An Evaluation of Compression Testing Techniques of Sheet Materials at Elevated Temperatures

This article demonstrates the difference in the flow curves of an AZ31 magnesium alloy and S235JR structural steel wire caused by non-linear strain rates during uniaxial tensile and compression testing at elevated temperatures. Throughout tensile deformation, the traverse velocity of the testing machine has to be adapted according to the current elongation of the specimen, thus accelerating, to ensure a constant strain rate during the admission of the stress-strain curve. The equivalent is necessary during compression testing, where the traverse velocity of the testing machine needs to decelerate ensuring a constant strain rate. Nevertheless, tensile and compression tests are performed with constant traverse velocity, which lead to divergent flow curves in comparison to deformation controlled traverse velocities. The results of the research show the difference in flow behaviour of magnesium and steel wire, when the temperature and strain rate are varied in conjunction with constant and deformation controlled traverse velocities.

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Creep Assessment of Large Size High Temperature Components Using Small Creep Test Specimens

Volume 1: Operations and Maintenance, Aging Management and Plant Upgrades; Nuclear Fuel, Fuel Cycle, Reactor Physics and Transport Theory; Plant Systems, Structures, Components and Materials; I&C, Digital Controls, and Influence of Human Factors ◽

10.1115/icone24-60010 ◽

2016 ◽

Author(s):

Balhassn S. M. Ali

Keyword(s):

High Temperature ◽

Creep Test ◽

Nuclear Power ◽

Power Plants ◽

Elevated Temperatures ◽

Life Time ◽

Safe Operation ◽

Large Size ◽

Testing Techniques ◽

High Temperature Components

Most of the large components in the thermal, traditional and nuclear power plants such as pressurized vessels and pipes are operating at elevated temperatures. These temperatures and stress are high enough for creep to occur. For variety of reasons many of these power plants are now operating beyond their design life time. It is -known fact that as the high temperature components aged the failure rate normally increases as a result of their time dependent material damage. Further running of these components may become un-safe and dangerous in some cases. Therefore, creep assessment of the high temperature components of these plants is essential for their safe operation. Mainly for economic reasons these components have to be creep assessed as they are in service. However, assessing the creep strength for these high temperature components as they are in service, it can be challenging task, especially when these components are operating under extremely high temperature and/or stress. This paper introduces newly invented, small creep test specimens techniques. These new small types of specimens can be used to assess the remaining life times for the high temperature components, using only small material samples. These small material samples can be removed from the operating components surface, without affecting their safe operation. Two of the high temperature materials are used to validate the new testing techniques.

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Symposium on Elevated-Temperature Compression Testing of Sheet Materials

10.1520/stp303-eb ◽

1962 ◽

Author(s):

Ralph Papirno ◽

George Gerard

Keyword(s):

Elevated Temperature ◽

Compression Testing ◽

Sheet Materials

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A Fixture for Testing Sheet Materials in Compression at Elevated Temperatures

Journal of the Royal Aeronautical Society ◽

10.1017/s0001924000126491 ◽

1956 ◽

Vol 60 (550) ◽

pp. 669-674

Author(s):

D. C. Hayward

Keyword(s):

Compressive Stress ◽

Elevated Temperatures ◽

Design Study ◽

Stress Strain ◽

Sheet Materials ◽

Strength And Stiffness ◽

Loss Of Strength

SummarySupersonic speeds of flight have brought thermal problems due to the kinetic heating of skin materials. These materials, generally metallic, suffer loss of strength and stiffness with increase in temperature and a knowledge of changes in value of these properties at elevated temperatures is a pre-requisite to a design study. More particularly for stress offices the compressive stress-strain curves are required from which are derived tangent- and secant-moduli used to predict buckling in components. A fixture has therefore been developed for testing under edgewise compression sheet materials up to temperatures of 400 °C.

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