Finite Element Analysis for a Knuckle Crane Boom

A knuckle crane is a very unique crane due to its ability to bend and reach the
place near it based and increased in payload with smaller size body compared to
other crane. In order to implement the used of knuckle crane in various condition, an
analysis should be done to understand the behavior of the crane. From the result of
the analysis, a solution can be made possible as to increase the ability of the crane
and make it more efficient in various working environment. The project objectives
are to study the stress profile on the knuckle crane boom using finite element
analysis method. The effect of the different material on the maximum stress of the
crane under specific load will be included in the scope of study.
In this project, a 3D model of knuckle crane boom is made using Autodesk
inventor 2012 based on the drawing of the reference crane that is selected. The model
of the knuckle crane boom is drawn in 3 parts which each part of the crane is
assembled before the model is simulated using finite element method. Load is
applied to the model based on the load chart provided with the reference model
throughout the simulation process. Second objective is achieved by assigning
different material on the model and simulated. Result will be compared again current
material which is high-strength low-alloy steel and recommendation will be made.
The project result will identity the maximum location of stress profile on the
boom structure and the best material that can be used in crane manufacturing
process. Stress analysis on the model based on the load chart proves that the highest
concentrated stress is at the assembly point where the area is small enough to
develop high stress. Second reason for the stress distribution to behave as shown in
the result is due to the existed joint, pin joint, between the main boom and the second
boom structure.
Thus, it can be concluded that the strength of the joint is more as the
contributed factor to the limitation of the crane lifting capability compared to the
boom itself. It is proved that stainless steel 440c is the best material for boom
manufacturing and it is believed to be one of the solutions for high end crane
product. However, the process of implementation the material in current world might
have some difficulty in term of cost and manufacturing ability.