{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Tension Test - ME 220 MECHANICS OF MATERIALS LAB Tension...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
ME 220 - MECHANICS OF MATERIALS LAB Tension Test Test: September 13 th , 2007 Submitted: September 20 th , 2007 Matthew Olsen Section 3
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Background image of page 2
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Summary The purpose of the tension test is to determine the strength and inelastic properties of A36 steel and cast iron, and to observe the deformation and fracture behavior of these materials under extreme, slow tensile load. The properties that will be measured or calculated include the stress, strain, true stress, true strain, modules of toughness, elasticity, and resilience, ductility, yield strength, and ultimate strength. The strength of a material can be measured as the maximum tensile load it can hold before fracture. A material that is more ductile can hold more before fracture due to the property of elasticity. The ductile material will stretch much like a spring, even past the point of recovery to withstand the load. A brittle load may not behave similarly. It may be more likely to simply crack rather than deform. To test a material’s strength and measure its inelastic properties, a half inch “button-head” round bar will be placed in a tension machine, which will apply a slowly increasing axial load until the bar fractures. Two marks 2 inches apart are made on the bar, and the change in their distance is constantly measured throughout the test. A computer is setup to take data at intervals, recording the load and stretch length at each interval. From this data, all the above listed properties can be calculated, and the behavior of the material can be seen graphically. The following pages outline this information. When testing the A36 steel, the materials extreme ductility became apparent. The material stretched its length 35%, supporting a load of 14,350 pounds before fracturing. The cast iron did not deform any measureable amount, and held only 6,700 pounds. The fracture of the steel occurred only after stretching and necking, a visible process. The point of fracture demonstrated a perfect cup and cone fracture surface. The iron, however, simply cracked. When reassembled, the specimen looks identical to before the test. From these results, it can be seen that A36 is a ductile material, and cast iron is a brittle one.
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}