scholarly journals Integrated computational framework for the design and fabrication of bending-active structures made from flat sheet material

Structures ◽  
2021 ◽  
Vol 34 ◽  
pp. 979-994
Author(s):  
Francesco Laccone ◽  
Luigi Malomo ◽  
Nico Pietroni ◽  
Paolo Cignoni ◽  
Tim Schork
Keyword(s):  
Sheet Material ◽  
Computational Framework ◽  
Active Structures ◽  
Flat Sheet

Application of UF/NF for the treatment of CIP (cleaning in place) rinsing waters: case study in a liquid detergent production plant

2003 ◽  
Vol 3 (5-6) ◽  
pp. 283-288
Author(s):  
M. Forstmeier ◽  
T. Schipolowski ◽  
B. Goers ◽  
G. Wozny
Keyword(s):  
Nonlinear Programming ◽  
Sheet Material ◽  
Mixed Integer ◽  
Production Plant ◽  
Plant Structure ◽  
Water Network ◽  
Liquid Detergent ◽  
Flat Sheet ◽  
Integer Nonlinear Programming

In this paper the applicability of ultrafiltration and nanofiltration for the treatment of rinsing water in a liquid detergent plant has been investigated. Suitable membranes have been found in a membrane screening with flat sheet material, pilot experiments with industrial spiral wound modules under realistic conditions have shown the membranes' potential for reducing the COD load in the wastewater by up to 96%. Finally an optimum membrane plant structure has been derived by mixed integer nonlinear programming optimisation based on the experimental results. The membrane plant has been integrated into a model of the water network according to the concept for retrofit optimization of water networks strategy.

Lofting and Fabrication of Compound-Curved Plates

1993 ◽  
Vol 37 (02) ◽  
pp. 166-175
Author(s):  
John S. Letcher
Keyword(s):  
Plastic Strain ◽  
Numerical Solution ◽  
Gaussian Curvature ◽  
Strain Distribution ◽  
Sheet Material ◽  
Quantitative Description ◽  
Geometric Theory ◽  
Flat Sheet ◽  
Plane Plastic ◽  
The Relationship

The fabrication of plates with compound curvature (nonzero Gaussian curvature) from initially flat sheet material necessarily involves some degree of in-plane plastic strain. A basically geometric theory is presented for modeling and controlling this process, leading to a quantitative description of both the strain distribution required to achieve the compounding, and the relationship between points and curves on the curved surface and the flat material. The theory thus provides accurate methods for lofting (expansion or plane development) of curved plates, as well as quantitative control of the compounding process. Several methods of numerical solution are presented, with illustrative examples.

On the Plastic Tensile Instability Criteria

1969 ◽  
Vol 91 (3) ◽  
pp. 659-663 ◽  
Author(s):  
F. Negroni ◽  
E. G. Thomsen
Keyword(s):  
Strain Hardening ◽  
Sheet Material ◽  
Maximum Load ◽  
Experimental Results ◽  
Strain Rates ◽  
Prior Deformation ◽  
Biaxial Stretching ◽  
Flat Sheet ◽  
Tensile Instability ◽  
Hardening Parameter

The Dorn maximum load criterion and the Swift criterion for plastic tensile instability of a flat sheet stretched by in-plane forces are discussed. Both hypotheses are applicable when an initial nonuniformity of a sheet material is considered but that one is valid which is satisfied first. Experimental results in biaxial stretching of aluminum sheet specimens showed general agreement with both criteria; however, the Dorn maximum load criterion more accurately described the condition for necking when both principal strain rates on the plane of the sheet were positive. The significance and the calculation of the strain hardening parameter n = (ε/σ)(dσ/dε) are discussed, and the effect of prior deformation of the material on instability is analyzed.

scholarly journals Computational design of 3D-printed active lattice structures for reversible shape morphing

2021 ◽  
Author(s):  
Thomas S. Lumpe ◽  
Kristina Shea
Keyword(s):  
Large Scale ◽  
Computational Design ◽  
Lattice Structures ◽  
Functional Requirements ◽  
Initial State ◽  
Computational Framework ◽  
Shape Morphing ◽  
Active Structures ◽  
3D Printed ◽  
Complex Target

Abstract Active structures can adapt to varying environmental conditions and functional requirements by changing their shapes and properties, which makes them suitable for applications in changing environments as found in aerospace and automotive. Of special interest are light and stiff structures with shape morphing capabilities, which is naturally contradictory. Existing concepts in literature can be limited to a single, non-reversible actuation and are difficult to design due to the inherent complexity of large-scale lattices with many elements and complex target deformations. Here, we show how 3D-printed active materials can be combined with an efficient computational framework to design large-scale lattice structures that can change their shape between an initial state and a target state. The reversible deformation is controlled by a single actuation input and heating of the structure. Numerical and experimental results show the generality of the proposed method and the applicability to different problems such as morphing airfoils. Graphic Abstract

Analysing Mechanical Systems in Domestic and Foreign CAD Systems

2018 ◽  
pp. 10-17
Author(s):  
V. A. Martynyuk ◽  
V. A. Trudonoshin ◽  
V. G. Fedoruk
Keyword(s):  
Sheet Material ◽  
The Finite Element Method ◽  
Cad Systems ◽  
Cad System ◽  
Software Products ◽  
Foreign Products ◽  
Nonlinear Algebraic Systems ◽  
Software Product ◽  
Pipeline Design ◽  
The Mathematical Model

The article considers applications of foreign CAD-systems in creating the challenging projects at domestic enterprises and design bureaus. As stated in the article "... presently, there is no domestic CAD-system that could completely replace such foreign products as NX, CATIA, Credo". Besides, due to international cooperation in creating the challenging projects (for example, the project to create a modern wide-body aircraft, proposed jointly with China), it makes sense to use the worldwide known and popular CAD systems (the aforementioned NX, CATIA, Credo). Therefore, in the foreseeable future, we will still have to use foreign software products. Of course, there always remains a question of the reliability of the results obtained. Actually, this question is always open regardless of what software product is used - domestic or foreign. This question has been haunting both developers and users of CAD systems for the last 30 to 40 years. But with using domestic systems, it is much easier to identify the cause of inaccurate results and correct the mathematical models used, the methods of numerical integration applied, and the solution of systems of nonlinear algebraic systems. Everything is much more complicated if we use a foreign software product. All advertising conversations that there is a tool to make the detected errors available to the developers, remain only conversations in the real world. It is easily understandable to domestic users, and, especially, to domestic developers of similar software products. The existing development rates and competition for potential buyers dictate a rigid framework of deadlines for releasing all new versions of the product and introducing the latest developments into commercial product, etc. As a result, the known errors migrate from version to version, and many users have accepted it long ago. Especially, this concerns the less popular tools rather than the most popular applications (modules) of a CAD system. For example, in CAD systems, the "Modeling" module where geometric models of designed parts and assembly units are created has been repeatedly crosschecked. But most of the errors are hidden in applications related to the design of parts from sheet material and to the pipeline design, as well as in applications related to the analysis of moving mechanisms and to the strength or gas dynamic analysis by the finite element method.The article gives a concrete example of a moving mechanism in the analysis of which an error was detected using the mathematical model of external influence (a source of speed) in the NX 10.0 system of Siemens.

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