MET 211 Lab Report 11

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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 - 11/29/2023 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: December 6, 2023 Re: MET 211 Combined Normal Stress Executive summary This lab was completed as part of the MET 211 Lab curriculum. The goal of this lab was to show the group the stress strain comparison of a beam. To complete this lab the lab groups were given access to a Steel “C” Clamp with strain gauges mounted, a Micro Measurements P-3500 strain Indicator or a P3 Strain Indicator, a 0-1 inch Micrometer with .001 inch graduations, a set of dial calipers with .001 inch graduations, and a steel rule. This lab was a very quick lab to complete. To start one group member started the clamp on the edge of the table and then zeroed the strain indicator. After the strain indicator was zeroed another group member turned the handle in ¼ turn increments and other group members recorded the data. Once the handle had been turned a full 2 revolutions it could be backed off and put back down onto the table. Once the data was all recorded the group then analyzed the data and recorded the results. The results that the group found the tensile forces the clamp bar was receiving were greater in magnitude than the compressive forces the bar was feeling.

Results Equation Filled out Equation Result Centroid(X) Σ(A i X i )/A [(0.31*0.31)+(0.38*0.87)]/0.69 0.618 in Area(A) L 1 W 1 +L 2 W 2 (0.5*0.62)+(0.765*0.5) 0.69 in Area Moment of Inertia (I Z ) Σ(I i +Ad i ^2) [(((0.62)(0.5^3))/12)+(0.31(0.61 8-0.31)^2)]+[(((0.5)(0.765^3))/ 12)+(0.38(0.618-0.87)^2)] 0.084 in^4 Moment arm L meas (7.92) 7.92 d i W 1 +W 2 (0.62+0.5) 1.12 in X COMPRESSIVE 1/2W 1 (0.62)/2 0.31 in X Tensile W 1 +1/2W 2 0.62+(0.5/2) 0.87 in Number of Turns Clamping Force Clamping Force Tensile Force (lb f ) Tensile Strain ( 𝞵𝞮 ) Compressive Force (lb f ) Compressive Strain ( 𝞵𝞮 ) ¼ 11.49 5 16.12 3 ½ 103.45 45 166.59 31 ¾ 211.51 92 360.05 67 1 310.36 135 526.64 98 1 ¼ 397.72 173 687.85 128 1 ½ 491.98 214 859.13 160 1 ¾ 588.54 256 1026.40 191 2 678.20 295 1192.99 222

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E = 30 X 10 6 psi I z = 0.084 in^4 A = 0.69 in

Sample Calculations F Tensile = (E* 𝞮 tensile )/[(1/A)+(d*x tensile )/I z ] = ((30*10^6)*(5*10^-3))/[(1/0.69)+(1.12*0.87)/0.084] = 11.49 lb f F Compressive = (E* 𝞮 Compressive )/[(1/A)+(d*x Compressive )/I z ] = ((30*10^6)*(3*10^-3))/[(1/0.69)+(1.12*0.31)/0.084] = 16.12 lb f % Difference = (m theoretical - m ideal )/ m ideal *100 = (0.57 - 1)/1 *100 = 43%

Conclusion In conclusion the results that the lab tests yielded provided valuable information in learning the inverse relations between stress and strain when referring to beam bending. Through testing the clamps normal forces using a strain indicator the group learned how compressive stain is inverse to tensile strain. The lab manual poses a variety of questions for labs to help the lab groups get a further understanding of what the data is showing them. The first question the lab manual poses for this lab is “Are the calculated clamping force values the same for both the tensile strain and compressive strain calculations? Why or why not?”. To answer this the lab group stated in theory the values would have to be close because as one side contracts the other side expands. In this case due to some of the values possibly being off the calculated values were close but not the same. The second question the lab manual poses is “What are potential sources of errors in this experiment?”. The group stated for this question there is a long list of errors that could go wrong but considered some of the main few. The first one is clamp mounting, if the clamp is mounted at an angle or not at the right pressure when zeroed it could skew the results. A second major error could come from material defects or differences. Not all metal is exactly the same and the same goes for the wood the clam is mounted on, so if the material was slightly different from other groups it could have a potential difference in the data. Finally the strain gauge. AS the group learned from a previous lab it can be difficult to properly mount a strain gauge let alone two so some errors could result from improper placement, wires not being soldered correctly, or damage occurring from the repeated use through the different lab sections. While there could be many more factors that could cause errors, the group found that these were some of the main concerns.

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In conclusion the group learned more about normal forces through analyzing the compressive and tensile strain results of a compressed “C” clamp at different forces. They also learned more about some errors that could go wrong in either material or user error.

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

Data Sheet Chapter 13 Combined Stress with Partial Results Lab Date: 11-29-2023 Lab Day and Time : Thursday 11:30 to 1:20 Lab Division: 008 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 Number of Turns Tensile Strain ( 𝞵𝞮 ) Compressive Strain ( 𝞵𝞮 ) ¼ 5 3 ½ 45 31 ¾ 92 67 1 135 98 1 ¼ 173 128 1 ½ 214 160 1 ¾ 256 191 2 295 222

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