Injection 3D concrete printing in a carrier liquid - Underlying physics and applications to lightweight space frame structures

The article presents experimental study results of the deformation state of composite cable space frame structures, including composite steel-concrete structures. Composite cable space frame structures are three-dimensional roof framing of long-span buildings. The designed constructions are a new type of roof framing structures and consist of typical composite steel-concrete modules connected with steel cable elements. The operation of composite cable space frame structures under load is characterised by geometric nonlinearity. The aim of the research is to study the deformation state and changing the geometric shape of experimental structures under the influence of external load. The technique of studying the deformation state of the composite cable space frame structures is based on the principles of digital photogrammetry. At the limit state the composite cable space frame structures change their regular shape. In this case, the central vertical points get the greatest vertical displacements, and the displacement value decreases closer to the supports. It is defined that the investigated construction has demonstrated combined action of all its components during the test, which indicates its effectiveness. The application of the photogrammetry method made possible to determine the moment of reaching the limit state of the composite cable space frame structures concretely.

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Joining automotive space frame structures by filament winding

CIRP Journal of Manufacturing Science and Technology ◽

10.1016/j.cirpj.2013.02.003 ◽

2013 ◽

Vol 6 (2) ◽

pp. 98-101 ◽

Cited By ~ 12

Author(s):

J. Fleischer ◽

J. Schaedel

Keyword(s):

Filament Winding ◽

Frame Structures ◽

Space Frame

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Nonlinear Dynamic Analysis of Space Frame Structures by Discrete Element Method

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.638-640.1716 ◽

2014 ◽

Vol 638-640 ◽

pp. 1716-1719 ◽

Cited By ~ 3

Author(s):

Nian Qi ◽

Ji Hong Ye

Keyword(s):

Discrete Element Method ◽

Dynamic Analysis ◽

Nonlinear Dynamic ◽

Nonlinear Dynamic Analysis ◽

Discrete Element ◽

Internal Force ◽

Frame Structures ◽

Space Frame ◽

Bond Model ◽

Element Method

This document explores the possibility of the discrete element method (DEM) being applied in nonlinear dynamic analysis of space frame structures. The method models the analyzed object to be composed by finite particles and the Newton’s second law is applied to describe each particle’s motion. The parallel-bond model is adopted during the calculation of internal force and moment arising from the deformation. The procedure of analysis is vastly simple, accurate and versatile. Numerical examples are given to demonstrate the accuracy and applicability of this method in handling the large deflection and dynamic behaviour of space frame structures. Besides, the method does not need to form stiffness matrix or iterations, so it is more advantageous than traditional nonlinear finite element method.

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Accuracy Improvement of a Machine Kinematics for the Product Flexible Machining of Curved Extrusion Profiles

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.43.135 ◽

2008 ◽

Vol 43 ◽

pp. 135-144

Author(s):

Jürgen Fleischer ◽

Jan Philipp Schmidt-Ewig

Keyword(s):

Traffic Engineering ◽

Complex Geometry ◽

Frame Structures ◽

Work Piece ◽

Machining Accuracy ◽

Process Chain ◽

Space Frame ◽

Frame Design ◽

Machining Center ◽

Technical Effort

Within traffic engineering, the importance of lightweight space frame structures continuously grows. The space frame design offers many advantages for light weight construction but also brings challenges for the production technology. For example, the important requests concerning product flexibility and reconfiguration can only be achieved with a high technical effort, if current machine technology is used. For this reason, the collaborative research center SFB/TR10 investigates the scientific fundamentals of a process chain for the product flexible and automated production of space frame structures. An important component in space frame structures are curved extrusion profiles. Within the investigated process chain, the extrusions must be machined mechanically in order to apply holes and to prepare the extrusion ends for the following welding operation.The machining is currently done by clamping the profile into a fixture and processing it within a machining center. This procedure has two disadvantages due to the complex geometry and the partially high length of the extrusion profiles: On the one hand, a complex fixture is needed for clamping the work piece [1]. On the other hand, a machining center with a large workspace and five machine axes is required [2]. Due to this, the product flexible machining with current technology is only possible with high technical and economical effort. For this reason, a new machine concept for the product flexible machining of three dimensionally curved extrusion profiles was developed at the University of Karlsruhe. In this paper, the function of the machine is explained and a prototype is presented. In addition, investigation results of the machining accuracy are shown and possibilities for improving the precision are discussed.

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