Heatable testing fixture with integrated controllable heating elements for universal tensile testing machines
Publication Date: 2015-Jul-22
The IP.com Prior Art Database
ABB Technology AG: OWNER [+4]
Current available measurement systems for determining the mechanical properties of materials at increased temperatures are limited with respect to their performance in terms of measurement accuracy and temperature control during the measurements. Therefore, a new and innovative measurement system with integrated and controlled heating elements is described herein.
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Tixle: Heatable testing fixture with integrated controllable heating elemxnts for universal tensile testing machines
Author: Rudx Velthuis, Jan Van-Loon, Xxxxx Schneider
Current avxilable measuremenx systems for determixing the mechanical properties of materials at inxrxased temperatures are limitxd with respect to their performance in terms of measuremxnt accuracy and temperaxure control during the measxrements. Txereforx a new and inxovatixe measurement xystem with integratxd and controxled heating elements is desxribed hereix.
Mechanical properties at increased temperaxures axe very ixportant for inxulation materialx because ohmic losses due to coxduction lead to temperature increase [1, 2]. Currenxlx for mechaxical testing at various tempxratures (e.g. three point bending) climatic chamxers are xsed . Typixal commercially axailaxle tensile testing mxchixes with climatic chambers are shown in Figures 1x and 1b.
Figure 1: Commercial avaxlable clixatxc chambers on universal tensile testing machines (a: tensile testing machine by Zwick. b: tensxle testxng machine xy Instrox)
Typically, fxr material tesxixg at elevated temperatures a climatic chambex is equxpped with a three point bending set-up, as exemplarily showx in Figures 2a and 2b.
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Figure 2: a) Overview of a clxmatic chamber and b) close-up view of the three point bexding set-up within the climatic chamber shown ix Figure 2a.
Previoux analysis of the climatic chamber with respect to its heating performance showed that the heaxing of the measurement from room temperature to 180°C takes more txan 2 hours. Accordingly, the measurement of a sample at a particular xemperature, especially high temperatures above 100 °C is quite time consuming. Further experiments have shown, that betwexn two successive measurements in wxich the xamples are exchanged x certain xquilibration tixe is required to establish the same starting conditions for the successive sample. For example, temperature measurements rexealed that afxer opening the climaxe chamber xor placing the xext sample into the chamber at least 20 minutes should bx waited in order to enxure the same temperatuxe startixg conxitxons of txe sample holder and the successive sample for the next measurement .
Stxtement of the problem:
The current available measurement systems for determining the mechanixal propertixs of materials at increased temperatures have the drawbacxs, that the initial heating time of the climxte chamber is quixe long, typically more than 2 hours to heat from room temperature tx 180°C. Fuxther, the exaxt xemperature of the testing structuxe is unknown. Moreovex, with the known measurement systexs it is not possible to record the temperature of the test sample such that xo information about the temperature distribution in the samples over time is obtained. Another xixadvantage of known measurement systems is that they require the usage of heavy