1. OBJECTIVES
The objectives of the experiment are:
• Measurement of creep deformation in 2 materials; lead and polypropylene at room temperature.
• Determine how creep deformation of chosen materials can be affected by stress.
• Recognise that the two classes of materials show differences in creep behaviour.
• Awareness of creep as a design consideration.
2. THEORY
2.1 Introduction
Structural materials are often placed in service under a certain applied load at elevated temperatures (eg. wind turbines). Over time, the material elongates as a result of the strain accumulated and deforms. Such time-dependent deformation is dubbed as creep. Creep deformation can happen due to long-term exposure to high levels of stress, albeit still below the yield strength of the material. It usually happens at high temperature, but can also occur at room …show more content…
Calculate the tensile forces (Newtons) and the corresponding stresses for loads of 0.7 kg, 0.8 kg, and 0.9 kg.
3.2.1 Experiment 1 - Creep of Lead
1) Put the Lever Arm in place by using 2 pins; 1 pin to be inserted into the Bearing Block and the other to the Weight Holder (insert through the top hole).
2) Insert the other 2 pins to hold the specimen.
3) Insert the Dial Gauge into the hole (Do not tighten the nylon screw).
4) Using the Groove Plate insert the groove (or notch) into the top of the Dial Gauge, then secure it to the Lever Arm using the Thumb Nut.
5) Release the Rest Pin from the Weight Holder to take up any free movement.
6) Ensure that the specimen is in vertical position.
7) Gently lift up the Dial Gauge until the inner dial reads 3mm, then tighten the nylon screw.
8) Turn the outer ring of the Dial Gauge until the needle is at '0'.
9) Put the required weight (0.9 kg, 1.0 kg, or 1.1 kg) on the Weight Holder.
10) Raise the Weight Holder to the load position and insert the pin into the second hole (bottom
The objectives of the experiment are:
• Measurement of creep deformation in 2 materials; lead and polypropylene at room temperature.
• Determine how creep deformation of chosen materials can be affected by stress.
• Recognise that the two classes of materials show differences in creep behaviour.
• Awareness of creep as a design consideration.
2. THEORY
2.1 Introduction
Structural materials are often placed in service under a certain applied load at elevated temperatures (eg. wind turbines). Over time, the material elongates as a result of the strain accumulated and deforms. Such time-dependent deformation is dubbed as creep. Creep deformation can happen due to long-term exposure to high levels of stress, albeit still below the yield strength of the material. It usually happens at high temperature, but can also occur at room …show more content…
Calculate the tensile forces (Newtons) and the corresponding stresses for loads of 0.7 kg, 0.8 kg, and 0.9 kg.
3.2.1 Experiment 1 - Creep of Lead
1) Put the Lever Arm in place by using 2 pins; 1 pin to be inserted into the Bearing Block and the other to the Weight Holder (insert through the top hole).
2) Insert the other 2 pins to hold the specimen.
3) Insert the Dial Gauge into the hole (Do not tighten the nylon screw).
4) Using the Groove Plate insert the groove (or notch) into the top of the Dial Gauge, then secure it to the Lever Arm using the Thumb Nut.
5) Release the Rest Pin from the Weight Holder to take up any free movement.
6) Ensure that the specimen is in vertical position.
7) Gently lift up the Dial Gauge until the inner dial reads 3mm, then tighten the nylon screw.
8) Turn the outer ring of the Dial Gauge until the needle is at '0'.
9) Put the required weight (0.9 kg, 1.0 kg, or 1.1 kg) on the Weight Holder.
10) Raise the Weight Holder to the load position and insert the pin into the second hole (bottom