Lab3

pdf

School

University of Central Oklahoma *

*We aren’t endorsed by this school

Course

2143

Subject

English

Date

Dec 6, 2023

Type

pdf

Pages

9

Report

Uploaded by HighnessScorpionMaster539

University of Central Oklahoma Slender Column Test - Experiment 3 Dylan Robinson, Joshua Jackson, and Kaleb Paddock Dr. Adnan Al-Ibadi Thursday 1:00 PM 10/6/22
Abstract Experiment 3 for the Strength of Materials laboratory covers a test of a slender column. In this experiment, the slender column specimen is loaded into the testing apparatus (Universal Testing Machine or ZPM) and an axial force is applied to the specimen. In this particular experiment, we are asked to calculate a theoretical value for the maximum axial load that can be applied before the specimen is pushed beyond a point where it can return to its original state. This experiment employs many of the concepts that we are familiar with from the lecture portion of the Strength of Materials class, and this experiment works to improve our understanding of those concepts. In civil engineering columns are used to support various structures. These structures can impose tremendous loads on the columns. In slender columns, sometimes loading can reach a point of near failure. At this point any variance in forces on the slender column causes it to buckle.[1] Machines and Instruments ‘Image 1’ shows the main machine use d in this experiment. This machine applies an accurate and measured force onto our test specimen, as well as measures the displacement of the specimen due to the force applied. This ZPM is different from the standard equipment and is the same test stand utilized in the previous experiment, the Tension Test. Using this information, we are able to test our theoretical value for the critical force applied before the specimen cannot return to its original stage, against a value we obtain during the experiment. Experimental Method In this experiment, we rely heavily on the concepts of stress, strain, modulus of elasticity, and a few other key concepts specific to strength of materials. A tensile test was conducted on an aluminum specimen using the ZPM described above. The data points for the precise force being applied as well as displacement measured in the specimen was recorded. Our role in utilizing the test stand was fairly limited. The Lab assistant ensured the test equipment was calibrated as well as conducting the operation of the test stand. After the specimen was tested, the data was aggregated and an analysis was organized.
Image 1: Specimen Loaded into the secondary testing machine. Test Procedure This procedure assumes the ZPM has been set up and calibrated. The test specimen is composed of Aluminum, which is helpful information for finding the modulus of Elasticity. The specimen has two cylindrical cuts at either end in order to mount the specimen into the testing apparatus. Mounting of the specimen included opening TestBuilder and setting the parameters for the tension test. Setting the parameters of the ZPM consisted of inputting the necessary information into the universal testing machine, such as velocity of the ZPM actuator, rate of force and what data needed to be collected. Once the parameters in TestBuilder were set the experimental procedure was carried out by the Lab Technician. From there, the Aluminum specimen was put onto the supports in the machine. From there the ZPM was started, and a load was applied to the specimen. Data from this tensile loading was recorded.
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
  • Access to all documents
  • Unlimited textbook solutions
  • 24/7 expert homework help
Ansys procedure To begin the ansys procedure, first the element was defined using the BEAM3 element. Then the material properties were given values of EX=2e5 and PRXY=0.3. After that the geometric properties were defined with a height and width of 10. Keypoints were then defined along with the lines and meshing. The solution was then found by applying the appropriate constraints and applying loads. Specimen Specifications The specimens dimensions are as follows: Length - 290mm Diameter - 6.0mm Material - Aluminum Image 2 shows a picture of the tested specimen . Image 2: Test specimen
Results Data collected is as follows:
After we collected the data (shown above), we can then draw comparisons for the calculated value for the maximum critical load that is applied to the specimen before it is permanently damaged. In this experiment, we employ the equation listed below in order to calculate the theoretical value of the load at which the specimen is permanently damaged. P=(π2E)/L e 2 Here, P is our critical load E is the modulus of elasticity of the material being tested ‘Le’ is the effective length of the specimen. For this experiment, our effective length is the same as our specimen length due to the fact that we used a dual-pinned end setup for the testing. Ansys Results ‘Ansys Results’ shows the final result from the Ansys procedure described above. This is the computational displacement that the member should encounter based on the prescribed notions. Ansys Results
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
  • Access to all documents
  • Unlimited textbook solutions
  • 24/7 expert homework help
Validation and Discussion Given the data shown above in our table above, we are able to calculate the value for our modulus of elasticity (E) from the maximum displacement value given - shown below in our appendix section. With our modulus of elasticity value obtained, we can calculate the maximum stress we obtained given the initial length of the specimen and the change in it. For our value of the maximum stress (shown in our appendix section), we had a value of 409.26 N of force applied to the specimen, which in turn gave us a value of 93.7 MPa for our maximum stress value. Unfortunately, in our experiment, we were unable to apply enough force to actually displace the specimen enough that it would be permanently displaced. This was due to the fact that the machine we were using was unable to apply the force necessary. Conclusion Although the alternate test stand was incapable of producing the forces necessary to cause the specimen to fail completely, we were able to achieve a predicted outcome up to the upper limits of the alternate ZPM. In the future a better demonstration may be achieved by using a ZPM that is capable of causing the specimen to fail. Despite challenges in the experiment, our understanding of the material properties involved was reinforced.
Appendix
REFERENCES [1] “Column Buckling and Why It's Important to Know About.” Tribby3d , 10 Aug. 2022, https://tribby3d.com/blog/column- buckling/#:~:text=Column%20buckling%20is%20a%20phenomenon,column%20can%2 0resist%20before%20buckling. [2] Khandaker, M. (2021). Laboratory Manual for Strength of Materials Lab . Department of Engineering and Physics (UCO). [3] Hibbeler, R. C. Mechanics of Materials . Pearson, 2022.
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
  • Access to all documents
  • Unlimited textbook solutions
  • 24/7 expert homework help