Strain field in doubly curved surface

This paper presents algorithm for development of structural and continuous curved surface into a planar and non planar (radial) shape in 3D space. The development process is modeled by application of strain in certain plane from the curved surface to its planar development. A doubly curved surface has been generated for the purpose of technical studies. Important features of the approach include formulations of the coefficients of first fundamental form, second fundamental form, Gaussian curvature and Serret Frenet curve. The approximate strain field is obtained by solving a constrained linear and nonlinear problem in algorithm

Using Approximate Method for the Construction of Mosque Domes

Domes remain a unique structure in building construction as a result of stylistic forms and composition in the field of architecture. They are important elements that adequately define the Islamic architecture. The construction of domes which is a doubly curved surface and formed by rectilinear structures always resulted in difficulties to get the curvilinear shape correctly. The study therefore made the use of an approximate method to develop the dome using materials that are provided in the locality. The knowledge of descriptive geometry in surface development was adopted to obtain approximation cone components that produce the hemispherical dome. The components were properly installed and supported by centering which composed eight equally spaced timber frameworks that were supported by planks. Lack of appropriate modern technological advancement should not be factor militating against production of perfect forms, thus appropriate technical drawing basic skills should be acquired by the builders to take the construction of dome from a poor to a good system of accurate centering with good quality control

Modelling curved-layered printing paths for fabricating large-scale construction components

In this paper, a non-conventional way of additive manufacturing, curved-layered printing, has been applied to large-scale construction process. Despite the number of research works on Curved Layered Fused Deposition Modelling (CLFDM) over the last decade, few practical applications have been reported. An alternative method adopting the CLFDM principle, that generates a curved-layered printing path, was developed using a single scripting environment called Grasshopper – a plugin of Rhinoceros® . The method was evaluated with the 3D Concrete Printing process developed at Loughborough University. The evaluation of the method including the results of simulation and printing revealed three principal benefits compared with existing flat-layered printing paths, which are particularly beneficial to large-scale AM techniques: (i) better surface quality, (ii) shorter printing time and (iii) higher surface strengths

Möbius Geometry and Cyclidic Nets: A Framework for Complex Shape Generation

International audienceFree-form architecture challenges architects, engineers and builders. The geometrical rationalization of complex structures requires sophisticated tools. To this day, two frameworks are commonly used: NURBS modeling and mesh-based approaches. The authors propose an alternative modeling framework called generalized cyclidic nets that automatically yields optimal geometrical properties for the façade and the structure. This framework uses a base circular mesh and Dupin cyclides, which are natural objects of the geometry of circles in space, also known as Möbius geometry. This paper illustrates how new shapes can be generated from generalized cyclidic nets. Finally, it is demonstrated that this framework gives a simple method to generate curved-creases on free-forms. These findings open new perspectives for structural design of complex shells

Isogonal moulding surfaces: A family of shapes for high node congruence in free-form structures

International audienceThe design of free-form structures is governed by structural and geometric considerations, the latter ones being closely linked to the costs of fabrication. If some construction constraints have been studied extensively, the question of the repeatability of nodes in free-form structures has rarely been addressed yet. In this paper, a family of surfaces that can be optimized regarding typical geometrical constraints and that exhibit high node congruence is proposed. They correspond to particular meshes of moulding surfaces and are called isogonal moulding surfaces by the authors. The geometrical properties of these surfaces are discussed. In particular, it is shown how to derive Edge Offset Mesh from them. It is also demonstrated that they represent all the possible meshes parallel to surfaces of revolution. Finally, the reader is introduced to some computational strategies linked to isogonal moulding surfaces

Design and manufacturing concepts for thermoplastic structures

Results to date on the application of two manufacturing techniques, fiber placement and single diaphragm/coconsolidation, to produce cost-effective, thermoplastic composite (TPC), primary fuselage structure are presented. Applications relative to fuselage upper cover structure indicate potential cost savings relative to conventional approaches. Progress is also presented on efforts concerned with other design details which take advantage of thermoplastic composites such as fastener less stiffener/frame attachments. In addition, results are presented on the development and verification testing of a composite lug analysis program which incorporates through-the-thickness effects