Finite Element Analysis of Cable Anchor

Problem Statement

The cable anchor to be analyzed is used to support large communications and broadcast transmission towers which are getting taller and taller everyday.

The challenge of this project will be to analyze the stresses that are seen by the arms on the cable anchors that support these larger communication towers and observe the effects that the rib have on the design. The design of the anchor must withstand (not yield) the 250,000 pounds of structural weight and wind loading that is applied. A possible improvement to the design will also be presented.

ARM

Problem Formulation

A cable-anchor is a component at the end of the guy wire that helps to anchor the guyed tower. It is almost 2 feet long and about 60 pounds. The anchor to be analyzed is manufacturing from austempered ductile iron (ADI) and as can be seen from the figure it is only loaded in tension. As was mentioned previously the maximum tensile load that is applied to the anchor has a magnitude of 250,000 lbs.

First make Pro-E ModelUse same dimensions are real model

RIB

Finite Element Modeling with Ribchecking mesh-Using a 0.075 mesh, no H-adaptivity

Finite Element Modeling (cont.) Improving mesh - Using a 0.1 mesh and H-adaptivity

Finite Element Modeling (cont.) Improving mesh - Using a 0.075 mesh and H-adaptivity

Finite Element Modeling (cont.) Acceptable mesh (minimal change in stress from previous) - Using a 0.05 mesh and H-adaptivity

Finite Element Modeling (cont.) Symmetry could be used to speed-up processing

Introduce appropriate boundary conditions for symmetry

Finite Element Modeling (cont.) Rib was removed to observe its effects

Comparing stresses with and without the rib

With Rib Without Rib

Comparing deformations with and without the rib (observe deformation scales)

With Rib Without Rib

Possible AlternativeAdding piece of pipe that could prevent deflection instead of adding the rib.

FEA of Proposed AlternativeCan observe the reduction of stresses after adding the pipe and without the rib.

New b.c. for addition of pipe

Use of material in the arms of alternative and anchor with rib.

With Rib With Pipe

Areas of interest

Comments An attempt was made to use an appropriate mesh for the

analysis. The comparison between the whole anchor and the

symmetry anchor supports the use of symmetry. By comparing the stresses and deformation of the

anchor with and without the ribs we are able to observe the effect that they have on the design.

A possible alternative of adding a pipe between the arms instead of the ribs is presented. FEA was performed on this alternative. Results showed that by adding the pipe, the stresses of interest are reduced slightly lower than by adding the rib. Furthermore, this alternative presents a more judiciously use of material in the arms of the anchor.