Application of full-field measurements and numerical simulations to analyze the thermo-mechanical response of a three-branch rubber specimen

2011 ◽  
pp. 45-50 ◽  
Author(s):  
CX Balandraud ◽  
E Toussaint ◽  
J Le Cam ◽  
M Grédiac ◽  
R Behnke ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Mechanical Response ◽  
Field Measurements ◽  
Full Field ◽  
Rubber Specimen

scholarly journals A numerical investigation on impulse-induced nonlinear longitudinal waves in pantographic beams

2021 ◽  
pp. 108128652110108
Author(s):  
Emilio Turco ◽  
Emilio Barchiesi ◽  
Francesco dell’Isola
Keyword(s):  
Numerical Simulations ◽  
Mechanical Response ◽  
Integration Scheme ◽  
Present Contribution ◽  
Longitudinal Waves ◽  
Deformation Regime ◽  
Impulsive Loads ◽  
Unit Cells ◽  
Statics And Dynamics ◽  
Equations Of Motions

This contribution presents the results of a campaign of numerical simulations aimed at better understanding the propagation of longitudinal waves in pantographic beams within the large-deformation regime. Initially, we recall the key features of a Lagrangian discrete spring model, which was introduced in previous works and that was tested extensively as capable of accurately forecasting the mechanical response of structures based on the pantographic motif, both in statics and dynamics. Successively, a stepwise integration scheme used to solve equations of motions is briefly discussed. The key content of the present contribution concerns the thorough presentation of some selected numerical simulations, which focus in particular on the propagation of stretch profiles induced by impulsive loads. The study takes into account different tests, by varying the number of unit cells, i.e., the total length of the system, spring stiffnesses, the shape of the impulse, as well as its properties such as duration and peak amplitude, and boundary conditions. Some conjectures about the form of traveling waves are formulated, to be confirmed by both further numerical simulations and analytical investigations.

Improved infrared temperature mapping of elastohydrodynamic contacts

2009 ◽  
Vol 223 (8) ◽  
pp. 1165-1177 ◽  
Author(s):  
T Reddyhoff ◽  
H A Spikes ◽  
A V Olver
Keyword(s):  
Effective Means ◽  
Field Measurements ◽  
Operating Conditions ◽  
Mapping Technique ◽  
Shear Stresses ◽  
Measured Temperature ◽  
Ir Camera ◽  
Full Field ◽  
Group I ◽  
Increased Sensitivity

An effective means of studying lubricant rheology within elastohydrodynamic contacts is by detailed mapping of the temperature of the fluid and the bounding surfaces within the lubricated contact area. In the current work, the experimental approach initially developed by Sanborn and Winer and then by Spikes et al., has been advanced to include a high specification infrared (IR) camera and microscope. Besides the instantaneous capture of full field measurements, this has the advantage of increased sensitivity and higher spatial resolution than previous systems used. The increased sensitivity enables a much larger range of testable operating conditions: namely lower loads, speeds, and reduced sliding. In addition, the range of test lubricants can be extended beyond high shearing traction fluids. These new possibilities have been used to investigate and compare the rheological properties of a range of lubricants: namely a group I and group II mineral oil, a polyalphaolephin (group IV), the traction fluid Santotrac 50, and 5P4E, a five-ring polyphenyl-ether. As expected, contact temperatures increased with lubricant refinement, for the mineral base oils tested. Using moving heat source theory, the measured temperature distributions were converted into maps showing rate of heat input into each surface, from which shear stresses were calculated. The technique could therefore be validated by integrating these shear stress maps, and comparing them with traction values obtained by direct measurement. Generally there was good agreement between the two approaches, with the only significant differences occurring for 5P4E, where the traction that was deduced from the temperature over-predicted the traction by roughly 15 per cent. Of the lubricants tested, Santotrac 50 showed the highest average traction over the contact; however, 5P4E showed the highest maximum traction. This observation is only possible using the IR mapping technique, and is obscured when measuring the traction directly. Both techniques showed the effect of shear heating causing a reduction in traction.

The Effect of Uniaxial Cyclic Deformation on the Evolution of Phase Transformation Fronts in Pseudoelastic NiTi Wire

2001 ◽  
Author(s):  
Mark A. Iadicola ◽  
John A. Shaw
Keyword(s):  
Mechanical Response ◽  
Infrared Imaging ◽  
Partial Transformation ◽  
Niti Wire ◽  
Full Field ◽  
Temperature Experiment ◽  
Background Temperature ◽  
Higher Temperature ◽  
Lower Temperature ◽  
Niti Wires

Abstract Experiments are presented of the response of pseudoelastic NiTi wires subjected to displacement controlled cycles. A custom built thermo-mechanical testing apparatus is used to control the background temperature field of the wire specimen while allowing the evolution of transformation fronts to be tracked by full field infrared imaging. Two experiments under similar end-displacement histories, but at temperatures ≈8°C apart, are shown to give remarkably different cyclic responses. The mechanical response for the lower temperature experiment continued to soften but retained its shape through 43 partial transformation cycles, and the pattern of transformation fronts seemed to reach a steady state. The response for the higher temperature experiment showed a change in shape of the mechanical response and distinct changes in transformation front patterns over 31 partial transformation cycles.

In-situ Full Field Measurements During Inter-Facial Debonding in Single Fiber Composite Under Transverse Load

2018 ◽  
Vol 58 (9) ◽  
pp. 1451-1467 ◽  
Author(s):  
I. Tabiai ◽  
R. Delorme ◽  
D. Therriault ◽  
M. Levesque
Keyword(s):  
Fiber Composite ◽  
Field Measurements ◽  
Single Fiber ◽  
Transverse Load ◽  
Full Field
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