BEAM3 Element Description

BEAM3 is a uniaxial element with tension, compression, and bending capabilities. The element has three degrees of freedom at each node: translations in the nodal x and y directions and rotation about the nodal z-axis. See BEAM3 in the Theory Reference for ANSYS and ANSYS Workbench for more details about this element. Other 2-D beam elements are the plastic beam (BEAM23) and the tapered unsymmetric beam (BEAM54).

BEAM3 Input Data

Figure 3.1: "BEAM3 Geometry" shows the geometry, node locations, and the coordinate system for this element. The element is defined by two nodes, the cross-sectional area, the area moment of inertia, the height, and the material properties. The initial strain in the element (ISTRN) is given by Δ/L, where Δ is the difference between the element length, L (as defined by the I and J node locations), and the zero strain length. The initial strain is also used in calculating the stress stiffness matrix, if any, for the first cumulative iteration.

You can use the element in an axisymmetric analysis if hoop effects are negligible, such as for bolts, slotted cylinders, etc. The area and moment of inertia must be input on a full 360° basis for an axisymmetric analysis. The shear deflection constant (SHEARZ) is optional. You can use a zero value of SHEARZ to neglect shear deflection. See Shear Deflection for details. The shear modulus (GXY) is used only with shear deflection. You can specify an added mass per unit length with the ADDMAS real constant.

Node and Element Loads describes element loads. You can specify pressures as surface loads on the element faces, shown by the circled numbers in Figure 3.1: "BEAM3 Geometry". Positive normal pressures act into the element. You specify lateral pressures as a force per unit length. End "pressures" are input as a force. KEYOPT(10) allows tapered lateral pressures to be offset from the nodes. You can specify temperatures as element body loads at the four "corner" locations shown in Figure 3.1: "BEAM3 Geometry". The first corner temperature T1 defaults to TUNIF. If all other temperatures are unspecified, they default to T1. If only T1 and T2 are input, T3 defaults to T2 and T4 defaults to T1. For any other input pattern, unspecified temperatures default to TUNIF.

KEYOPT(9) is used to request output at intermediate locations. It is based on equilibrium (free body of a portion of the element) considerations and is not valid if:

"BEAM3 Input Summary" summarizes the element input. Element Input contains a general description of element input.

BEAM3 Output Data

The solution output associated with the element is in two forms:

Figure 3.2: "BEAM3 Stress Output" illustrates several items. Solution Output gives a general description of solution output. See the Basic Analysis Guide for ways to view results.

The Element Output Definitions table uses the following notation:

A colon (:) in the Name column indicates the item can be accessed by the Component Name method [ETABLE, ESOL]. The O column indicates the availability of the items in the file Jobname.OUT. The R column indicates the availability of the items in the results file.

In either the O or R columns, Y indicates that the item is always available, a number refers to a table footnote that describes when the item is conditionally available, and a - indicates that the item is not available.

The following tables list output available through the ETABLE command using the Sequence Number method. See The General Postprocessor (POST1) of the Basic Analysis Guide and The Item and Sequence Number Table of this manual for more information. Table 3.2: "BEAM3 Item and Sequence Numbers (KEYOPT(9) = 0)" through Table 3.7: "BEAM3 Item and Sequence Numbers (KEYOPT(9) = 9)" all use the following notation:

BEAM3 Assumptions and Restrictions

BEAM3 Product Restrictions

When used in the product(s) listed below, the stated product-specific restrictions apply to this element in addition to the general assumptions and restrictions given in the previous section.

ANSYS Professional.