Testing Reality in an Increasingly Complex Design Space

Digital simulation tools have transformed the designing and testing of new aircraft, as well as the way they are manufactured and sustained.

The universal adoption of digital 3-D design tools has truly changed forever the way that advanced products are created, from original concept studies, development, testing, and manufacturing, right through the lifecycle to maintainability, future enhancement, and long-term support. The ability to share detailed specifications and test data between all partners worldwide, but with controlled access as required throughout the supply chain, enables large and small suppliers to work to common standards and requirements, maintaining the same data accuracy across the network. This has not only saved valuable time, helping to reduce costs, but has brought about higher standards of product quality and, importantly, more traceability, providing a clear picture for project managers who have access in real time to progress at all levels.

Such has been the rapid rate of progress in all aspects of 3-D simulation technology it is hard to believe that its widespread adoption only dates back to the 1980s. The most commercially successful pioneer of digital design tools, originally known as computer-aided design and computer-aided manufacturing (CAD/CAM), arrived in the form of the CATIA product line, from Dassault Systèmes. This was a significant breakthrough technology and enabled the aerospace, defense, and automotive sectors in particular to use digital tools to transform the way new products were designed and made.

Before long the obvious advantages of using CAD/CAM methodologies cascaded into every area of manufacturing, as it reduced much uncertainty in complex manufacturing programs and speeded up the process in an ever increasing number of specialist activities. Initially it was seen as a way of eliminating the need for huge numbers of detailed design drawings, which then had to be checked before distributing, and which took more time to modify and then re-check.

CATIA Version 3 introduced a 3-D design capability in 1986 and by 1994, V4 had introduced the more advanced digital mock-up capability. In 1999 V5 introduced a 3-D/ product-lifecycle management tool. A decade later, V6 introduced the Dassault Systèmes 3DEXPERIENCE platform that has gone on to power brand applications serving 12 industries and a wide portfolio of industry solutions.

Across Scope and Scale

CATIA Version 6 screen image showing how the operator can access the fuel system in its entirety within a 3-D model of the aircraft. (Dassault)
At the opposite end of the scale from multi-billion dollar civil air transports and military programs is the around-the-world record-breaking solar-powered Solar Impulse airplane, which used the 3DEXPERIENCE platform for design and assembly simulation. This permitted the design team of about 50 project engineers to determine the best configuration to adopt in terms of weight and size and cockpit design, as well as how best to assemble the final design, and even how to transport it safely to the initial take-off location.

This project was very complex, involving a combination of new energy and propulsion systems, with a new lightweight airframe. Each element was designed and tested using simulation techniques, with no physical mock-ups. CATIA was used for designing all the individual parts and for evaluating the assembly before manufacturing took place. Even the plies of the carbon fiber structure were defined and optimized in virtual reality, as were the machined tools used to produce the carbon fiber parts.

All the design, test, and manufacturing data was tracked using the 3DEXPERIENCE platform and thus was easy to validate for total part traceability and certification. Without the ability to design and test the Solar Impulse in this simulated format it would have been impossible to develop the project in an affordable way.

Image of how an assembly workstation or maintenance bay can be configured to support a combat aircraft using advanced 3-D simulation tools to test and validate various automated activities on the aircraft line. (Dassault)
In contrast, the design, development, test, and manufacture of the new Airbus A350XWB wide-body jetliner involved around 4000 people on a daily basis, of which 85% were in the supply chain. By adopting the 3DEXPERIENCE platform, and the ENOVIA tool, employees and suppliers were able to collaborate in real time using a unique digital mock up as a common reference. This integrated all necessary data requirements globally and represented a considerable advance over previous digital simulation solutions that comprised many separate elements.

Cut-away image of an aircraft interior showing how CATIA tools can be used for detailed design. (Dassault)
Changes made by the design office were immediately communicated to those in manufacturing, which dramatically reduced the time needed to prepare the tooling for production. A completely new approach to designing the electrical harness installation was just one example of how the overall assembly process and design quality was improved. Engineers were able to perform realistic non-linear analyses using SIMULIA to predict the strength and behavior of the aircraft’s structure.

The optimized industrialization of the design for the manufacturing and assembly stage was created using DELMIA. As a result of fully exploiting all these digital tools on the whole A350XWB, it is claimed that the assembly process was reduced by 30%.

Minimizing Risk

The task of designing, building, testing, and introducing into service new airplanes has always been a risky business at almost every stage, but especially when introducing new advanced features, as has been seen in recent times with Boeing’s 787, Airbus’s A380, and Bombardier’s C-Series. Attempting to rectify the late discovery of unexpected faults has cost manufacturers dearly in bad publicity, loss of customer confidence, and goodwill, and has also devalued the share price of major partners and their suppliers during the recovery stages.

When problems arise as full-scale production is ramping up, the impact on delivery flow patterns can be enormous. Even using advanced digital design tools does not eliminate all program exposure, especially if the management team underestimates risk factors at key stages during the development and test phases.

A computer screen image showing flutter simulation multiphysics representation with Fluid Structure Interaction on a computer model of a business jet. (Dassault)
The desire to avoid early delays and cost increases by enhancing visibility and traceability through all stages of testing led Dassault to develop Test to Perform, which aims to improve overall integration, verification, and qualification using a single platform that connects all disciplines across the program. Realistic and accurate simulations allow for increased virtual testing throughout the development process, lowering costs compared to physical tests.

A key requirement in keeping a new program on track is the ability to make decisions in a timely manner based on a complete understanding of test results and a correct interpretation of the available data. The Test to Perform solution enables managers to visualize test results in context through a functional digital mock-up that incorporates system behavior and thus tests how functions work with the aid of a more complete, true-to-life design definition. This encourages closer integrated activity between test teams and those in engineering and it gives the whole test community a greater understanding of the test results on which informed decisions can be made.

The overall real-time view of the test activity is comprehensive and performance measures are shared by all. Users automate and execute simulations using high-performance computing systems and manage both the simulations and resulting test data. Using a common collaborative platform reduces the prospect of errors and allows improved performance-based decisions while specifications and compliance with regulations can be met with confidence. The testing of new design concepts at an early stage improves the firmed-up design and shortens the testcycle process and this in turn speeds up validation.

Another advantage of using this solution is that virtual testing can exceed physical test limitations, producing valid data, but at much lower costs and quicker. Using robust digital modelling tools, the likelihood of premature failure is minimized and unforeseen issues can be identified early and corrective changes made and re-tested.

Defending Against Increasing Complexity

3DEXPERIENCE/SIMULIA physics results explorer showing virtual tests being undertaken on the Airbus EFan electrically powered light aircraft design. (Dassault)
One of the main causes of cost escalation is growing complexity as programs progress. Often this is a reflection of launch customer indecision—requirements and subsequent demands can change as other factors evolve, such as market competition or the availability of new technologies and features on rival designs. If customer suggestions are accepted at an early stage it can enhance the marketability of the product, but further down the design path it becomes more of a challenge to adapt the design without introducing unacceptable extra delays and cost.

New military air programs are even more prone to customer interference during the development stage. Electronic systems develop faster than the airframes in which they are carried, and typically can offer major improvements in performance every five years, compared to aircraft enhancements improving perhaps only marginally, every 10-15 years.

As an all-new military air platform can take up to 20 years to reach service, it has become essential to incorporate a systems architecture that will allow for capabilities to be upgraded at regular intervals. Combat air programs are prime examples of where cost escalation due to underestimated system complexity can threaten termination, or procurement reductions, and so the need to break this damaging spiral is more important than ever if future programs are to remain affordable and deliverable within a realistic timescale.

Dassault has identified reducing complexity in program management as an important goal in helping companies lower both non-recurring and recurring program costs. The required efficiencies include shortening the design time and introducing simplified manufacturing with, for example, fewer component and structural parts. But cutting a swath through the labyrinth of conventional multi-level design reviews and audits and replacing these arrangements with a coordinated enabling, transparent, integrated digital solution represents a very necessary measure to retain a firm grip on the wider program.

In conjunction with Dassault’s 3DEXPERIENCE platform and Co-Design to Target solution, stakeholders can stay appraised of a program’s status in real time so that any emerging issues can be seen and addressed at the earliest possible stage. This solution integrates all the engineering works-in-progress with contracts management, program controls, systems engineering, design engineering, configuration management, data management, and subcontracts administration.

The view into the program is always current, promoting a smoother manufacturing ramp up and more efficient production.

Optimized Excellence

There is no reason today why optimized excellence can’t be designed into an aircraft, minimizing the need for redesigns and ensuring the platform will stay on schedule and then have a lengthy lifespan. Co-Design to Target integrates “value streams” to help reduce complexity in the product-development process. This has been needed ever since programs, notably international ones, started to draw in more and more people, at many different locations, in product definition leading to detailed design.

The process involves many thousands of specifications being cascaded through the supply chain covering systems, sub-systems, and components, as well as the activity in the primes. By adopting a leaner development approach, teams collaborate and converge quicker on detailed definition at every level. By using a behavioral digital mock-up, engineering architects can define systems installation and then exhaustively validate the associated installation architecture early on.

Using requirements-based 3-D design can ensure that any installation conflicts are avoided completely and can be used for early system and network checks. Multi-disciplinary simulations help reach performance targets and bring forward product maturity to specification. This can make a real difference to keeping delays and cost increases at bay during the early stages of a program, which reduces the likelihood of having to make penalty payments to delayed customers.

Delivering promised product performance and high reliability is still at the heart of customer expectations. Minimizing development risks and maximizing profitability by seeking ever-greater efficiencies requires companies throughout the aerospace sector to embrace new processes and methodologies enabled by new transformational technologies. Exploiting the latest advanced digital simulation products and services shows a better way of achieving these goals.