Previously, due to some requirements, I need to extract coordinate data from a deformed image and found that Mathematica can indeed do a lot of things. So, I combined information from forums and help documents to see if there was anything interesting to explore. I discovered that Mathematica can perform image matching, and thus I wanted to use Mathematica image matching to locate the position of a small part of an image within a larger image.

Creep is a typical nonlinearity problem due to material. For such problem, it is necessary to understand the material properties and correctly setting the material related attributes. In Ansys, setting up creep behavior involves activating the material’s Creep option and assigning it elastic properties. This post analyzes a bolt in operation, with a length of 200mm and a cross-sectional area of 150mm^2, continuously working at 800°C. The goal is to analyze the internal stress evolution/condition of the bolt, as shown in the model below,

In steel structure design, the calculation of component stability is more crucial than the calculation of component strength. Linear buckling analysis tends to be conservative, thus solely conducting a linear eigenvalue analysis is insufficient now. To achieve results closer to real-world engineering scenarios, it is essential to perform nonlinear buckling analysis. In Ansys, the STATIC analysis combined with the application of the arc-length method enables a comprehensive buckling analysis of the component throughout the buckling process.

Beam elements are recognized for their simplicity and efficiency, making them widely used in finite element analysis, especially within structural engineering. Utilizing beam elements avoids the requirement to model all components as solid elements, thereby reducing computational effort. Beam elements provide a straightforward structural format with relatively high accuracy. In Ansys, beam elements are generally classified into linear and quadratic elements, with different computational theories. The integration points for the classic quadratic element, BEAM189, are shown in the following image:

This article analyzes a tapered collet in operation. Tapered collets are commonly used mechanical devices that employ sleeve compression to clamp workpieces. This involves friction between the sleeve and the clamp, as well as between the clamp and the workpiece. The frictional force can be determined when the workpiece is pulled. This provides insight into the load-bearing capacity of the entire mechanical assembly. A cross-sectional view of the model is illustrated below,

In practical analyses, nonlinear contact between structures or components is frequently encountered. Contact problems, a type of nonlinear behavior, often require significant computational resources. To conduct a analysis, it is essential to establish an effective model. Setting up contact analyses in Ansys typically involves two main issues:

In structural engineering, Ansys is predominantly used for elastic analysis or elastic-plastic analysis of steel structures. However, when dealing with reinforced concrete frames, Ansys sometimes has issues, primarily because the concrete material in Ansys is intended to be used with the SOLID65 element. While most building structures consist of frames, simulating all elements/frames of a structure with SOLID65 requires substantial computational cost and also poses a convergence challenge.

During structural analysis, it is common to use multiple types of elements together. This leads to issues related to the connection between elements. General elements like beams, shells, and solid elements usually connect via shared nodes. However, due to the differences in degrees of freedom (DOF) between elements, such connections might not yield the desired results and can even lead to issues that prevent model convergence. Thus, it is necessary to create “compatibility conditions” between different elements.

Previously, when I analyzed a steel structure with residual stress, it is difficult to apply residual stresses correctly and could not identify the problem until I came across a case study on applying residual stresses. In Ansys, initial stresses can be considered as a load but are only applicable in static and transient analyses. Constant initial stresses can be applied using the ISTRESS command.

The Drucker-Prager (DP) material model in Ansys is a non-metallic material model that can consider volume expansion caused by yielding. Thus, it is suitable for simulating granular materials with friction, concrete, rocks, etc. Unlike metallic materials, the DP material model can use both associated and non-associated flow rules. However, the DP material does not have a hardening rule and its yield surface expands with an increase in hydrostatic pressure, exhibiting ideally elastic-plastic behavior. The equivalent stress for the DP model is defined by the following equation,