I am currently learning ANSYS Fluent for my research. There are also many great YouTube videos about this. To inspire myself to keep learning and also to record part of life, I want to summarize the analysis results of transient flow over a cylinder in this post.

I am using different spring elements for different directions in local coordinate system in ANSYS. At first, I could only add spring elements in global system even though I defined and activated local system, it just didn’t work. I searched on Google without satisfying results. Fortunately, I got this problem successfully solved with the help of a friend.

I switched from ABAQUS to ANSYS for my current research, though I am more familiar with ABAQUS. I currently have all the APDL for my model and want to do parametric analysis which requires about 7 to 8 hours for the calculation of one model with 2 cores. To improve the efficiency of running macro files in ANSYS, I decide to use MATLAB to run ANSYS.

I want to extract reaction force and displacement of a certain point, which is a reference point established in INTERACTION module and set as a geometry set named ‘SET-3’. The error information will pop up when using the codes I often use, as ‘KeyError: SET-3’, which can be seen in the second code part.

About one year ago, I tried to analyze a bolted T-stub to test the analysis method of bolted connections and verify my abaqus model referring to a journal paper, unfortunately, I could not find that paper now. Though I would not focus on steel connections in the future, I still want to make a summary of this simulation in order not to waste the effort one year ago.

I analyzed a specimen of ductile material with explicit dynamic method about one year ago. Recently, I want to review the model and summarize the process of analysis.

I want to analyze a steel frame with pin connections at both sides or one side at some beams. I found the keyword *Release is very useful and convenient, so I resort to this keyword. I wrote the input file with the same syntax rules, so that it will be more convenient for me to establish more models. However, when I try to run the input file, there are warnings and errors even with the input file generated from a successfully run job in CAE. The problem is described in the following figure.

Calculation of transverse shear stiffness

Definition

The effective transverse shear stiffness of the section of a shear flexible beam is defined in Abaqus as

\[{\overline K _{\alpha 3}} = f_p^\alpha {K_{\alpha 3}}\]

where \({\overline K _{\alpha 3}}\) is the section shear stiffness in the \(\alpha\)-direction; \({K_{\alpha 3}}\) is the actual shear stiffness of the section having units of force; and \(\alpha = 1,{\kern 1pt} {\kern 1pt} {\kern 1pt} 2\) are the local directions of the cross-section. \(f_p^\alpha\) is a dimensionless factor used to prevent the shear stiffness from becoming too large in slender beam elements and is always included in the calculation of transverse shear stiffness defined as

\[f_p^\alpha = \frac{1}{{1 + \xi \cdot SCF\frac{{{l^2}A}}{{12{I_{\alpha \alpha }}}}}}\]

where l is the length of the element, A is the cross-sectional area, \({{I_{\alpha \alpha }}}\) is the inertia in the \(\alpha\)-direction, SCF is the slenderness compensation factor (with a default value of 0.25), and \(\xi\) is a constant of value 1.0 for first-order elements and 10⁻⁴ for second-order elements.

Beam elements in ABAQUS make me a little confused, especially about the shear stiffness and elements for open sections. In this post, I want to make a summary of the elements in ABAQUS and give an example about the settings of beam elements.

Beam element library

Beam elements in a plane only have active degrees of freedom 1, 2, 6. Beam elements in space have active degrees of freedom 1, 2, 3, 4, 5, 6. Open section beams in space B31OS, B31OSH, B32OS, B32OSH have active degrees of freedom 1, 2, 3, 4, 5, 6, 7. The beam elements in ABAQUS Standard and Explicit (v6.14) are summarized below.

2D frame

This is a plane steel frame with box sections subjected to a point load at one node figured as below.

An dynamic implicit analysis step was defined and the following lines were added at the end of input file.

**
*STEP
*MATRIX GENERATE, STIFFNESS, MASS, LOAD, Structural Damping,Viscous Damping
*MATRIX OUTPUT, STIFFNESS, MASS, LOAD, Structural Damping,Viscous Damping, FORMAT=COORDINATE
*END STEP