Analysis ◽  
Vertical Displacement ◽  
Displacement Transducer ◽  
Force Transducer ◽  
Spherical Indenter ◽  
Steel Panel ◽  
Experimental Stand ◽  
Steel Panels

This paper presents the FEM analysis of plastic deformation of different steel panels using a spherical indenter. Two experiments were done: first on a simple steel panel and second on a stiffened steel panel, which were subjected to a static plastic deformation produced with help of a spherical indenter. The results of the practical test were compared with the results of numerical simulations, which were accomplished using ANSYS-Static Structural module. The tests were realized using an experimental stand based on a screw press mechanism. The tests consist in vertical displacement of the spherical bulb, which in this way deformed the panel leaning on the stand frame. During the tests were measured the force applied to the indenter, with help of an PLC500 force transducer, and the vertical displacement of the panel in the application point of force, with help of an HBM WA/300 displacement transducer. The results of calculations are presented below as: final deformed models and force-displacement diagrams with the comparison between experiment and numerical simulation. In conclusion of this research the compared results between the experiments and numerical simulations revealed that can be achieved accurate results using FEM analysis for plastic deformation problems, with proper parameters settings.

Electron Channeling Patterns

1977 ◽  
Vol 35 ◽  
pp. 12-13
Author(s):  
David C. Joy
Keyword(s):  
Electron Diffraction ◽  
Incidence Angle ◽  
Photographic Plate ◽  
Diffraction Effect ◽  
Angle Of Incidence ◽  
Bulk Single Crystal ◽  
Time Resolved ◽  
Electron Channeling ◽  
Spatially Resolved ◽  
Large Bulk

Electron channeling patterns (ECP) were first found by Coates (1967) while observing a large bulk, single crystal of silicon in a scanning electron microscope. The geometric pattern visible was shown to be produced as a result of the changes in the angle of incidence, between the beam and the specimen surface normal, which occur when the sample is examined at low magnification (Booker, Shaw, Whelan and Hirsch 1967).A conventional electron diffraction pattern consists of an angularly resolved intensity distribution in space which may be directly viewed on a fluorescent screen or recorded on a photographic plate. An ECP, on the other hand, is produced as the result of changes in the signal collected by a suitable electron detector as the incidence angle is varied. If an integrating detector is used, or if the beam traverses the surface at a fixed angle, then no channeling contrast will be observed. The ECP is thus a time resolved electron diffraction effect. It can therefore be related to spatially resolved diffraction phenomena by an application of the concepts of reciprocity (Cowley 1969).

Determination of Charge Coefficient of Piezoelectric Films Using a Combined Finite Element Model and Dynamic Loading Technique

2020 ◽  
Vol 835 ◽  
pp. 229-242
Author(s):  
Oboso P. Bernard ◽  
Nagih M. Shaalan ◽  
Mohab Hossam ◽  
Mohsen A. Hassan
Keyword(s):  
Finite Element ◽  
Dynamic Loading ◽  
Material Properties ◽  
Accurate Determination ◽  
Substrate Material ◽  
Experimental Results ◽  
Piezoelectric Composite ◽  
Piezoelectric Film ◽  
Piezoelectric Charge

Accurate determination of piezoelectric properties such as piezoelectric charge coefficients (d33) is an essential step in the design process of sensors and actuators using piezoelectric effect. In this study, a cost-effective and accurate method based on dynamic loading technique was proposed to determine the piezoelectric charge coefficient d33. Finite element analysis (FEA) model was developed in order to estimate d33 and validate the obtained values with experimental results. The experiment was conducted on a piezoelectric disc with a known d33 value. The effect of measuring boundary conditions, substrate material properties and specimen geometry on measured d33 value were conducted. The experimental results reveal that the determined d33 coefficient by this technique is accurate as it falls within the manufactures tolerance specifications of PZT-5A piezoelectric film d33. Further, obtained simulation results on fibre reinforced and particle reinforced piezoelectric composite were found to be similar to those that have been obtained using more advanced techniques. FE-results showed that the measured d33 coefficients depend on measuring boundary condition, piezoelectric film thickness, and substrate material properties. This method was proved to be suitable for determination of d33 coefficient effectively for piezoelectric samples of any arbitrary geometry without compromising on the accuracy of measured d33.

scholarly journals Initial stages of yield in nanoindentation

1999 ◽  
Vol 14 (6) ◽  
pp. 2219-2227 ◽  
Author(s):  
J. D. Kiely ◽  
K. F. Jarausch ◽  
J. E. Houston ◽  
P. E. Russell
Keyword(s):  
Plastic Deformation ◽  
Plastic Zone ◽  
Applied Load ◽  
Elastic Behavior ◽  
Load Relaxation ◽  
Crystal Surfaces ◽  
Small Deviations ◽  
Single Crystal Surfaces ◽  
Complete Relaxation ◽  
Interfacial Force

We have used the interfacial force microscope to perform nanoindentations on Au single-crystal surfaces. We have observed two distinct regimes of plastic deformation, which are distinguished by the magnitude of discontinuities in load relaxation. At lower stresses, relaxation occurs in small deviations from elastic behavior, while at the higher stresses they take the form of large load drops, often resulting in complete relaxation of the applied load. These major events create a relatively wide plastic zone that subsequently deepens more rapidly than it widens. We discuss these findings in terms of contrasting models of dislocation processes in the two regimes.

scholarly journals Evaluation of thin, flexible sensors for time-resolved grip force measurement

2007 ◽  
Vol 221 (12) ◽  
pp. 1687-1699 ◽  
Author(s):  
E R Komi ◽  
J R Roberts ◽  
S J Rothberg
Keyword(s):  
Shear Force ◽  
Grip Force ◽  
Force Measurement ◽  
Real Life ◽  
Force Sensor ◽  
Ease Of Use ◽  
Time Resolved ◽  
Flexible Sensors ◽  
Sensor Performance ◽  
Dynamic Accuracy

Three types of thin, flexible force sensor were studied under a variety of loading conditions to determine their suitability for measuring grip force. Static accuracy, hysteresis, repeatability, and drift errors were established, the effects of shear force and surface curvature were considered, and dynamic accuracy and drift were measured. Novel tests were developed to consider dynamic accuracy and sensitivity to shear loadings. Additionally, three sensors were evaluated in a real-life gripping scenario, measuring grip force during a golf shot. Comments are made on sensor performance, ease of use, and durability.

Sensitivity of Modeling Parameters in Proximal Femur Analyses

2000 ◽  
Author(s):  
Eric L. Wang ◽  
Yanyao Jiang ◽  
Lixia Fan ◽  
Brian Greer
Keyword(s):  
Hip Fracture ◽  
Proximal Femur ◽  
Material Properties ◽  
Applied Load ◽  
Loading Rate ◽  
Frictional Resistance ◽  
Fracture Load ◽  
Loading Direction ◽  
Structural Capacity ◽  
Femoral Geometry

Abstract Hip fracture risk can be quantified using a factor of risk (Hayes et al., 1996): (1) Φ = Applied load / Fracture load The structural capacity, the denominator, can be affected by many parameters including femoral geometry, material properties, load locations, loading direction, loading rate, and frictional resistance.

Response of a vertical strain seismometer to body waves

1966 ◽  
Vol 56 (4) ◽  
pp. 785-791
Author(s):  
Indra N. Gupta
Keyword(s):  
Finite Length ◽  
Finite Depth ◽  
Vertical Displacement ◽  
Infinite Medium ◽  
Body Waves ◽  
Poisson's Ratio ◽  
Angle Of Incidence ◽  
Arbitrary Angle ◽  
Vertical Strain ◽  
Phase Relationships

abstract Expressions have been derived for vertical strain due to P and SV type waves arriving at an arbitrary angle of incidence within a semi-infinite medium. The amplitude and phase relationships between vertical strain and vertical displacement have been investigated for both wave types, assuming a Poisson's ratio of 0.25. The effect of finite depth and finite length of the vertical strain instrument has been examined and found to be significant especially for small angles of incidence.

Relaxation Processes in Ti-Al Composite Material after Rolling

2018 ◽  
Vol 284 ◽  
pp. 392-396
Author(s):  
D.N. Gurulev ◽  
L.V. Palatkina
Keyword(s):  
Plastic Deformation ◽  
Composite Material ◽  
Metal Forming ◽  
Body Shape ◽  
Applied Load ◽  
Relaxation Processes ◽  
Return To Equilibrium ◽  
Subtle Change ◽  
Al Composite ◽  
Flow Of Time

In the result of application of the load in different sections of the structure elastic or plastic deformation may occur. In its turn, the removal of the applied load can lead to the development of relaxation processes, caused by the intention of the material to return to equilibrium. There is a subtle change of body shape (warping), which depends on its properties, the type of deformation and its nature in the flow of time. In this regard, the consideration of this factor is necessary in the manufacture of various parts and components of LCM using the methods of metal forming (stamping, bending, calibration, etc.) [1-6].

scholarly journals Developing Nanostructured Ti Alloys for Innovative Implantable Medical Devices

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 967
Author(s):  
Ruslan Z. Valiev ◽  
Egor A. Prokofiev ◽  
Nikita A. Kazarinov ◽  
Georgy I. Raab ◽  
Timur B. Minasov ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Medical Devices ◽  
Material Properties ◽  
Medical Industry ◽  
Implantable Medical Devices ◽  
Fine Grained ◽  
Ti Alloys ◽  
Novel Approaches ◽  
Improved Design ◽  
Increased Strength

Recent years have witnessed much progress in medical device manufacturing and the needs of the medical industry urges modern nanomaterials science to develop novel approaches for improving the properties of existing biomaterials. One of the ways to enhance the material properties is their nanostructuring by using severe plastic deformation (SPD) techniques. For medical devices, such properties include increased strength and fatigue life, and this determines nanostructured Ti and Ti alloys to be an excellent choice for the engineering of implants with improved design for orthopedics and dentistry. Various reported studies conducted in this field enable the fabrication of medical devices with enhanced functionality. This paper reviews recent development in the field of nanostructured Ti-based materials and provides examples of the use of ultra-fine grained Ti alloys in medicine.

Sign in / Sign up

Export Citation Format

Share Document