Collins Aerospace

Validate and update the stress analysis tools used by In-Service Stress Engineers to evaluate landing gear structural integrity after abnormal incidents.

The NASTRAN Beam Models are validated for accuracy and practicality and integrated into the legacy In-Service Engineering (ISE) Tool for seamless integration.

The tool has been updated to address software bugs, improve analysis methodology, and enhance user experience.

The tool is optimized for handling complex calculations and extensive data and can integrate any future beam model cases.

Consistency in results between SEAS 200 and NASTRAN models is maintained during validation, and the tool undergoes rigorous testing for accuracy and reliability.

Training and support is provided for in-service stress engineers.

COMPLETED

The NASTRAN Beam models were successfully validated and integrated with the new version of the legacy tool.

Tasks included collecting data on past hard-landing incidents, documenting loading conditions, and providing this summary presentation.

The Legacy ISE Tool has been updated with tasks including user feedback, initial review, and QoL changes.

The final testing and verification of the updated tool is done.

Enhanced Accuracy in structural Integrity Assessments:

NASTRAN Beam Model Validation: The successful validation of NASTRAN beam models ensures more accurate assessments of landing gear integrity following in-service incidents outside the design envelope..

Improved Decision-Making for Aircraft Maintenance:

Legacy ISE Tool Updates: Incorporating the updated beam models and user feedback into the Legacy ISE Tool allows engineers to make more informed decisions regarding the maintenance and repair of landing gear systems.

Increased Efficiency in Incident Analysis:

Streamlined Workflow: The improvements made to the Legacy ISE Tool, including Quality of Life changes and error fixes, streamline the workflow for In-Service Stress Engineers.

Higher Safety Standards:

Accurate Margin of Safety Calculations: By ensuring accurate calculations of internal loads and margins of safety, the project maintains a higher level of safety standards per normal industry requirements.

Continuous Improvement:

Integration of Advanced Models: The successful integration of validated NASTRAN beam models into the Legacy ISE Tool represents a continuous improvement in stress analysis methodologies.

Implement a transformation tool capable of transforming loads from the deformed local coordinate system back to the undeformed local coordinate system.

Compare SEAS200 results to Nastran results in an undeformed local coordinate system.

Project Category: Continuous Improvement / Obsolescence Management

The project is a continuation of a previous conversion of existing landing gear SEAS200 beam models into Nastran Beam Models.

SEAS200 is becoming obsolete and may not have support in the future.

The purpose is to validate the existing landing gear Nastran beam models for future hard landing analysis.

COMPLETED

The focus when comparing the SEAS200 results with the transformed Nastran results has been on the components that make up the resultant force.

When comparing results, percentages can be deceiving, attention should be put on the magnitudes that generate such percent differences.

Correlation is a minor improvement compared to previous results. Further investigation is required to determine the cause of the difference.

Project 1: SSD Creation

The goal of this project was to createand release Structural Substantiation Documents (SSDs) to summarize the one or more design changes made to a regional aircraft's landing gear components after their initial approval.

DSS documents provide the analysis of one specific aspect of a given component.

SSDs are composed of summaries of Design Study Summary (DSS) documents for a given component.

Project 2: Bushing Migration Study

The purpose of the study is to use hand calculations to determine if the holding force on the MLG bushing is large enough to withstand the ejection force experienced by the bushing due to external axial loads from the axle.

The data sourced included data pertaining to bushing and bogie beam dimensions, elastic moduli, operation temperature, and friction coefficients.

Pressures are calculated, then the holding force can be found using the pressure and area values. The ejection force values are found via reaction forces.

COMPLETED

To establish a correlation between variation in lug dimensional parameters and the stress behaviors at the lug lubrication holes.

Conducted FEA, classical analysis to develop stress prediction curves that allow for quick assessment and evaluation during lugs rework process

Developed a parametric tool in VBA and Pyhton to accelerate the analysis process for recurring lug repairs

Created detailed engineering report including all analysis iterations, FEA results, and correlation

COMPLETED

The obtained stress prediction curves provide valuable insights into how dimensional variations of lugs influence stress patterns at lubrication holes, thereby facilitating more efficient structural analysis and lug rework processes.

The developed parametric tool can be utilized to speed up the analysis process for recurring lug repairs.

Developed tools to aid in the static analysis of threaded joints that experience combined axial load and moment.

Became familiar with the method of analysis already developed by FEA of a detailed threaded joint to incorporate a moment effect into standard thread analysis.

Performed FEA for the threaded joint of interest for a series of joint geometries and load cases.

Used FEA results to develop a relationship between the critical length parameter and joint geometry.

Threads subjected to axial load and moment develop a non-uniform axial load distribution.

A revised analysis method was developed to account for moments in the analysis of threads.

Standard practices for the calculation of the critical length parameter were updated using FEA results, although this method was found to be time- consuming and prone to user error.

COMPLETED

Successful use of Excel and scripting tools to automate the revised method of thread analysis. 

Replicated the previous results using new tools, documenting revised methods of analysis.

Applied the new methods of analysis on a different threaded joint in the landing gear, obtaining accurate results and validating the functionality of automation tools developed.