Tensile energy absorption

Folding endurance under tension (10) is a favorite physical property for research on paper permanence and is the basis for the TAPPI method (16). Application of the mechanism involved in this test procedure, however, is unknown in practical uses for paper. Comparisons among product choices and estimates of their useful life should be based upon tests that assess physical properties of practical interest. Retention of reflective brightness, tear strength, tensile energy absorption, and... 

TAPPI Suggested Method T-494su-64, Tensile Energy Absorption of... 

Tear and tensile energy absorption usually increased, and these properties are important to the handling properties of paper. 

In this case, the paper machine manufactures flat sack kraft paper from a blend of virgin pine (long-fibre) kraft pulp with typical Kappa range of 55-65 and eucalyptus (short-fibre) neutral sulfite semi-chemical (NSSC) pulp. The most important properties for sack papers are stretch and tensile energy absorption (TEA) in both cross direction (CD) and machine direction (MD). The major problems with the quality of sack papers currently made on this machine were poor stretch and TEA profile in fhe cross direction as shown in... 

Not only the strength properties, tensile strength and strain to rupture can be determined in the tensile strength test (ISO 1924, 1992), but also the tensile energy absorption, TEA, which is especially important for bag paper. The TEA value represents the nonelastic portion of the deformation energy and thus that portion of dissipated energy which should be high in the case of bag paper. 

Subsequently, the specimens are removed from the oven and should be tested after 24 hours. The tests selected should relate to a property relevant to actual service application, and standardized test methods should be utilized in order to allow for comparisons. If a specific application has not been defined, it is recommended to utilize a slow (tensile strength) and a rapid (impact tensile strength) tensile loading or electric loading (dielectric strength), respectively. ISO 11403-3 [103] lists tensile strength and/or tensile energy absorption as criteria. 

The polyurethane formulation Involved a proprietary crossllnkable system based on poly(propylene glycol) and methylene dllsocyanate (NCO/OH ratio = 1.0). For studies of viscoelastic, energy absorption, and fatigue behavior, the weight fractions of PUMA were 0, 0.25, 0.50, 0.75, and 1.0 for studies of tensile and tear strength, the ratios were 0, 0.10, 0.20, 0.25, 0.30, and 0.40. Reactants were mixed at room temperature, degassed, poured Into a mold, and cured at 60 C for 48 hr. 

Since the environmental history of the book would influence the results obtained from physical property measurements made on the paper, each book was preconditioned in a standard atmosphere (4) before any paper samples were removed. The following physical property measurements were made on the same pages throughout each of the control and dried books tensile breaking strength (5) tensile energy of absorption (6, 7) internal tear resistance (8) thickness (9) and hot-water extract-able acidity or alkalinity (10). 

Select low-temperature steels for fracture-critical structural members designed for tensile stress levels greater than a ksl (40 MPa) and specify a minimum Charpy V notch Impact energy absorption of 20 ft-lb (27 J) for base metal, heat-affected zones (HAZs), and welds when the structures are exposed to low-ambient temperatures. Fracture-critical members are those tension members whose failure would have a significant economic impact. 

Thus at a given rate the lowest rubber content which can induce ductility and suppress spallation will result in maximum energy absorption under impact. If this yield-spall transition coincides with the ductile-brittle transition which occurs in these tensile tests, the effective strain rate of the onset of spallation could be predicted by tests of this type. This ductile-brittle transition occurs at low effective strain rates for the unmodified material since it is brittle through the range of conditions used in these tests. For the 4% material at the highest effective strain rates achieved in these tests, the load maximum is just beginning to disappear. Thus, if rate-temperature equivalence holds, extension of these test to... 

Reiterer A, Lichtenegger H, Fratzl P and Stanzl-Tschegg SE (2001) Deformation and energy absorption of wood cell walls with different nanostructure under tensile loading. Journal of Materials Science, 35 4681-6... 

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