Computer Aided Modelling and Analysis Laboratory 20ME68 Exercises Stress analysis of Bars of 1.Constant area Prepared by: Vinayaka G P Course Coordinator, CAMA Lab Department of Mechanical Engineering Vidyavardhaka College of Engineering, Mysuru
Analysis of: “Bar of Constant Area”
For the simple steel bar of cross-sectional area 500mm 2 ,length 900mm and the Young’s modulus E=2×10 5 N/mm 2 ,Determine the following when it is subjected to the following loads “P”: Tensile load of P= 800N Compressive Load of P=700N Reaction force at the support Nodal stress Deformation. Assume Poison’s ratio of 0.3 P 900 mm Problem Statement
Problem Statement Analysis Problem Domain: Structural Element type & its geometry: Bar of Uniform Cross sectional Area. Material and Young’s Modulus: Steel, E =2.1e 5 Cross Sectional Area: 500mm 2 Length of the Element: 900mm Magnitude & Nature of the Load: 800 N tensile and 700N Compressive.
Parameters to be Determined
Problem Solution by Strength of Material Approach
Calculation of Reaction Force Consider Tensile load of P = 800N Considering sum of forces in X -direction Σ𝐹 x = 0 𝑅x+ 𝐹x = 0 𝑅x = -800𝑁 Consider Compressive load of P = 700N Considering sum of forces in X -direction Σ𝐹 x = 0 𝑅x- 𝐹x = 0 𝑅x = 700𝑁 F x R x F x R x
Calculation of Stress Consider Tensile load of P = 800N Stress induced in the Bar: F =800N A= 500mm 2 = 1.6 Nmm -2 Consider Compressive load of P = 700N Stress induced in the Bar: F =700N A= 500mm 2 = 1.4 Nmm -2
Calculation of Deformation Consider Tensile load of P = 800N Deformation of the Bar: P =800N L = 900mm A= 500mm 2 E= 2.1e5 Nmm -2 𝛿𝑙= 6.857 × 10 -3 𝑚𝑚 Consider Compressive load of P = 700N Deformation of the Bar: P =-700N L = 900mm A= 500mm 2 E= 2.1e5 Nmm -2 𝛿𝑙= - 6× 10 -3 𝑚𝑚
Problem Solution through ANSYS
ANSYS-APDL Procedure Ansys Utility Menu File – Clear and Start New-Read File – ok –Verify –Yes File- Change Title-Enter “Analysis of Bars of Uniform Cross Section”- Ok File – Save as- Save Database to- Type file name as “Analysis of Bar of uniform cross section”-Ok. Main Menu: Material Properties Preferences- Structural-Ok. Preprocessor- Element type –Add/Edit/Delete-Element types-Add-Link-3D Finit stn 180-Close. Preprocessor-Material Props-Material Models- Structural –Linear-elastic-Isotropic-EX: 2.1e5 (Youngs Modulus) –PRXY: 0.3(Poisson’s ratio)- Close. Preprocessor-Sections-Link-Add-Section Data: Link Area -500 (Cross sectional area)-Ok.
ANSYS-APDL Procedure Main Menu: Model Creation Preprocessor- Modelling-Create-Nodes-In Active CS: Node Number: 01-Location in Active CS: 0,0,0 (X,Y,Z). Node Number: 02-Location in Active CS: 900,0,0 (X,Y,Z). Preprocessor-Modelling – Elements-Auto Numbered- Thru Nodes- Pick Nodes-Pick Node 1 and 2-Ok. Main Menu: Load Application Preprocessor-Loads-Define Loads-Apply-Structural-Displacement-On Nodes-Pick Node 1-DOFs to be constrained-All DOF-Displacement Value: 0- Ok. Command Prompt-f,2,FX,800.
ANSYS-APDL Procedure Solution Solve-Current LS-Ok-Solution is Done-Close. General Post Processor Plot Results- Deformed Shape- Def+Undeformed -Ok- Record deformation Value :DMX =0.00687 List Results-Reaction Solu- All Items-Ok-Record the Reaction force: FX =-800N Nodal Solution- Stress- Von Misses Stress- Record the stress value : 1.6Nmm -2
Results: Problem Type Parameters Analytical Approach Experimental Approach Error Bar with Constant Cross Sectional Area 1.Reaction Force 2.Deformation 3.Stress -800 N 6.857 × 10 -3 1.6MPa -800N 0.006857 1.6MPa
ANSYS-APDL Procedure For Compressive Load follow the same procedure with P value as given in the problem statement. Compressive Load to be given as: f,2,FX,-700