SBIR-STTR Award

Innovative Approach to Full Scale Fatigue Testing using Hybrid Methodologies
Award last edited on: 11/16/2018

Sponsored Program
SBIR
Awarding Agency
DOD : Navy
Total Award Amount
$724,936
Award Phase
2
Solicitation Topic Code
N171-027
Principal Investigator
Chang-Hee Hong

Company Information

Technical Data Analysis Inc (AKA: TDA)

3190 Fairview Park Drive Suite 650
Falls Church, VA 22042
   (703) 237-1300
   tdainfo@tda-i.com
   www.tda-i.com
Location: Multiple
Congr. District: 08
County: Fairfax

Phase I

Contract Number: N68335-17-C-0343
Start Date: 4/21/2017    Completed: 7/26/2018
Phase I year
2017
Phase I Amount
$224,949
We address main issues concerning full-scale airframe test in a systematic way by means of tests and analysis tool development. Our tests will start with idealized component testing subjected to multi-axial loading with and without HCF content to assess impact of HCF on failure initiation points and failure modes. We then build test setup for a reduced model airframe substructure testing using advanced hardware, sensor technology, and data acquisition systems. We also propose developing the kinematic model of the test set up above to optimize the location of the loading and sensing points and minimize the number of actuators and sensor used. We plan to carry out the test using a load spectrum appropriately scaled to the test article and capture data from the test using advanced technology. We develop high fidelity tools for spectrum editing to support accelerated testing without incurring alternate failure points and modes and damage, and multi-axial tools for test data analysis as well as predicting life limits and inspection intervals of service aircraft structure. Based on these proposed tests and analysis efforts, we will develop concrete plans for full-scale airframe testing.

Benefit:
The benefits coming out of our planned research effort will reduce the total ownership cost to the rotorcraft operators as well as OEMs. The rotorcraft owners and operators such as Navy and other agencies will see a huge benefit as our test method and technology will provide them guidelines for establishing a satisfactory economic life of airframe structural elements without major repair while assuring probability of major catastrophe from fatigue failure is

Keywords:
wavelet transform for spectrum editing, wavelet transform for spectrum editing, LCF and HCF loading, substructure testing, Load interaction effect, Rotorcraft airframe testing, multi-axial loading and analysis, 6-DOF testing system, vibratory loads

Phase II

Contract Number: N68335-19-C-0009
Start Date: 11/1/2018    Completed: 5/12/2020
Phase II year
2019
Phase II Amount
$499,987
Targeting our overall SBIR objectives of (a) developing concepts for airframe full-scale fatigue testing utilizing the latest advancements in test hardware and sensor technology to correctly impart low and high frequency loads and capture data with high fidelity, and (b) demonstrating such a concept by building and testing reduced model substructure of airframe, we build upon Phase I effort on an initial 3-DOF test system set up and preliminary tests. Continuing our initial Phase I effort testing using 3-DOF test set up on an idealized structure, we propose to achieve in Phase II (a) completion of tests of the idealized structure using 3-DOF system and (b) conduct tests on a non-idealized structure, either by reconfiguring the 3-DOF test rig or by designing and building a completely a new 6-DOF test system. These efforts will provide a solid platform to develop a complete test of rotorcraft major airframe substructure.

Benefit:
The main product of this research and development will be a hybrid fatigue testing system with the capability of more accurately loading the full-scale aircraft test article for both HCF and LCF, which is necessary to accurately assess fatigue and durability of aircraft structures. This mixed mode testing methodology, with many advanced technologies incorporated, are verified by the idealized test frame and the reduced scale subcomponent test frame, built and tested in Phase I and Phase II, respectively. The hybrid fatigue testing methodology developed will enable new platform developers to accurately substantiate fatigue lives and durability of newer platforms such as the current Joint Military Rotorcraft (JMR) program. For existing aircraft already in service, the hybrid fatigue testing methodology with advanced technologies and software packages implemented will provide OEMs and aircraft operators unique opportunities for substantiating fatigue lives and durability of many airframe components currently in service. Our research has confirmed that many of the previous airframe tests did not include the HCF loading conditions. Hence, it is expected that many of the existing aircraft in service may have numerous fatigue cracking issues due to the unaccounted mixed mode loadings conditions during the substantiation of their airframe fatigue lives. Therefore, all rotorcraft platforms will benefit by the use of the developed technology. In addition, use and application of the hybrid fatigue testing system is not only limited to aircraft industry. This technology will be useful to other industry sectors such as engine manufacturers, automotive, ship, wind turbines, and heavy machinery to assess the performance and remaining useful life of their critical components. Two platform development programs, the CH-53K and JMR, will be the first two candidates TDA will pursue to propose to use the developed hybrid testing methodology for their FSFT. Other helicopter platforms flown by, the Army and Navy, and their OEMs will also be approached by TDA to introduce the developed methodology to re-substantiate fatigue lives of airframe components for their major fleets (i.e., MH-60s and AH-1Z/UH-1Y) to improve the safety of aircraft and reduce the overall fleet maintenance cost.

Keywords:
Load Actuators, idealized and non-idealized structure testing, 3-DOF test system, Rotorcraft Airframe Fatigue Testing, digital strain imaging, Hybrid Fatigue Testing System, Mixed Mode Fatigue Testing of Scaled Airframe Components, 6-DOF test system