Services
Finite Element Analysis (FEA)
Finite Element Analysis (FEA)
When it comes to designing a structure, having access to as much information as possible is crucial to making informed decisions. At NETSCo, we have a team of highly-skilled and experienced engineers who use Finite Element Analysis (FEA) software to optimize and analyze designs at an early stage, saving our clients both time and money.
Our FEA services are incorporated into the design review process to increase the accuracy of a design and ensure that it meets the client’s performance standards and requirements. We use the world’s most advanced software in virtual prototyping, reducing R&D and development costs.
With FEA, you can eliminate risk by analyzing critical design parameters such as stress, strain, failure points, fatigue, stages of creep, thermal conduction, convection, radiation, conjugate heat transfer, harmonic, random, transient dynamic vibrations, and seismic equivalent static, response spectrum, transient dynamics. Additionally, we offer impact and crash analysis using precise simulation or equivalent static force.
Whether you need FEA services for troubleshooting, optimizing a design, validating a vessel modification, or ensuring quality control for product replacements, our engineering team has the knowledge and experience to meet your needs. Choose NETSCo for efficient, effective FEA services that guarantee the success of your project.
Case Study: A Forensic Analysis of Rudder Horn Failures in a Bulk Carrier
In the maritime industry, structural integrity is vital, especially for vessels that endure harsh conditions and heavy loads on the Great Lakes. These bulk carriers experienced structural failures in and near the rudder horn, prompting an in-depth investigation by NETSCo. This case study focuses on the forensic analysis using Finite Element Analysis (FEA) of the rudder horn casting and the surrounding ship structure to identify the root causes of these failures and propose effective solutions.
The bulk carrier encountered significant structural issues, with cracks forming in and around the rudder horn. These failures posed a risk to the vessels’ operational safety and longevity. The primary challenge was to determine the stress concentrations and their magnitudes in the rudder horn and adjacent structures and to identify the reasons for these failures.
As part of NETSCo’s scope of work for the forensic analysis of the ship’s rudder horn, a detailed Finite Element Analysis (FEA) was completed. The analysis focused on the rudder horn casting piece and the ship structure immediately surrounding it. FeMap Version 11.4.2 was used for pre and post processing of the model, and the embedded NX Nastran Version 11.2 served as the finite element analysis solver. The geometry was built and manipulated in Rhinoceros 3D Version 5.0. This FEA was a linear static analysis, excluding considerations for crack propagation or material fatigue.
The project included two main analysis phases:
- Analyzing the as-built structural arrangement.
- Evaluating recommended structural modifications.
Simplifying the Rudder Horn Casting Model
To produce the finite element mesh for the rudder horn casting, the provided geometry model needed simplification. This simplified version was incorporated into the finite element model (FEM) geometry. The rudder stock was constrained at the upper end using a rigid element to simulate the constraints of the vane axial steering system and its foundation.
Analysis and Findings
The FEA revealed stress concentrations at specific locations aligned with observed failures on the ship. High stress areas were found, where cracks had formed in the rudder horn casting and the surrounding ship structure. By running multiple FEA simulations, modifications were tested to reduce stress magnitudes in these critical areas.
Recommended Structural Modifications
Following discussions with Algoma and multiple FEA simulations, several structural modifications were proposed:
- New 30mm Insert Plates at Frame 0 (port and starboard).
- New 40mm Longitudinal Plates (port and starboard).
- New 40mm Transverse Plates at Frame 0.5 (port and starboard).
- New 20mm Brackets between Frame 1 and Frame 2 (port and starboard).
Incorporating these modifications showed a significant reduction in stress on the rudder horn casting and the surrounding ship structure, with stress reductions ranging from 30% to 60%.
Based on the analysis, it is recommended that the structural modifications illustrated in Reference 7 (to the right) be implemented on the vessel to prevent future structural failures and ensure safe and efficient operations.
NETSCo’s Finite Element Analyses of the ship’s rudder horn identified critical stress concentrations in areas where structural failures were observed. The FEA results demonstrated that under the pintle bearing load, stresses in these areas approached or exceeded the material yield stress. Proposed structural modifications, significantly reduced these stress concentrations, thereby enhancing the structural integrity of the vessel.
This case study highlights the importance of FEA in identifying and mitigating structural issues in marine vessels, showcasing NETSCo’s expertise in providing practical and effective solutions in the maritime industry.
