Lauren Wagner Section 09 Jan 27 2022 Professor Lodhi LAB 1 Notch Sensitivity of Low Ductile Materials OBJECTIVE PROCEDURE DATA AND RESULTS Equations To see how a notch stress concentration in a low ductile material will affect the effective strength of the material First our lab group measured the width thickness and ligament width all in mm Then we found the net notch depth by subtracting the ligament width from the total width of the specimen Next our lab group found the failure load N by using the MTS Criterion tension testing machine To do this our group loaded the specimen into the machine and inserted the dimensions then started the test After we collected the data from the test and found the failure load Lastly our group toke all the data collected and was able to find the total area of the specimen the area of the ligament the percent full specimen area and the effective strength of the ligament and plotted the effective strength of the ligament vs the percent full specimen area o Total area Width Thickness Ex 31 66 mm 1 56 mm 49 3896 mm 2 o Alig ligament width thickness Ex 28 36 mm 1 56 mm 44 6628 mm 2 o A Alig toatal area 100 Ex 44 6628 mm 49 3896 mm 100 90 42956412 o eff lig failure load Alig ex 13417 976 N 44 6628 mm 300 428455 MPA 6061 T6 6061 T6 6061 T6 7075 T6 7075 T6 7075 T6 ST1011A Material Specimen Thickness t mm Net Notch Depth a mm Ligament Width wlig mm Width w mm 31 66 31 66 31 66 31 72 31 67 31 62 31 75 1 2 3 1 2 3 1 56 1 56 1 56 1 6 1 57 1 63 1 52 3 03 6 09 9 38 3 91 5 94 9 33 2 41 28 63 25 57 22 28 27 81 25 73 22 29 29 34 Failure Load mm P 13417 976 11618 354 9955 775 15896 562 12508 602 11139 643 12859 31 7 1 42 4 14 27 56 11462 31 71 31 73 31 72 31 76 1 42 1 52 1 53 1 58 4 11 0 97 2 58 4 195 27 6 30 76 29 14 27 565 11456 19712 17296 16202 Material Specimen Alig A eff lig Total Area A 49 3896 49 3896 49 3896 50 752 49 7219 51 5406 48 26 45 014 45 0282 48 2296 48 5316 50 1808 44 6628 39 8892 34 7568 44 496 40 3961 36 3327 44 5968 39 1352 39 192 46 7552 44 5842 43 5527 310 100 300 428455 90 42956412 80 76437145 291 2656559 70 37271004 286 4410705 100 572 87 67339218 357 2582255 81 24407957 309 6487532 70 49335863 306 6010233 100 340 92 40944882 288 3390737 86 94006309 292 8821112 87 03878903 292 3045519 100 440 96 94295619 421 6001643 91 86633039 387 9401223 86 79156171 372 0090832 ST1011A ST1011A ST1018 ST1018 ST1018 6061 T6 6061 T6 6061 T6 6061 T6 7075 T6 7075 T6 7075 T6 7075 T6 ST1011A ST1011A ST1011A ST1011A ST1018 ST1018 ST1018 ST1018 1 2 3 1 2 3 ANALYSIS OF DATA Determination of specimen full area o Total area Width Thickness Ex 31 66 mm 1 56 mm 49 3896 mm 2 Derivation and determination of ligament area o Alig ligament width thickness Ex 28 36 mm 1 56 mm 44 6628 mm 2 Calculation of percent of full specimen area o A Alig toatal area 100 Ex 44 6628 mm 49 3896 mm 100 90 42956412 Calculation of ligament effective ultimate strength o eff lig failure load Alig ex 13417 976 N 44 6628 mm 300 428455 MPA DISCUSSION OF RESULTS If an alloy is flaw or notch insensitive the ligament effective ultimate strengths would not depend on the effective cross sectional areas Is alloy sensitive to the presence of geometrical discontinuities Support your response with references to the four sets of data collected The different alloys are sensitive to the presence of the geometrical discontinuities This is because the tensile strength of the effective ligaments that were tested would be all the same if it mattered on the effective cross sectional area they are sensitive because they matter on the notch depth A very soft and ductile Aluminum alloy 1100 is the type commonly used in electrical conductors Based on your experiments what would your expectations be as to its notch sensitivity I would expect it to have a lower notch sensitivity this is because the aluminum alloy is very ductile and looking at the data that was collected the lower the ductile the lower the notch sensitivity was If the material was brittle then the notch sensitivity would be higher Comment on the fracture surfaces Were they expected for this kind of test The fracture surfaces were expected during this test This is because they were needed to find the fracture stress and the ultimate strength The surfaces were brittle if the surfaces that broke were very straight across and smooth The surfaces that were ductile were able to bend and stay intact longer than the brittle materials CONCLUSION During the lab the difference between materials and their notch sensitivity was determined by looking at the fracture stress and ultimate strength The data was able to be gathered from the MTS Criterion tension testing machine