Aircraft Sustainment, Structural Health Monitoring

Critical Materials

Aircraft Sustainment

Fleet managers are increasingly challenged to keep aircraft flying longer, into untested operational conditions. Usage Monitoring Programs allow for real operational data to be gathered, verifying platform safety and continued airworthiness. Usage Monitoring Programs include:

OLM - Operational Loads Monitoring

SHM – Structural Health Monitoring

Rotorcraft HUMSmore

iVHM – integrated Vehicle Health Management

Fleet managers with early access to a complete usage monitoring solution, are able to remove implementation delays and achieve return on investment years in ahead of schedule. This is made possible with CRITICAL Materials SA flexible integrated solutions with our expert partners who complete our offer.

OLM - Operational Loads Monitoring

Fleet Operators that instrument their aircraft with loads monitoring equipment are able to determine the remaining structural life of their fleets, often achieving

10%-20% life extension beyond the original design life

>50% reduction in scheduled maintenance

CRITICAL Materials provides PRODDIA©AERO 2.5 as loads analysis platform to aircraft sustainment programs our solution is highly reliable and works with any COTS hardware solution of sensors and data acquisition systems.

The aim of a loads monitoring program is to make better predications about the useful life of an aircraft, and particularly metal structural components as they are subjected to normal operational regimes. These programs are often labelled OLM (operational loads monitoring), ODR (operational data recording) or L/ESS (loads/environmental spectral survey). A loads monitoring system in its simplest form is seeking to count the number and strength of loading cycles that a component is experiencing. This can be done using a combination of accelerometers measuring G levels and strain gauges measuring strains, both arriving at a loads profile in different ways.

More generally the data acquired during a loads monitoring campaign can be used to correct the conservative loading assumptions in place during the design phase. The actual operational loading assumptions will allow ground-based analysis based on PRODDIA©AERO 2.5 to arrive at more realistic life estimates.

SHM – Structural Health Management

Aircraft maintainers and operators who use Structural Health Monitoring (SHM) systems are able to determine if structural damage has occurred, when the damage event occurred and precisely where the damage is located.  A SHM system feeds into a Condition Based Maintenance (CBM) regime, where aircraft maintainers can efficiently direct their resources towards the aircraft that actually require repair, the result is less overall maintenance effort and increased aircraft availability. CRITICAL Materials SA provides PRODDIA©AERO 2.5 as an SHM platform for who require flexible, high fidelity structural health analysis.

SHM systems aim to monitor aircraft components in near real-time and detect structural defects when they happen. Rather than just reporting loading cycles on structural components, a SHM system will report actual changes in structural components.

SHM techniques have been used for many years on the ground for aircraft inspection and overhaul. The terms NDT or NDI (non-destructive test or inspection) are typically used in this context. SHM is becoming important for new composite airframes where traditional metal fatigue models are not useful and where damage is often not apparent at the surface.

Our SHM solutions do not rely on bulky NDI equipment and techniques, but rather use a minimized number of low-cost sensors to guarantee a specified POD (probability of detection), e.g. 12 accelerometers optimally distributed on a wing-surface to guarantee detection of defects with surface area >1cm2.

HUMS – Health and Usage Monitoring System

Helicopter Fleet Managers use Health & Usage Monitoring Systems (HUMS) to monitor critical rotational components within transmissions and drive trains. The condition of each component is monitored in near real-time and fault indications are fed into a Condition Based Maintenance (CBM) system; an effective CBM system ensures that damaged components are replaced in the short window between detection and failure. The likelihood of a critical component failure during flight is reduced by 10-fold when a helicopter has a HUMS system on-board.

Health & Usage Monitoring systems were first developed in the aftermath of several Northsea helicopter crashes in the 1980s and a US presidential Blackhawk crash in 1991. In the aerospace industry HUMS almost always refers to a helicopter transmission/gearbox/rotor monitoring system. The association is so strong that the “H” could almost stand for Helicopter. HUMS has had a profound effect on rotorcraft safety with technical accidents decreasing 10 fold upon their introduction (D. A. Howson, “Offshore Helicopter Safety”, Civil Aviation Authority, Reported May 2013).

One critical part of a HUMS system are the set of algorithms that analyze the vibrational/tacho condition indicators and access the health of the rotational unit being monitored. Another critical part of a HUMS system is the set of procedures that ensure that health assessments are translated into maintenance actions. CRITICAL Materials SA provides PRODDIA©AERO 2.5 that can provide accurate data driven analysis for HUMS systems providing state of art diagnosis and prognosis results.

iVHM – Integrated Vehicle Health Management

Modern vehicle platforms often contain multiple health managements systems, each providing a separate prognostic or diagnostic assessments for different aircraft subsystems. Aircraft integrators are increasingly seeking ways of integrating multiple health management systems in an automated way, these Integrated Vehicle Health Management (iVHM) systems remove the capacity for human error and delays, with all assessments feeding directly into Maintenance scheduling systems.

iVHM is a modern concept that seeks to automate and integrate hardware and software components of one or more vehicle health management systems, to provide maintenance and logistical systems with a global picture of the vehicle health and give direction on how the vehicle and fleet should be managed for optimum health.

An iVHM system will typically manage several health and prognostic assessment system such as OLM (operational loads monitoring), SHM (structural Health Monitoring), EM (Engine Monitoring), integrating the outputs automatically and creating a global advisory.

All the stages of an iVHM system are automated, there should be minimal human interaction required to facilitate data and information transfer. Human operators should only need to interact with the external systems, e.g. cockpit warning lights or maintenance ERP system. CRITICAL Materials SA provides PRODDIA© Framework 2.5 that can provide an integration environment for the deployment of scalable iVHM systems for any type of platform (unmanned/manned rotary or fixed wing platforms).less


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Critical Materials
Headquarters and Technical Center: SPINPARK Building
4805 017, Guimarães

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