https://simcompanion.hexagon.com/customers/s/article/MSC-Apex

• Automatic Multi-level Static Reduction (AMSR): A brand-new unique method for static reductions for external super elements and external modules result in up to10x faster speeds without compromising accuracy
• Symmetry constraints in topometry optimisation
• A new high-performance nonlinear solver in SOL 400 (NLPERF):
  • Performance improvements: New DMAP flow, MUMPS solver and parallel scaling up to 32 cores
  • Convergence monitoring for tracking the job status, iteration file (.itr) and GUI monitor
  • Friction convergence check in node-to-segment contact, arc-length method in contact problems

• Out-of-core (OOC) capability and Distributed Memory Parallel (DMP) options for the MUMPS solver
• Reduce disk space requirements and achieve faster solution times for models with poroelastic materials (PEM) using compressed Reduced Impedance Matrices (RIM)
• Reduce runtimes for linear static problems with a large number of load cases

• Easy job setup and submission for Transfer Path Analysis (TPA) using the new Single-Step TPA capability
• Model glue lines using cohesive elements in linear solution sequences to easily perform linear analyses of complex nonlinear models
• SOL 128 post-processing improvements include the ability to output iterative outputs for displacements and nonlinear loads in CSV format as well as the ability to obtain outputs for selected output frequencies

• External super elements and residual vectors are now supported in real coupled modes with improved performance
• Append results to existing hdf5 files to allow for tracing and grouping of multiple runs of each modular component through a single file
• The MDSET case control command allows you to select specific modules for data recovery when there are duplicate elements or grid IDs across modules
• The PEAKOUT capability is extended for Equivalent Radiated Power (ERP) at peak frequencies
• Include fluid modes for acoustic grids in the modal neutral file (.mnf) to facilitate to recover acoustic pressure directly in Adams
• Include rotodynamic effects in the modal neutral file (.mnf) to capture rotodynamic effects in Adams
• New enhanced job summary in the .log file

Published: July 15, 2024 2.26pm SAST by Edward C. Smith

Distinguished Professor of Aerospace Engineering, Director: Vertical Lift Research Center of Excellence, Penn State

Helicopters draw a lot of attention with their almost magical ability to hover, fly in any direction and operate without runways. They also help save many lives, often dramatically, with their extensive use in all-weather military missions, ambulance duties and search-and-rescue roles.

When things go wrong, dramatic images and news stories about helicopter accidents grab the public’s attention. This is especially true when high-profile celebrities or government officials are involved.

However, modern rotorcraft are safe. Each year, the U.S. commercial helicopter industry flies about 3 million flight hours. There were 0.77 fatal accidents per 100,000 flight hours on average from 2018 to 2022. In comparison, general aviation, which refers to small fixed-wing aircraft and not jetliners, averaged 0.88 fatal accidents per 100,000 flight hours over the same period.

As an aeronautical engineer who specializes in rotorcraft and the director of a national vertical lift center of excellence, I have observed academic, government and industry efforts to improve helicopter safety. A lot of technology and training have gone into making helicopters safe.

Long road to safety

Rotary-wing aircraft were first developed over a century ago. The first that went into mass production was the autogiro, developed in 1923 by Juan de la Cierva in Spain. The pinwheel-like nature of the main lifting rotor avoided the dangers of stalling, which wrecked so many fixed-wing aircraft during that era. Stalling is when the angle of an airplane’s wings relative to the airflow is too great, causing the plane to lose lift.

Within 15 years, the first true helicopters with powered rotors – capable of hovering, low-speed flight and safe descent in the event of engine failure – were in the air in both Europe and the United States. Large-scale military and commercial production began just a few years later during the World War II.

How helicopters fly.

Today’s helicopter operations are anchored on three main principles: comprehensive vehicle design, testing and manufacturing; well-trained flight crews; and thorough maintenance practices. Advanced technology plays a vital role in each of these pillars of helicopter safety.

Safety fundamentals

Helicopter safety begins with the fundamental capability of large-diameter rotors that can auto-rotate in the event of engine failure. With the engine off, the rotors spin freely, slowing the helicopter’s decent and allowing parachute-like controlled landing. Reliable powertrains – engines, gear boxes and driveshafts – long-lived blades and low-vibration airframes have also paved the way for safer flights.

Additionally, advanced autopilot and computer-controlled or assisted flight controls, terrain-avoidance radar and rotor blade deicing systems that enable all-weather flight have become common on modern helicopters. Decades of basic and applied research conducted in university, government and industry laboratories has yielded many advanced technologies. Today’s helicopters typically have radar- and lidar-based collision avoidance systems, comprehensive digital terrain mapping databases and adaptive controls that help the pilot feel differences depending on flight conditions and aircraft characteristics such as payload.

Rotorcraft do require specialized pilot training to master. Pilots often train on fixed-wing aircraft before transitioning to rotary-wing vehicles, much as you might learn to ride a bicycle before taking on a unicycle. Pilots spend many additional hours or even years of flight instruction to earn a helicopter license.

A British pilot trains in a helicopter simulator. Defence Imagery/Flickr, CC BY-NC-ND

Rotorcraft inherently feature more moving parts than fixed-wing aircraft, which makes careful design of bearings, gearboxes, shock absorbers, lubrication systems and other mechanical components critical. As with pilots, helicopter mechanics need additional training hours and skill sets.

Indeed, for some complex military and rescue missions, mechanics fly along as integral members of the flight crew. These flight mechanics closely monitor critical systems using onboard temperature, vibration, noise and metal chip sensors, and can even troubleshoot and repair many mechanical, electrical and digital issues that arise.

Advanced sensors and computer software make maintaining helicopters quicker and more thorough. Additionally, advanced design and manufacturing methods for rugged composite materials and specialized flexible polymers have dramatically improved the durability of dynamic components such as blades and rotors.

Risks remain

Even with all the advanced design, training and technology in place, accidents happen. The vast majority involve a complex chain of events. Pilot or mechanic error, typically associated with unusual circumstances, is a primary cause of many crashes.

Bad weather often contributes. Many essential flight operations such as search and rescue, firefighting and military transport necessarily occur in sandy, snowy, smoky or stormy environments. These “edge of the envelope” conditions raise the risk factor, despite the best technology and training doctrines. Even the intense and realistic training exercises for these missions can be inherently more dangerous than standard flight.

John Goglia, a former member of the National Transportation Safety Board, explains safety factors of helicopters in light of high-profile crashes.

Advanced technologies

New technologies continue to improve flight safety under these difficult conditions. These include more effective, reliable and lower power rotor blade deicing or anti-icing systems; improved weather forecasting models; and even onboard ice-cloud detection systems. Researchers are developing artificial intelligence-enabled expert systems that help pilots decide when and if it’s safe to fly.

I expect advanced technologies to enable reliability and safety statistics to continue to improve, and operating costs to drop, as thousands of aerospace engineers around the world bring life-saving, time-saving and security-enhancing improvements to these remarkable vehicles.