Stiffened CFRP-Panels Under Buckling Loads: Modeling, Analysis, Optimization

Author(s):  
Hans A. Eschenauer ◽  
Christof M. Weber

Abstract The present paper addresses the optimal layout of stiffened fiber composite plates (Fig. 1) considering buckling constraints; these plates are increasingly applied in many fields of engineering (air- and spacecraft technology, automotive industries, boatbuilding etc.). This particular area of structural optimization still requires substantial investigations into its fundamentals. The structural analysis alone for the treatment of this type of problems may increase to such a degree that the complete optimization process requires extremely long computation times due to the processing of a high amount of data, a fact that calls for the development of “intelligent” procedures in order to reduce the computation effort to a tolerable measure and to maintain reduplicability of the whole process. For this purpose, a so-called “constructive design model” is introduced.

2019 ◽  
Author(s):  
Sergey Selyugin

In the present paper the flat composite plates in buckling are studied. The plates have a symmetric lay-up and loaded along their piecewise-smooth contour by the in-plane forces. The consideration employs the Classical Lamination Plate Theory. A reciprocity theorem for the buckling states of the plate is derived and analyzed. The theorem may be used as a benchmark for the structural analysis and the optimization software.


Author(s):  
Karina M. Tsuruta ◽  
Leandro R. Cunha ◽  
Raquel S. L. Rade ◽  
Domingos A. Rade

The aim of this paper is to evaluate the use of the Structural Health Monitoring (SHM) technique based on the concept of electromechanical impedance for the assessment of low-energy impact damage in laminated carbon-fiber composite plates. The experiments were carried-out by using an especially designed pendulum, and were planned in such a way to accommodate a range of test conditions, such as impact energy and dimension of the impacting piece. Also, it was investigated the influence of the frequency band in which the impedance functions are measured. Additionally, statistical metamodels were built aiming at establishing functional relations between the values of the damage metric and impact energy for single and multiple impacts. The obtained results demonstrate the capability of the monitoring method to identify various damage levels corresponding to different impact conditions.


1999 ◽  
Vol 16 (7) ◽  
pp. 518-519 ◽  
Author(s):  
Jian-chun Cheng ◽  
Jun-bo Han ◽  
Shu-yi Zhang ◽  
Yves Berthelot

2007 ◽  
Vol 348-349 ◽  
pp. 725-728 ◽  
Author(s):  
Omer Soykasap ◽  
Şükrü Karakaya

In this study, the structural optimization of laminated composite plates for maximum buckling load capacity is performed by using genetic algorithm. The composite plate under consideration is a 64-ply laminate made of graphite/epoxy, is simply supported on four sides, and subject to in-plane compressive static loads. The critical buckling loads are determined for several load cases and different plate aspect ratios using 2-ply stacks of 02, ±45, 902. The problem has multiple global solutions, the results of which are compared with previously published results.


Author(s):  
Christiane Lopes Machado ◽  
Marco Antonio Santos

PROJEMAR S. A., a naval and offshore design company at Brasil has developed several conversion projects of FPSO’s to operate at Campos Basin. This way, PROJEMAR faced some interface difficulty in the structural design of the topside supports, mainly for the vessel reinforcement. The structural analysis of the cargo region, when performed together with the topside supports and loads, introduces significant buckling and fatigue problems in the main transverse and longitudinal structure of the vessel. The solution adopted in first instance is to reinforce the transverse structure and longitudinal bulkheads of the cargo tanks just below the topside supports. This reinforcement is expensive and takes a lot of time to be done, as hundreds of buckling bars should be installed. In order to avoid this work inside the cargo region, PROJEMAR evaluated this study to minimize the steelwork inside the cargo region, and to optimize the steel weight for topside supports. PROJEMAR analyzed three different concepts of topside supports: two transverse bulkheads supporting each topside module, two sets of strong brackets supporting each topside module, and sets of pillars supporting each topside modules. The results present the amount of steelwork inside and outside the cargo tanks, the total amount of steel reinforcement after the evaluation of stress, deflection, buckling and fatigue verification. The conclusions present cost and benefit for each solution, and some discussions on the time acceleration for the conversion.


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