Single fibre mechanical properties play a critical role in determining sheet mechanical properties, but these mechanical properties are rarely measured due to the time-consuming nature of the tests. The zero span strength is commonly used as a measure for the strength of the fibres, but the results also can depend on the test conditions. Modelling has shown that the load displacement curves are influenced by the thickness to span ratio, as there is an in-homogenous stress-field in the thickness direction of the sample. This paper will present data on the effect of grammage and clamping pressure on the loads and displacements in zero/short span tests. Clamps were designed and made for a displacement controlled load frame made by Material Testing System (MTS). These clamps can test up to ten plies of papers with a span length from 0 to 3 mm. For the sake of comparison, tests were made using a commercial zero/short span tester, which is load controlled but is limited in span length and thickness of the tested material. Both machines were found to give comparable results. Isotropic 65 gsm handsheets, 36 gsm aluminium foil and 42 gsm greaseproof paper (MD and CD) were tested as functions of clamping pressure and grammage. An intrinsic zero-span strength was defined as the y-axis intercept of plot. A recently published procedure for determining the short span stress-strain curve from zero and short span testing was evaluated for the effect of grammage, clamping pressure and span on the calculated result. It was concluded that the method only gives results that are independent of the test conditions when the conditions are carefully selected.
|Number of pages||6|
|Publication status||Published - 20 Nov 2003|
|Event||International Paper Physics Conference 2003 - Victoria, BC, Canada|
Duration: 7 Sep 2003 → 11 Sep 2003
|Conference||International Paper Physics Conference 2003|
|Abbreviated title||PAPTAC 2003|
|Period||7/09/03 → 11/09/03|