MET 211 Lab report 9

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Purdue University *

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21100

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Mechanical Engineering

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Apr 3, 2024

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MET 21100 Memo Lab Report Grading Sheet Expectations: The complete draft lab report was read/reviewed by ALL group members. Suggestions and corrections were considered, and incorporated where appropriate. The final version of the complete lab report was then reviewed by ALL group members prior to submission. Names : Peter Catizone M,W,F 11:30-12:20 Nate Montanari M,W,F 11:30-12:20 Quinn Steinkamp M,W,F 11:30-12:20 Lab Date - 11/9/2023 Lab Div# - 211000-008 Format/Grammar/Spelling 6 points Title Information 2 points Executive Summary 10 points Results 40 points Conclusions 10 points Data Sheet(s); references 2 points Subtotal: Attendance: Total score:

To: Dr. Sunghwan Lee From: Peter Catizone, Nate Montanari, and Quinn Steinkamp Cc: Shuning Yin Date: November, 16, 2023 Re: MET 211 Flexural Strain 4 Point Bending Executive summary This lab was completed as part of the MET 211 lab curriculum. This lab was also completed to demonstrate the effect that different magnitudes of force have on a beam within a bending test. The value that is to be collected from the lab is the strain affecting the beam in the units of microstrain. To effectively complete the lab the group was given access to a UTM machine, a four point bending fixture, P3500 strain indicator reading in micro strain, a steel rule, dial calipers, six specimens of varying heights from 1.5 to 3.5 inches in .5 inch increments. To complete this test the group was tasked with testing 2 of the given samples. To start the group inserted the beam into the four point bending fixture. Then the wires from the strain gauges located at the center of the beam were wired into the strain indicator. After that the group increased the tension and set the pins at a set distance apart using a steel separator bar. Thena after the specimen was set the data acquisition equipment could be zeroed. Once setup was complete the test could begin. To complete the test the group incrementally increased the force applied to the specimen in increments of 200 lbs until a force of 1400 lbs was reached, after each 200 lb increment was reached the strain data was recorded for later analysis. Once completed the specimen was returned to the original position and switched out for another sample. Once all the data was collected the group analyzed the results and found that as the height of the beam increased the strain that it experienced decreased. So the taller the beam was the less strain it received compared to beams of shorter height.

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Beam Height (in) Experimental Strain ( 𝝻𝝴 ) Theoretical Strain ( 𝝻𝝴 ) 2.0 223.6 196.8 2.5 146.8 100.8 3.0 100.6 58.3 3.5 50.3 36.7 Theoretical Experimental % Difference Slope, m 1576 1438.1 8.8% Constant, c -2 -2.564 28.2%

Sample Calculations: M Max = V*D = (375 N)(3.5 m) = 1312.5 N/m Theoretical: 𝝴 = 𝞼 /E = My/IE = [(1312.5)(2/2)]/[((1*2^3)/12)(1*10^7)] = 196.8 𝝻𝝴 Experimental: 𝝴 = m*P + b = 0.2968(750) + 1 = 223.6 𝝻𝝴 C th : 𝝴 th = C th *h^-2 = C th = (196.8)(2^2) = 1576 Percent difference: ((t-e)/t)*100 , = ((2.564-2)/2)*100 = 28.2 %

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Conclusion In conclusion the experiments and data found within the lab showed the group the effects geometry has on strain at varying loads. Through the testing using the four point bending fixture within the UTM machine provided valuable insight into affects that force has on strain in a bending scenario. Within the lab manual there are questions proposed to help the lab group think deeper about the experiments. The first question proposed was “How does the height of a beam affect the strain (and therefore, stress)? Can you relate this to any geometric properties? If not why?” The answer the lab group provided was that as the height of the beam increased the strain experienced decreased. To answer part two they added that the geometrical properties of larger beams being able to withstand more force applies. The more area there is resisting the force the less strain it will feel. The second question that the lab manual proposed is “How well did the strain gauges results agree with the theory of flexural strain?” To answer this the group looked back at the experiments completed within the lab and compared the values received from the p3500 strain indicator and the results calculated and found that they were within a reasonable amount of difference. There are always factors that can affect the experimental data such as differences in the metal improper setup and usage or bad equipment. So in conclusion the lab group decided that the results somewhat agree if the tests were completed with more accurate technology.. So in conclusion the group received good insight on how force applied and strain experiences are affected by geometrical properties. Through the results of testing in the lab it proved their theories that as the height of the beam increased the strain on the beam decreased.

Sources Roach, Thelen; MET 21100 Laboratory Manual , Purdue University: West Lafayette, IN, 2023

Data Sheet Week 10 - Flexural Strain - Data Sheet Material: 6061-T6-Aluminum E (psi): 10,000,000 Beam Height (in) Data Points 2.0 Load, F (lbs) 200 400 600 800 1000 1200 1400 Strain, 𝝻𝝴 62 119 177 237 300 359 415 2.5 Load, F (lbs) 200 400 600 800 1000 1200 1400 Strain, 𝝻𝝴 38 76 114 161 195 237 276 3.0 Load, F (lbs) 200 400 600 800 1000 1200 1400 Strain, 𝝻𝝴 28 55 80 107 132 160 189 4 Load, F (lbs) 200 400 600 800 1000 1200 1400 Strain, 𝝻𝝴 13 27 40 54 67 81 93 Measure for calculations: 1. Beam height (h) 2. Beam width (b), W = 1 inch 3. Distance between pins on the top of the fixture and bottom fixture

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