Question

The cross-section width is measured three times with the values 13.59 mm, 13.53 mm and 13.66 mm. the cross-section thicknesses are measured three times with 3.15 mm, 3.26 mm, and 3.15 mm, respectively. The gage length of the sample is 113.08 mm. The load- displacement curve is shown in Fig. 1. After experiment, the dimensions of the fracture cross-section are measured, with width 11.94 mm and thickness 2.32 mm, respectively as shown in Fig. 2. The yield force is 4537.5 N, and its corresponding elongation is 0.991 mm. the break (fracture) force is 11850 N, and the corresponding elongation is 12.367 mm. The following problems should be addressed in the report: 1. the stress-strain curve of this test sample. 2. an approximate Young's modulus of the aluminum from this test result. 3. yield strength of the sample. 4. the real stress at the fraction cross-section of the sample. 5. necessary comments on this test result.

Answer 1

Averaye width Average thickmes Sol 3-59+ 13.53 + 13-66 13.5933 mm t = 3-15 3.26+ 3-)5 3-1867 mmm Cnoss ecton asea A bt 3.5933 x3-1867 1 43.3174 mm A = OT jield tarnh gield force 4537.SN O4-75 MPa 43.3174 mm 2 Aey 3 Smce strers force dichlacement original Aerythe thain Area Se for all vafus foeethir corresponding dislacenentfoorm given lot you can cal culate staun&its correpenching coiy strain So then plot the stre-strain cunve with Atren on y axis&stain om x aris for bant 1 elonyation at yield aigimal ing th Atnain at yield O.991 = 8.7637x0 13.o8 E = yield strus yielel stnain Jontmg modusus Jo4.75 8.7637x10 11952-7mPa Ans 2 Real Cnoss sechon anea at fhacture real strens at fracture 1-94X 2.32 = 27.7008 mm2 1850 N 27.700 8 mm2 427-78 MPa The staers-strain cunve will be bacd on Cnoss ectionYathen than real anea from the real stre-strai cenve Emgineering Ait will be difernt area Se the failure stnes fron the Cnve will be different from the real stres at failu