In this exercise a data file with the geometry data and minimal analysis data is provided as a starting template in mech_001\Exercises\Case 2A\data\mech_001_2d_case2a.dat and the user is encouraged to complete the data required to solve the problem described. In mech_001\Exercises\Case 2A\data reference the completed data file is provided.

 

The objective of this exercise is to simulate the stress state in a sandstone cylinder subjected to  internal and external surface pressure.   The material properties are identical to the previous exercises and the cylinder has inner and outer radii of 50 mm and 200 mm respectively.   Symmetry can be used on both the X and Y axes so that only one quarter of the cylinder is analyzed.  The pressure loading should be defined using an S-Curve load over a time of 100s and Time_scaling_factors should be defined so that ca. 1000 steps are used to compute the solution.  2% damping should also be applied using the Damping_global_data data structure.

 

The geometry for the problem is defined using two four sided surfaces (see below) and provided in data file mech_001_2d_case2a.dat.  The geometry allows either a structured or unstructured mesh to be used for the simulation.   An unstructured mesh should be used with default element size = 10 mm and an element size of 5 mm assigned to the lines defining the inner radius of the cylinder (see mesh_001 Case1C).

 

Both global history (History_global) and point history (History_point) should be defined with output time intervals of 0.5 s.  Global history should output kinetic and elastic energy.   Point history should output X-displacement ("Disp_x") and stress component σxx ("Strs_XX") at locations (X, Y)=(51, 1) and (X, Y)=(199, 1).

 

 

 

Unstructured Mesh (Default Size = 10mm, Inner Surface Size = 5mm)

 

Output processing should comprise time histories of radial stress and radial displacement and a contour plot of the radial stress (principle stress 22) in the final configuration.  The target output solutions are shown below.  The reference solution data is provided in mech_001\Exercises\Case 2A\results

Contours of Radial Stress in the final configuration