Towards a coupled structural and economical design procedure of unstiffened isotropic shell structures

2019 ◽  
Vol 145 ◽  
pp. 106416 ◽  
Author(s):  
Pawel Lyssakow ◽  
Max Krause ◽  
Linus Friedrich ◽  
Kai-Uwe Schröder
2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
H. A. Khawaja ◽  
T. A. Bertelsen ◽  
R. Andreassen ◽  
M. Moatamedi

The paper gives the study of the response of carbon fiber reinforced polymers (CRFP) quasi-isotropic shell structures under the influence of dynamic loading. The quasi-isotropic CRFP shell specimens are fabricated using Multipreg E720 laminates. These laminates are laid in such a way that shell structure has equal strength and mechanical properties in the two-dimensional (2D) plane and hence can be regarded as quasi-isotropic. In this study, the dynamic loading is generated using shock waves in a shock tube experimental setup. The strain and pressure data is collected from the experiments. Additional tests are carried out using Material Test System (MTS) for both tensile and flexural response of CRFP. Results obtained from experiments are compared with numerical simulations using ANSYS Multiphysics 14.0 finite element method (FEM) package. The numerical simulation and experimental results are found to be in good agreement.


1993 ◽  
Vol 8 (4) ◽  
pp. 251-259
Author(s):  
N.A. Gogoleva

This paper discusses the conceptual design of decorative crystalline domed structures. The application of the structure itself as a decorative element in combination with three ways of shape-forming: spatial, structural and geometrical, is a feature of such composite shape formation of crystalline domed shells. The author developed a computer-aided design procedure for decorative means of forming crystalline dome-and-shell structures. The procedure can be applied to preliminary multiple-alternative geometrical modelling of ornamental-decorative constructural forming of networks as well as designing the decorative finish to domed shell surfaces.


2009 ◽  
Vol 46 (3) ◽  
pp. 296-305 ◽  
Author(s):  
Luo Yang ◽  
Robert Liang

A comprehensive database is developed for the setup for piles driven into sand. Based on the compiled pile-testing data, pile setup is significant and continues to develop for a long time after pile installation. The statistical analysis shows that a logarithm-normal distribution can be used to describe the probabilistic characteristics of the predicted setup capacity using the Skov and Denver equation. The main objective of this paper is to incorporate the setup effect into a reliability-based load and resistance factor design (LRFD) of driven piles in sand. The first-order reliability method (FORM) is used to derive separate resistance factors that would account for different degrees of uncertainties associated with measured short-term capacity and predicted setup capacity. The incorporation of setup effects in the LRFD helps improve the prediction of total capacity of driven piles, resulting in more economical design. A practical design procedure within the LRFD framework to incorporate the pile setup effects is outlined.


Author(s):  
Naoki Yoshimura ◽  
Shunji Kataoka ◽  
Takuya Sato

A fixed tubesheet type heat exchanger with semi-ellipsoidal heads which is dealt with in this paper has been adopted for refrigerant heat exchange process in LNG Plant. Since the conventional design standards, e.g. ASME Sec VIII Div.1 and TEMA, are not meant to be used for such a special type of heat exchanger, FEA should be performed to determine minimum required thickness of the tubesheet. The elastic design procedure uses a stress classification methodology to guard against failure due to gross plastic deformation. According to the design standards, mechanical stresses in the tubesheet due to tube-side and/or shell-side pressure are defined as the primary membrane and bending stress and are evaluated by comparing with allowable values of the primary stress. For the special type of heat exchanger, however, stresses in the tubesheet obtained by FEA are actually complex combination of primary and secondary stresses. Application of this conventional design approach to the FEA-calculated stresses in tubesheet may lead to over-conservative design. In helping to establish reliable and economical design of the tubesheet for such a special type of heat exchanger, authors conducted FEA investigation employing axisymmetric analysis model. Considering the geometric parameters, such as thickness of a tubesheet, heads type and shell dimension, the characteristics of tubesheet stresses was investigated and an appropriate stress classification was proposed.


2010 ◽  
Vol 133 (1) ◽  
Author(s):  
J. Michael Rotter

This paper outlines key aspects of the new European Standard on the Strength and Stability of Metal Shells EN 1993-1-6 with its extended commentary and expansion in the fifth edition of the European Recommendations on Shell Buckling. This European design standard is the first to be strongly oriented toward numerical analyses in design, with clear distinctions between different classes of both analysis and fabrication. It presents a different style of standard: Each limit state is defined in a separate chapter, but all shell geometries are treated and all analysis types are used within each chapter. The strength evaluation criteria differ according to the calculation that has been made. This new structure, with its new paradigm that permits generalization of the design procedure for all thin shells, geometries, load cases, boundary conditions, and qualities, represents a major step forward. It also offers the opportunity for future research studies of shell structures to be undertaken within a coherent conceptual framework that is completely general. The EN 1993-1-6 standard goes a long way toward bridging the gap between the computational engineering mechanics and structural engineering design communities. Unfortunately, this European standard EN 1993-1-6 has a complex and extensive background that cannot be stated within the document so the European Recommendations on Shell Stability, now published in its fifth edition, gives an extensive commentary, many expanded rules, and many additional geometries and load cases that are not formally presented within the standard itself. The development of both EN 1993-1-6 and the recommendations has been the work of the Eurocode shell structures development committee CEN/TC250/SC3/PT4 and the European Convention for Constructional Steelwork committee (ECCS) TWG 8.4. It is presented here by the convener of these two committees. This paper explains the reasoning behind several particular choices that have been taken in developing the standard, occasionally running counter to traditional views. It also identifies several tricky issues that have not been addressed well in the shell buckling literature but that have arisen through the attempts to achieve completely general rules and which need imaginative answers to ensure a fully consistent treatment of all systems. It is hoped that this paper will assist researchers and designers to understand the rules and recommendations and will encourage researchers to undertake and present their work in a manner that permits its rapid adoption into the new standardized design procedures.


PCI Journal ◽  
1993 ◽  
Vol 38 (5) ◽  
pp. 20-29 ◽  
Author(s):  
Mary Lou Ralls ◽  
Luis Ybanez ◽  
John J. Panak

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