Database: A novel image-based ultrasonic test to map material mechanical properties at high strain rates
Authors: R. SEGHIR and F. PIERRON
Institution: University of Southampton
Date: 01/05/2016 - 01/08/2017

Abstract:
An innovative identification strategy based on high power ultrasonic loading together with both infrared thermography and ultra-high speed imaging is presented in this article. It was shown to be able to characterize the viscoelastic behaviour of a polymer specimen (PMMA) from a single sample over a wide range of temperatures and strain rates. The main originality lies in the fact that contrary to conventional DMT Analysis, no frequency or temperature sweep is required since the experiment is designed to simultaneously produce both a heteroge- neous strain-rate state and a heterogeneous temperature state allowing a local and multi-parametric identification. This article is seminal in nature and the test presented here has good potential to tackle a range of other types identify the high strain rate properties of materials, as of high strain-rate testing situations


The following file describe the database embedded within this directory.

Two test series has been performed:

	Experimental data corresponding to the first test series (low displacement amplitude) are in the directory "series1".
	- "UHS_data.mat" embeds post-treated kinematic data
	- "IR_data.mat" embeds post-treated thermal data
	- the directory "Grid_run6" provides grid images
corresponding to the run number 6

	Experimental data corresponding to the second test series (high displacement amplitude) are in the directory "series2".
 	- "UHS_data.mat" embeds post-treated kinematic data
 	- "IR_data.mat" embeds post-treated thermal data
 	- the directory "Grid_run5" provides grid images corresponding to the run number 5
 
	Thermo-coupled data are embedded in "ThermoCoupled_Data.mat". Data are here in vector mode, i.e. values along the sample length are concatenate over the time. The variable “Tri” allow extracting a specific ultrasonic run (i.e. data over sample length for a specimen ultrasonic run).


the variables are named as follows:

	- A.x : acceleration along x axis
 	- A.x_Harm : harmonic acceleration along x axis
	- S.xx : stress along x axis
 	- S.x_Harm : harmonic stress along x axis	
	- E.xx : strain along x axis
 	- E.dxx : strain-rate along the x axis	
	- E.GradExx : strain gradient along x axis
 	- U.xb : smoothed displacement along x axis	
	- U.xb : smoothed displacement along y axis	
 	- storageMod.sf : identified storage modulus	
 	- storageMod.sfH : identified storage modulus from harmonic assumptions
	- tandeltaMod.sf : identified damping	
 	- tandeltaMod.sfH : identified damping from harmonic assumptions
 	- coor.X and coor.Y : x and y positions	
 	- coor.time : timeline
	- coor.dimX, coor.dimY, coor.dimT and coor.dimID : number of datapoint along x, y and time axis and number of runs
	
	- The variable param is a structure which embeds all the experimental and numerical parameters


Simulation directory embeds results from harmonic, isotropic, homogeneous, purely elastic FE simulation done in Ansys 16.2. Post-treated data resulting from the same post-processing pipeline 
than for experimental data are embedded in "PostTreated_data.mat".