tension of metals

tension of metals - TENSION TEST OF METALS Robert J....

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

View Full Document Right Arrow Icon
TENSION TEST OF METALS Robert J. Lichtenthal III Jason Hutchinson Matthew Robbins February 2, 2007 Abstract: This lab experiment used a tensile strength testing machine to analyze various characteristics of three metal samples: steel, brass and aluminum. Through the data collected and computed, it was possible to determine the specific type of metals tested, which will be seen below. After recording data with data acquisition software, properties such as yield strength, modulus of elasticity, and rupture points were calculated. When comparing the three samples, it was obvious that steel was the strongest and least brittle material, brass was the most brittle material, and aluminum was the weakest of the materials. Graphs below will analyze these findings in greater detail along with the methods used to calculate these properties. It was also evident that the experiment was wrought with error. Potential sources and reasons for this error are described and accounted for below.
Background image of page 1

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

View Full DocumentRight Arrow Icon
Task One: Convert load data into stress data in metric units [N/m²] The raw data collected during the lab was expressed in various units, both English and Metric, which needed to be converted into standard units before analysis could begin. Conversion values used included: 1cm = 0.01 m 1mm = 0.001 m 1 inch = 2.54 cm 1 pound-foot = 4.448 N Once the raw data was converted into meters and Newtons using MATLAB [1], the initial cross-sectional area of the three samples were calculated and are shown in Table 1.1 below. Table 1.1 Initial Thickness (m) Initial Width (m) *Initial Area (m²) Steel 0.0016 0.0042 6.720 E -6 Aluminum 0.00165 0.0043 7.095 E -6 Brass 0.0016 0.0046 7.360 E -6 *Initial Area = Initial Thickness * Initial Width MATLAB [1] was then used to calculate stress from the load data expressed in Newtons, and the initial area expressed in squared meters. Stress = Force (load data) / Initial Area Stress data, expressed in N/m², was now ready for further analysis.
Background image of page 2
Task Two: Convert Position Data to Strain Data The data acquisition software, Lab View [2], recorded position data that also needed to be converted into standard units using the same conversion factors as Task One. The initial lengths of the three samples were measured with vernier calipers, and the values can be seen below in Table 2.1. Table 2.1 Gauge Length, LO, (m) Steel 0.01415 Aluminum 0.0157 Brass 0.01445 MATLAB [1] was used to calculate the deflection which is defined as: Deflection = Δ Length The sheer number of deflection values restricts their inclusion in this report. With MATLAB [1], it was possible to calculate strain data from the initial gauge lengths and the deflection data according to: Strain = Δ Length / LO The output of this function, strain, was saved as a matrix in MATLAB [1] just as the stress data was saved in Task One.
Background image of page 3

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

View Full DocumentRight Arrow Icon
Task Three: Plot Stress versus Strain With stress and strain data converted and calculated in the previous two tasks, the data is ready to be graphed and analyzed. The graphs for the three specimens can be seen
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.

Page1 / 15

tension of metals - TENSION TEST OF METALS Robert J....

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online