In the highly competitive environment of today’s space industry, the requirements for vibration qualification testing are becoming increasingly stringent. Smaller test margins and shrinking budgets raise the bar for verification tests on space launch vehicles. In light of these evolutions, EADS Space Transportation recently upgraded and expanded its existing LMS environmental test system to LMS Test.Lab. The LMS Test.Lab software suite supports different testing disciplines, ranging from vibration and acoustic qualification testing to modal testing and analysis. It offers high accuracy standards that guarantee maximum confidence in the acquired data, and its integrated vibration control features protect critical specimens from receiving permanent damage. Another key driver for EADS is the capability of the system to achieve productivity gains in all steps of the test process, from modal pre-tests and instrumentation up to fast and customizable reporting. In addition, the new environmental test solution is deployable as one large test configuration with a high channel count, or as multiple smaller setups operating in parallel.
Under the umbrella of the European Aeronautic Defense and Space organization, in short EADS, a number of world-class daughter companies are united. The group’s activities range from commercial passenger jets (Airbus), helicopters (Eurocopter), military transport planes and combat aircrafts up to launch vehicles, and satellites through its Astrium subsidiary. The EADS Space division is active in all aspects of today’s space industry. Within this division, the Space Transportation subsidiary carries full design and development responsibility for space launchers and infrastructure. Widely known in this regard is its status of prime industrial contractor for the Ariane launcher, and its participation to different sections of the International Space Station (ISS) program. Next to the leading involvement in Columbus, a manned ISS module for zero-gravity research, it develops and manufactures unmanned Automated Transfer Vehicles (ATVs), to be used for regular transportation of supplies to ISS.
A leading European test center for launch vehicles
The reflector of the Apstar VI satellite on the 220 kN shaker,with a square slip table of 12.7 m and a 2 inch stroke.To thoroughly test launch vehicles and related infrastructure under extreme operating conditions, EADS Space Transportation uses complete and all-round testing laboratories. Engineers perform climatic, thermal and pyrotechnic shock tests as well as tests under varying athmospheric pressures in order to examine the static and dynamic performance of launcher subsystem and
components. Also large-scale environmental tests are executed to qualify and validate complete launcher systems. During such tests, launcher assemblies are put on a shaker or in a reverberant room and are subjected to very specific vibration or acoustic loads. To obtain the characteristics of the tested assembly in real-time, hundreds of transducer signals are measured and processed in parallel, using highly efficient data reduction techniques. During ever limited time slots, higher volumes of response information needs to be gathered accurately and well-organized reports delivered in a timely fashion, while safeguarding mission-critical specimen from receiving permanent damage. To strengthen its competitive position in environmental testing and to help realize the aimed 30% overall productivity gain on total launch costs, EADS Space Transportation decided to upgrade its existing LMS test system to LMS Test.Lab. For the site in Bordeaux, the agreement stipulates the installation of a vibration control station and a 540 channel acquisition and analysis station. Both stations are standardized on LMS SCADAS III hardware, and run the LMS Test.Lab software suite. LVD SCSI optic cables connect the front-end racks with the equipment in the control room.
Higher precision testing in a shorter time frame
Cover shield of ISS Columbus laboratory module fully instrumented for environmental testing.Already during the pre-test phase, the environmental test system makes itself useful by performing modal tests and analyses in order to identify the optimal measurement locations on the structure under test. This enables to identify weak points up-front, and to adjust the instrumentation of the actual qualification test accordingly. LMS Test.Lab also automates to a large extent the physical instrumentation of the hundreds of sensors. It supports TEDS transducers, from which it automatically receives serial number, calibration date, x,y,z measurement directions and sensitivities. The new front-end systems acquire the measurement data using 24-bit technology, and highly efficient data-reduction techniques enable massively incoming data to be handled easily and accurately in real-time. LMS Test.Lab controls the data flow and has the capacity to run a variety of tests serving different purposes.
Jean-Pierre Souyri, Manager of the Vibration Testing Section at EADS in Bordeaux, explains: “EADS executes vibration and acoustic environmental tests for final validation and qualification of components, subsystems and full launcher systems, and to update and validate virtual simulation models from the CAE division. As operating margins are often too small to fully rely on virtual simulation, additional tests are requested to perform in-between validations of design options. We are actually able to check specific assumptions made or parameters set in structural simulation models during the ongoing development process. This positively influences the quality of the development and shortens its duration. From specialists as well as novices, we received positive feedback regarding the usability of LMS Test.Lab. They are particularly in favor of the operator workbooks, which guide them through all sequential steps of the test process. By forcing them to check and validate all the important parameters before moving to the next step, the process becomes more efficient and leaves less room for error.”
Testing productivity is also leveraged by the LMS SCADAS III front-ends, which can easily be deployed in any test configuration, regardless of the application the system is being set up for. Arnaud Trimouille, Responsible for Vibration Testing Measurement explains: “EADS selected a system with a reliable and scalable hardware platform. LMS SCADAS III offers high-bandwidth channels, with low noise distortion and phaseshift characteristics, which guarantee top-class measurement accuracy. At the same time, LMS SCADAS III is scalable hardware, which allows us to anticipate future needs and to have the system adapted accordingly. At least as important as expanding channel count is the modularity of the system, which enables to create two up to five smaller independent test setups that can run in parallel at different locations. Especially when dealing with a number of tests on smaller subassemblies, it is much more efficient to use a system that can perform the tests simultaneously. In most of the parallel setups, the vibration control and data acquisition functions are combined to be able to drive and control the shaker system fully independently. Housing these essential functions in one system increases the efficiency and maintainability of the complete system, and improves the security of expensive launcher assemblies. The closed-loop vibration control is monitored accurately and consistently, and avoids specimens to be over-tested or receive damage in any other way.”
Fast and flexible reporting increase test productivity
Huygens probe, which is currently nearing Saturn’s moon Titan after a 7 year journey, shown during vibration qualification testing.At any moment during the execution of an environmental test, LMS Test.Lab can monitor any measurement or control signal on the display. The operator is immediately notified about signals exceeding thresholds, while remaining in full control of the test setup. With a remote control keyboard at hand, the operator can access the most important on-line functions while standing next to the structure being tested, and can, if needed, abort the test with a single push on a button. Under any circumstances, all the acquired data is safely and securely stored. At the end of the cycle, shortly after receiving the analysis results, environmental test reports become available. LMS Test.Lab quickly generates reports that provide maximum leverage at the end of the test, usually when time pressure is highest. Batch reporting, active picture capabilities and the tight integration with Microsoft Office are among the reporting aspects EADS engineers appreciate most. EADS requires no standard reports, since most of the executed tests have a very specific character. The flexibility towards the definition of report content enables engineers to manually put together the desired graphs from the multitude of available data.
The new LMS Test.Lab environmental test system of EADS is in accordance with the management policy of optimizing the number and variety of test systems. Jean-Pierre Souyri clarifies, “The LMS SCADAS III hardware and LMS Test.Lab software platforms, which form the core of our test system of choice, are responsible for the system’s favorable scalability, modularity and security aspects. EADS believes that standardizing on a limited number of such platforms increases productivity in all steps of launcher qualification testing. Other decisive factors are the system’s integrated vibration control and extended scope of applications and analyses, in our case covering the vibration, acoustic and modal fields. EADS feels it is a complete product, and is also satisfied with the prompt technical support offered by LMS France and LMS Headquarters. In the future, EADS targets to intensify the collaboration between Test and CAE, and expects to further increase channel count to gather even more information during one test, and to fulfill higher precision needs.”
