Development of a laser projection system for the ELT

TNO, in close cooperation with Demcon, has designed the Laser Projection Subsystem (LPS) for ESO’s Extremely Large Telescope (ELT). The ELT LPS will consist of up to 8 laser projection subunits. The design is based on the Four Laser Guide Star Facility (4LGSF), built for the ESO Very Large Telescope (VLT) (5). The VLT AO system has been...

SMATT, a tool that measures the mechanical loads on the support points of the TMT primary mirror supports

TMT will be a telescope with 492 segments making up the primary mirror. Each of these segments is supported with a highly sophisticated Segment Support Assembly (SSA) and each of them is to be tested for acceptance using a tool called SMATT. This tool will be mounted on top of each SSA and provides the load distribution applied to its 27 support...

Lateral torsional buckling of an I-shaped hoisting spreader beam

Towards sustainability through energy efficient buildings' design: semantic labels

When designing buildings, it is a challenge to take into account Energy Efficiency in the early design stage. This is especially difficult for hospital designs, because these buildings comprise many different room types and functions. This greatly increases the number of design directions available. Choices made early on in the design process...

Designing the primary mirror support for the E-ELT

Described is the M1 segment support, as designed by TNO in the period 2015- 2016. The design has significantly changed and improved compared to the earlier designs. During the period 2009-2010 prototypes for the primary mirror support of the E-ELT have been developed. These have been extensively tested by ESO. Design improvement were found to be...

New regulations for hollow core slabs after premature partial collapse

In October 2007, a floor made up of pre-cast prestressed hollow core floor elements suffered early partial collapse during a fire in a carpark of a moderately high new building in Rotterdam, predominantly in use for housing and for limited enterprise. The damage pattern revealed horizontal cracks through the webs of the hollow core slabs,...

Design rules for lateral torsional buckling of channel sections subject to web loading

Channel sections are widely used in practice as beams. However, design rules for eccentrically loaded (not through shear centre) beams with channel cross-sections are not available in Eurocode 3. In this paper five proposed design rules are summarised, explained and their validity is checked by Finite Element analyses. The design rules yield...

A semantic feature model for conceptual design of warships

In the conceptual design phase of warships, important decisions are made based on relatively little information. It isdecided here whether a concept is feasible, and whether the resulting model should be the basis for further development. The conceptual design phase is characterised by the frequent use of rule of the thumb methods. These methods...

Statically determined structures: Tension between classical and modern design

The two most important characteristics of opto-mechanical structures used in space or for astronomy are high accuracy and stability. Much time, money and energy is invested in achieving this. However, because resources are limited, it is important to realize that the cost of an instrument is mainly determined during the design process. Three...

Development of design rules for adhesive bonded joints

This article deals with the development of design rules for structural adhesive bonded joints. In daily practice engineers are confronted with the problem to verify the reliability of their designs. This can be done with use of an experimental programme, but for the marine, transport, building and civil engineering sectors this will not be an...

Design rules for matrix signs: The maximum allowable deviation from grid position

The just noticeable deviation (jnd) of the position of light points in the grid structure of matrix signs was determined in a laboratory experiment. The stimuli, consisting of either lines (10 light points) or areas (10´10 light points), were presented on a colour VDU-screen. The variables tested were light point distance (2.75, 1.38 or 0.688...