Substructure and Component Testing

Background

In recent years there has been a clear trend in structural testing towards using more advanced sub-structural and component testing techniques.

Sub-structural testing is aimed at testing only a part of a full-scale structure with the aim to investigating localized phenomena or the response of only that part of the structure without having to test the entire structure. In the testing of the sub-structure the surrounding structure, loads and supports are mimicked with a configuration of actuators and supports. Thus, sub-structural tests are inherently multi-axial tests, where relations between larger amounts of actuators must be accurately controlled with multi-axial servo-hydraulic controllers, making both static and dynamic loading possible. Sub-structural testing is typically conducted in advanced strong floor and strong wall facilities. An advanced type of sub-structural or component testing is called Hybrid testing, where a numerical – typically finite element – model of the entire structure, controls the actuator system acting on either a sub-structure or a smaller component from the structure.

Component testing is typically carried out to validate new analysis models or simply to qualify a subset of a new structural design. Thus, component tests are often carried out on smaller isolated parts of a larger structural or sub-structural assembly, where the component in some cases additionally can have an idealized geometry to promote a specific failure mechanism. The load configuration is often simple and varying from single axis loading to dual and for some cases tri-axial loading configurations, but can also be more complex with multi-axial setups. However, component testing is mostly carried out in conventional or planar biaxial testing machines or similar smaller test setups using either a specially designed test rig and/or utilizing a strong floor in the rigging construction. Component tests are carried out with quasi-static as well as dynamic fatigue loading, demanding large capacity testing facilities.

 

Equipment

The Center is outstandingly equipped with a large number (exceeding 50) of structural fatigue rated actuators (mostly from MTS) covering the testing range from 5kN to 5000kN, some of which are also well suited for large and full scale testing. These actuators, and the accompanying multi-axial and multi-station controllers, allow either a large number of simultaneous load axis (up to 40) to be used in one large test or up to 16 separate tests to be conducted simultaneously.

The Center also features numerous (approximately 45) versatile self-contained reaction frames intended both for component and material testing. The reaction frames include a high-capacity 5000 kN load frame, a 7.5m tall fatigue testing frame with a capacity of 2500kN, a 250kN/2250Nm axial-torsion fatigue testing machine, a 4x250kN planar-biaxial fatigue testing machine for bi-axial component testing, integrated with a large climatic test chamber, a high-rate 100 kN testing machine capable of achieving piston speeds of up to 30 m/s as well as a wide range of conventional fatigue testing machines ranging from 3 to 1000 kN all with hydraulic grips and the latest generation of MTS and Instron controllers.

The Center has an outstanding capacity to conduct sub-structural testing and to test a broad range of structural components and specimens quasi-statically and dynamically. It is especially well equipped for fatigue testing of structural components and specimens of essentially any size, including components requiring a fatigue load range of the order of mega-Newton. Furthermore, due to the substantial amount of load frames, which can be utilized for one fatigue series, large fatigue test series can typically be completed within a short time span.  

 

The Center is currently being upgraded with a long range of new equipment including:

 

  • Vertical strong wall and floor in connection with a 30 m extension of Building 119 at Lyngby Campus for, e.g., advanced hybrid testing of lightweight structuralcomponents and sub-structures. 

  • Mobile strong floor towers for flexible test set-ups. 

  • Hydraulic high-capacity hardline system of 1800 L/min delivered by MTS and operated by three 515.180 MTS hydraulic pump stations with a capacity of 600 L/min each.

  • 31 additional structural fatigue rated actuators from MTS with capacities ranging from 25 kN to 5.000 kN, including HSM stations with capacities ranging from 180-960 L/min.

  • Four MTS FlexTest 100 multi-axial and multi-station controller systems with a capacity of up to 40 concurrent load axes, including three MTS FlexDAC data loggers with a total of 192 measuring channels.

  • High-capacity fatigue test system from MTS with extra long piston stroke and a capacity of 2.500 kN with the option of extra-high load frequencies.

  • A 4x250kN planar-biaxial fatigue testing machine for both bi-axial material and component testing, integrated with a large climatic test chamber for temperature and humidity control.

  • Fatigue rated 1000 kN testing machine from MTS based on an existing load frame with hydraulic grips.

  • Fatigue rated 250kN/2250Nm axial-torsion testing machine from MTS based on an existing load frame with hydraulic grips.

  • Advanced dual-500kN axis fatigue rated testing machine from MTS based on an existing load frame with hydraulic grips and rotational load axis capacity for in-situ X-ray monitoring of loaded specimens.


Contact

Christian Berggreen
Associate Professor, Laboratory Manager
DTU Mechanical Engineering
+45 45 25 13 73

Search for equipment

https://casmat.dtu.dk/equipment/substructure-and-component-testing
2 JUNE 2020