Aircraft structural design and analysis

High expectations: airframe structural design for the aircraft of the future

1.04 billion tons of CO₂: that’s the estimation of aviation emissions in 2018.¹

Indeed, within all means of transport, aviation accounts for most of the CO₂ emissions and non-CO₂ emissions per km traveled. With the current trends, the sector needs a drastic change. However, turning toward sustainable aviation is not that easy for aircraft manufacturers and an optimal aircraft structural design is required more than ever.

Over the last decades, engineers have perfected aircraft structural designs based on kerosene-powered engines. To achieve a cleaner propulsion system, the improvements done in the past are meant to undergo new challenges.

As an engineer, your role today is to understand the adjustments required in your aircraft structural design processes to meet the sustainable aviation goal.

Various aeronautic actors have been taking action toward this new perspective. We have seen some promising trials and test flights of electric vertical take-off and landing (eVTOL) aircraft with distributed electric propulsion (DEP).

Yet, to meet sustainable aviation requirements, conventional aircraft must endure more architectural and system modifications. Recent electric aircraft trials have had positive outcomes, but also pointed out considerable areas of improvement in aircraft design, such as:

• Battery performance
• Weight optimization
• Aircraft structural design and analysis
• Airworthiness
• Wing configuration

You must adapt the characteristics of these elements for your aircraft to reach successful physical testing. The current aircraft structural design does not take advantage of the potential offered by new energy vectors and propulsion systems. The most cost-effective way to achieve an optimal aircraft structural design is to analyze data through a high-fidelity digital twin approach.

Integrated aircraft structural design and analysis approach

The timely and cost-effective certification of new aircraft has relied heavily on historical knowledge of the last decennia, improving incrementally from aircraft to aircraft.

The transformation to a more sustainable way of flying requires innovation at a level to which the certification process has historically not been adopted. Safety and sustainability have become competing paradigms. Digitalizing the certification process, frontloading simulations to capture failure modes early on and de-risk the design, and using simulation to test more efficiently offer a way out.

Digital processes bring together design, flight physics, dynamics, stress and fatigue simulation and test teams in a way that was previously not possible. More designs can be evaluated, loads are available earlier and the loops between flight physics and structural design teams run more efficiently.

Can historical designs be bridged with contemporary standards?

Historical aircraft structural designs can indeed be aligned with contemporary standards through the use of advanced aerospace engineering software. AeroFEM, a renowned Swiss engineering firm specializing in aviation projects, undertook an ambitious endeavor to prove the airworthiness of a modern-day replica of the legendary Junkers Ju 52. To achieve this, they harnessed the cutting-edge technology provided by Simcenter aerospace engineering software.

The Junkers Ju 52, an iconic aircraft that took flight for the first time in 1932, quickly gained a reputation for its unmatched reliability. AeroFEM’s primary objectives were to reduce the aircraft’s take-off weight to meet certification standards, reconstruct the aircraft using new scans and existing models, and replace original materials with contemporary alternatives.

For comprehensive aerodynamic and aircraft structural design and analysis, AeroFEM utilized Simcenter fluids and thermal and mechanical solutions. These tools provided valuable insights into the engineering behind the original Ju 52 design.

According to Danny Wadewitz, AeroFEM Analysis Engineer and Executive Board Member “Using Simcenter STAR-CCM+, we put the geometry we obtained from reverse engineering into a CFD analysis. We then used the results from the CFD analysis to provide the boundary conditions in Simcenter Femap for FEA analysis. This gave us the internal loads on every truss of the aircraft”.

With Simcenter engineering software, aerospace companies can drive productivity, achieve better designs faster, and ensure successful program outcomes.

References

¹ Climate change and flying: what share of global CO2 emissions come from aviation?, Hannah Ritchie, 2020.