3,345 research outputs found
Rosetta lander Philae - soil strength analysis
No full textThe landing of Philae, the lander of ESA’s ROSETTA-mission, on November 12th 2014 on Comet 67P/Churyumov-Gerasimenko, was planned as a descent with passive landing activating a damper system and anchoring by harpoons at touch-down. The lander was not fixed to the ground at touch-down due to failing harpoons. The lander damper, however, was actuated for a length of 42.6 mm with a maximal speed of 0.08 m/s, while the lander speed was 1 m/s. Based on the damper data and a detailed mechanical model of Philae, an estimate can be made for the forces acting and the energy dissipated at touch-down inside the lander and the energy dissipated by ground penetration. The forces acting at ground penetration provide constraints on the mechanical strength of the soil. Two different soil models are investigated. Assuming constant compressive strength σ, one obtains σ ≈ 2 kPa. Assuming an increasing σs strength with penetration depth with results in σs = 3kPa/m fits the damper data best
Reptricket. Förord till Lars Gustafsson: Mot noll
No full textIntroduction to a collection of philosophical essays by Swedish author Lars Gustafsson (b. 1936)
3D roll-forming of hat-profile with variable depth and width
No full textThe use of roll-formed products in automotive, furniture, buildings etc. increases every year due to the low part-production cost and the complicated cross-sections that can be produced. The limitation with roll-forming until recent years is that one could only produce profiles with a constant cross-section in the longitudinal direction. About eight years ago ORTIC AB [1] developed a machine in which it was possible to produce profiles with a variable width (“3D roll-forming”) for the building industry. Experimental equipment was recently built for research and prototyping of profiles with variable cross-section in both width and depth for the automotive industry. The objective with the current study is to investigate the new tooling concept that makes it possible to roll-form hat-profiles, made of ultra high strength steel, with variable cross-section in depth and width. The result shows that it is possible to produce 3D roll-formed profiles with close tolerances
3D roll-forming of hat-profile with variable depth and width [Elektronisk resurs]
No full textThe use of roll-formed products in automotive, furniture, buildings etc. increases every year due to the low part-production cost and the complicated cross-sections that can be produced. The limitation with roll-forming until recent years is that one could only produce profiles with a constant cross-section in the longitudinal direction. About eight years ago ORTIC AB [1] developed a machine in which it was possible to produce profiles with a variable width (“3D roll-forming”) for the building industry. Experimental equipment was recently built for research and prototyping of profiles with variable cross-section in both width and depth for the automotive industry. The objective with the current study is to investigate the new tooling concept that makes it possible to roll-form hat-profiles, made of ultra high strength steel, with variable cross-section in depth and width. The result shows that it is possible to produce 3D roll-formed profiles with close tolerances.</p
Skrovlig eller slät yta - spelar det någon roll?
No full textHur ofta ser du över skrovet på din båt? Hur viktig är ytans skick? Spelar det någon roll när du ”bara” cruisingseglar? Spelar det någon roll när du kappseglar? Hur stora är fartförlusterna? Finns det en ”tillåten” skrovlighet? Frågorna är många. Lars Larsson, Professor i Hydrodynamik vid Chalmers, har svaren. Det här är första artikeln i en serie om teorierna bakom design, konstruktion och andra mer eller mindre förklarliga fenomen inom seglingsområdet
Author Functions in Lars Kepler\u27s The Hypnotist: An Analysis
No full textThis paper examines Foucault\u27s notion of the author function as it pertains to Lars Kepler\u27s bestselling 2011 crime thriller, The Hypnotist. Lars Kepler is the pseudonym of a Swedish husband-wife writing duo, making him the perfect subject for analysis centering on illusory notion of the author. This paper will answer these questions: Who is the true author of The Hypnotist? What factors influence the author function of this bestelling novel? And what can The Hypnotist phenomenon tell us about the relationships between authors and their readers? This paper will demonstrate that no literary works may be ascribed to an individual person, and that authors hold no privileged knowledge of the works they produce, because authors cease to be authors the moment pen is lifted from page
Skrovlig eller slät yta - spelar det någon roll?
No full textHur ofta ser du över skrovet på din båt? Hur viktig är ytans skick? Spelar det någon roll när du ”bara” cruisingseglar? Spelar det någon roll när du kappseglar? Hur stora är fartförlusterna? Finns det en ”tillåten” skrovlighet? Frågorna är många. Lars Larsson, Professor i Hydrodynamik vid Chalmers, har svaren. Det här är första artikeln i en serie om teorierna bakom design, konstruktion och andra mer eller mindre förklarliga fenomen inom seglingsområdet
The Swedish Fiscal Policy Council
No full textN/AThe Swedish Fiscal Policy Council; fiscal policy; government policy
Skrovlig eller sl\ue4t yta - spelar det n\ue5gon roll?
No full textHur ofta ser du \uf6ver skrovet p\ue5 din b\ue5t? Hur viktig \ue4r ytans skick? Spelar det n\ue5gon roll n\ue4r du ”bara” cruisingseglar? Spelar det n\ue5gon roll n\ue4r du kappseglar? Hur stora \ue4r fartf\uf6rlusterna? Finns det en ”till\ue5ten” skrovlighet? Fr\ue5gorna \ue4r m\ue5nga. Lars Larsson, Professor i Hydrodynamik vid Chalmers, har svaren. Det h\ue4r \ue4r f\uf6rsta artikeln i en serie om teorierna bakom design, konstruktion och andra mer eller mindre f\uf6rklarliga fenomen inom seglingsomr\ue5det
Investigation into forming sequences for the incremental forming of doubly curved plates using the line array roll set (LARS) process
No full textThe line array roll set (LARS) process [7] proposed by the authors is an effective metal forming process used to manufacture doubly curved metal plates. To obtain a final shape with the desired bend radii and to minimize any possible defects, the process for forming the desired shape should be systematically and accurately designed. The major purpose of the present work is to analyze the effect of the forming sequences in the LARS process. The experiments are conducted using three types of forming sequences, and the final bend radii and the quality of the formed plates produced by the LARS process are evaluated. It is found that it is more effective to form a doubly curved plate through a singly curved shape in order to improve the quality of the formed plate. A series of forming experiments with various bending radii are conducted and the interaction phenomena in double curvature bending are observed. (C) 2009 Elsevier Ltd. All rights reserved
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