Plot the engineering stress versus engineering strain graphs in the low strain (

? Plot the engineering stress versus engineering strain graphs in the low strain (<1%) region to determine Young’s Modulus (E), 0.1% proof stress and strain at yield. Note that a linear regression line can be created easily in Excel for the elastic region by creating an additional column of strain values and adding the offset (0.001). By c licking on the new line and selecting the linear fit option thi s will produce a regression line . The option to display the regression equation will provide you with the slope (E). ? Plot the engineering stress versus engineering strain and true stress versus engineering strain graphs from zero strain up to failure. ? De termine the ultimate tensile strength, fracture stress , ductility and work to fracture . ? Determine the relationship between Vickers hardness and Yield Strength ? = x (VHN) g. ? Examine the fracture surfaces and describe the fracture process. ? Use CES Edupack ( available in the Mechanical Engineering 5 th floor cluster under Programs/Mechanical/ CES Edupack ) to determine which material you have tested for A, B, C and discuss your results vs what was expected from the database . Deliverables: - Each student should p roduce a brief but concise laboratory report containing an abstract, introduction, materials and methods, results, discussion and conclusion. Your report should include results of using the Materials Selector Database (CES Edupack) a s a means to determine which materials were used in the study (A, B, C) based on their appearance, fracture behaviour, and mechanical properties of your experimental laboratory . Introduce all background material initially in the Introduction of your report . The mater ials and methods should be as brief as possible . Y o u can include this laboratory procedure in an appendix and refer to it in your materials and met hods to keep this section brief. Also include a brief description of the on - line Materials Selector Database (CES E dupack) . The two required graphs for each material in the Results section are: (a) Engineering stress versus engineering strain up to yield. (b) Engineering stress versus engineering strain and true stress versus engineering strain from the start up to fra cture. These may be presented together in a single figure. The laboratory report accounts for 1 0 % of the overall module mark. EXPERIMENTAL METHOD Follow instructions carefully – ask for assistance when you do not understand! Important Safety Notice: ? Forc es may reach in excess of 50kN – 5Tonnes. Keep your hands clear of the machine when the load is being applied. ? Keep clear of the machine. The door is not a safety guard; it is only to stop d ebris. ? Ensure you wear safety glasses at all times. ? Keep the d oor closed when the test is running. ? Following every measurement interval, ensure the door is closed before you continue the test. ? If you need to stop the machine in an emergency, press the red stop switch. Tensile test protocol : 1) Familiarise yourself w ith the software and the logos below: Console settings – Here, you can reduce the jog speed of the cross head, or return it to normal Strain 1 settings – the settings for strain gauge, where you can calibrate or balance the strain gauge. Load cell settings – The load cell is calibrated and balanced here. You do not need to do this during this exercise, as it will be done prior to testing for you. Crosshead settings – To balance or set limits on the crosshead. You do not need to do this during t his exercise, as it will be done prior to testing for you. 2) On Bluehill’s first page (see image below) , three boxes display the current status of the machine. The far left box shows the extension, which needs to be zeroed before start of test. The load i s shown in the middle box, and the strain is shown on the right hand side. click on Test . Laboratory Notes – Read after you have completed the lab In the first part of the lab you measured the initial diameter and the overall gage length. You measured engineering strain, vs applied load in the elastic region. You then removed the strain gage. - from this you can calculate the eng stress, eng strain. Strain was measured directly by the strain gage; when you removed it this goes to zero or negative, ignore this. You can plot eng stress v eng strain and solve for the elastic modulus and the yiel d strength (use a proof str ess if needed). In the second part of the lab the machine recorded the deformation. You measured the change in diameter and load as necking occurred. You measured the final load and final area and final length. - you can est imate the eng stress, eng strain, true stress, true strain. Stress is force/ area, strain is the change in length / original length. This is an estimate as the change in length used to calculate strain is measured by crosshead deformation in this part (s train gage was already removed, ignore this) and the overall cross sectional shape of the entire specimen is not constant, particularly at the collars where the specimen is much larger. You can do the calculations in Microsoft excel or any spreadsheet a nd paste the results graphs into microsoft word processor. If using excel you can do the equations and copy them so the equation is applied to a whole row or selected column. Look at the cells in the online sample and the equation will be there usually i n the form... =b1*c1 this multiplies two cell locations =b1/c1 this divides two cells You can copy this equation down a row or across a column by highlighting the source cell with your mouse, doing Ctrl C, then highlighting the destination cells and p ressing Ctrl V. If you place a $ value in front of any of the characters in the equation it keeps these constant, if you do not they increment when copied. To plot data, select the data with the mouse, then click insert a graph by selecting the format d esired. If you have the axes mixed up you can simply select the line in the graph and make the corrections so it picks the right one. Once you have drawn a line the right mouse button selection allows you to conduct a linear regression of the line (only choose the section of the line that is linear for this, you may have to truncate the data selected for plotting the line to the linear part only) and select the option to show the equation on the chart, the slope of the equation should be your elastic modu lus. To calculate an offset line copy the equation into a cell and vary the values by picking a range of stress values (in ranges of 50 or 100 MPa for example) and solving for strain or vice versa, you can then add the offset to the strain column using an equation like =C4+0.01 this would add a 1% strain offset value to a cell in c4. if the rest of the values were below you could copy this equation downwards to get the entire set of new strain data. You then want to plot stress vs the new strain value s to get the offset line and then estimate where this crosses the experimental data line, by eye . Note: spreadsheets like excel plot data, they do not know how one set of data is related to another even if you have calculated the equation for the line. Hence excel cannot find the point where two lines intersect for you. Learning how to use a spreadsheet effectively is essential in engineering, and will take a lot of trial and error to get it right, expect to spend many days on this if you have never used one before. You do not have to use microsoft products, they are all similar, in fact many are much b etter (Microcal Origin for example can do good 3D surface plots, excel can only do 2D and is very poor in this area). PLACE THIS ORDER OR A SIMILAR ORDER WITH US TODAY AND GET AN AMAZING DISCOUNT :)