108 research outputs found
The proper use of artefacts: A philosophical theory of the social constitution of artefact functions
No full textArtefacts are humanly designed objects with a function. Their proper function is what they are for. This book develops a theory of these functions on the basis of the idea that artefacts are used in a social context. Current theories of artefact functions are inadequate to deal with this special character. Functions of artefacts are defined partly in the traditional way, referring to their physical nature and causal history, but an additional constitutive feature is introduced and analysed in detail: the social context in the form of the institutionalisation of use. Func-tions can be partly defined in terms of institutionalised use. This analysis provides the basis for the understanding of artefact use and the evaluation of artefact use. Then further consequences for understanding artefacts and their functions are investi-gated and developed. In the first place it is shown how this view of functions helps understand a little investigated aspect of the communication of artefact functions, namely by way of the artefacts structural aspects. The artefact is, as it were, the carrier of symbolic meaning con-cerning its own proper function. For this analysis the pragmatic approach to language and linguistic communication is applied and extended to cover the case of function communica-tion. In the second place, the normative notion of proper function is used to give an action theoretic account of artefact use, enabling us to understand and evaluate it. The plan account of intentional action is invoked, which enables the proper use of artefacts to be analysed in terms of a use plan of the artefact. This shows how the social features of the proper function are actual part of an agents reasons for using an artefact in a particular way. Thus, the more standard accounts of action in terms of rationality and rational reconstructions can be com-bined with the social features constituting artefact functions. The analysis of artefact functions thus provides the material for a thorough analysis of artefact use.Technology, Policy and Managemen
Lumped impulses, discrete displacements and a moving load analysis
No full textFinite element models are usually presented as relations between lumped forces and discrete displacements. Mostly finite element models are found by the elaboration of the method of the virtual work - which is a special case of the Galerkin's variational principle -. By application of Galerkin's variational principle to time dependent problems, considering elements bordered by ge()metry and time b()undaries, we obtain relations between lumped impulses and discrete displacements. The analogy with respect to static models which formulates relati()ns between lumped forces and discrete displacements is striking. Models are formulated using linear and quadratic displacement fields with respect to time. Free model parameters are used to manipulate numerical stability, accuracy and numerical damping. These numerical tools are used for the numerical simulation ()f a m()ving vehicle at a rail track structure. The analysis sh()ws the natural way ()f m()delling a moving structure (the train) with respect to a fixed supporting structure (the rail track).Civil Engineering and Geoscience
Toepassing van de elementenmethode op problemen uit de continua welke axiaalsymmetrisch zijn te formuleren
No full textDesign & ConstructionCivil Engineering and Geoscience
Artificial Orthotropy
No full textAn homogeneous orthotropic plate model is presented for the idealisation of composed plate structures with orthotropy properties. The model requires the specification of 14 material parameters and couples membrane and bending forces. To find these parameters a finite element procedure is proposed that calculates these parameters with the help of a plane strain analysis and a simple potential analysis for a series of basic load cases. These parameters are substituted into the orthotropy model for the analysis of the homogeneous orthotropic plate. Both analysis steps can be performed with simple 2D finite element programs such as KOLA. Two examples show the performance of these modelsCivil Engineering and Geoscience
The numerical calculation of shear properties of members
No full textCivil Engineering and Geoscience
Lumped Pulses and Discrete Displacements: A Physical Way to Understand Numerical Dynamics
No full textCivil Engineering and Geoscience
Finite element models for the steady state analysis of moving loads
No full textThe analysis of structures subjected to fast moving loads is a subject of growing interest in railway and pavement engineering. The applications of transient analyses using finite element models, however, are still very limited. The faster a load moves the more elements we need to model the structure. Even at fast workstations and main frame computers a moderate accurate analysis requires a huge amount of computer time. Many problems can be solved more efficient by application of a steady state analysis using a moving reference system. Based upon this formulation we will develop finite element models that travel together with the moving loads. Such an analysis can be performed with the computer power and execution time necessary for the solution of a common static problem, thus at a normal PC. Especially in the design phase such an analysis is very attractive.Railway EngineeringCivil Engineering and Geoscience
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