Optimal Winding Conditions of Flat Steel Ribbon Wound Pressure Vessels With Controllable Stresses

2008 ◽  
Vol 75 (4) ◽  
Author(s):  
Chuanxiang Zheng ◽  
Shaohui Lei
Keyword(s):  
Optimal Design ◽  
Stress Analysis ◽  
Design Method ◽  
Pressure Vessels ◽  
Layer By Layer ◽  
Shell Layer ◽  
Discrete Structure ◽  
Flat Steel ◽  
Optimal Design Method ◽  
Steel Ribbon

Stress analysis of flat steel ribbon wound pressure vessels (FSRWPVs) is very difficult because they have a special discrete structure and complex pretensions exit in the flat steel ribbons, which are wound around the inner shell layer by layer. An analytical multilayered model for stress analysis is presented in this paper, which involves the effect of prestress in every flat steel ribbon layer as well as in the inner shell. Based on this model, an optimal design method for FSRWPV is suggested, which can assure a reasonable stress level and distribution along the wall thickness during the operation. A practical example of a large FSRWPV is finally given for illustration.

Comparative Study for the Design of Optimal Composite Pressure Vessels

2010 ◽  
Vol 442 ◽  
pp. 381-388 ◽  
Author(s):  
A.M. Butt ◽  
Syed Waheed-ul-Haq
Keyword(s):  
Optimal Design ◽  
Design Method ◽  
Transversely Isotropic ◽  
Pressure Vessels ◽  
Filament Winding ◽  
Stress Profile ◽  
Element Analysis ◽  
Optimal Design Method ◽  
Internal Volume ◽  
Composite Pressure Vessels

Composite pressure vessels require special design attention to the dome region because of the varying wind angles generated using the filament winding process. Geometric variations in the dome region cause the fiber to change angels and thickness and hence offer difficulty to acquire a constant stress profile (isotensoid). Therefore a dome contour which allows an isotensoid behavior is the required structure. Two design methods to generate dome profiles for similar dome openings were investigated namely Netting Analysis and Optimal Design method. Both methods assume that loads are carried by the fiber alone (monotropic) ignoring the complete composite behavior. Former method produced a lower dome internal volume and a higher fiber thickness as compared to the later optimal design method when studied against different normalized dome opening radiuses. The optimal dome contour was studied in ANSYS with a trial design. The dome was considered to have transversely isotropic property with a dome contour based on monotropic model. While investigating the dome with non linear large displacement finite element analysis, the dome still exhibited isotensoid behavior with transverse isotropic material assignment. Elliptic integrals were used to generate the optimal dome contours and hence elliptic dome contours were formed which were isotensoid in nature with complete composite representation.

scholarly journals Development of Optimal Design Method for Steel Double-Beam Floor System Considering Rotational Constraints

2021 ◽  
Vol 11 (7) ◽  
pp. 3266
Author(s):  
Insub Choi ◽  
Dongwon Kim ◽  
Junhee Kim
Keyword(s):  
Optimal Design ◽  
Design Process ◽  
Design Method ◽  
Steel Beams ◽  
High Gravity ◽  
Double Beam ◽  
Iterative Analysis ◽  
Floor Systems ◽  
Optimal Design Method ◽  
Floor System

Under high gravity loads, steel double-beam floor systems need to be reinforced by beam-end concrete panels to reduce the material quantity since rotational constraints from the concrete panel can decrease the moment demand by inducing a negative moment at the ends of the beams. However, the optimal design process for the material quantity of steel beams requires a time-consuming iterative analysis for the entire floor system while especially keeping in consideration the rotational constraints in composite connections between the concrete panel and steel beams. This study aimed to develop an optimal design method with the LM (Length-Moment) index for the steel double-beam floor system to minimize material quantity without the iterative design process. The LM index is an indicator that can select a minimum cross-section of the steel beams in consideration of the flexural strength by lateral-torsional buckling. To verify the proposed design method, the material quantities between the proposed and code-based design methods were compared at various gravity loads. The proposed design method successfully optimized the material quantity of the steel double-beam floor systems without the iterative analysis by simply choosing the LM index of the steel beams that can minimize objective function while satisfying the safety-related constraint conditions. In particular, under the high gravity loads, the proposed design method was superb at providing a quantity-optimized design option. Thus, the proposed optimal design method can be an alternative for designing the steel double-beam floor system.

scholarly journals D-Optimal Design for Information Driven Identification of Static Nonlinear Elements

2021 ◽  
Author(s):  
Nalika Ulapane ◽  
Karthick Thiyagarajan ◽  
sarath kodagoda ◽  
Linh Nguyen
Keyword(s):  
Optimal Design ◽  
Model Calibration ◽  
Design Method ◽  
Single Input Single Output ◽  
Single Output ◽  
Order Polynomial ◽  
Information Maximization ◽  
Pros And Cons ◽  
Single Input ◽  
Optimal Design Method

<div>Identification of static nonlinear elements (i.e., nonlinear elements whose outputs depend only on the present value of inputs) is crucial for the success of system identification tasks. Identification of static nonlinear elements though can pose several challenges. Two of the main challenges are: (1) mathematical models describing the elements being unknown and thus requiring black-box identification; and (2) collection of sufficiently informative measurements. With the aim of addressing the two challenges, we propose in this paper a method of predetermining informative measurement points offline (i.e., prior to conducting experiments or seeing any measured data), and using those measurements for online model calibration. Since we deal with an unknown model structure scenario, a high order polynomial model is assumed. Over fit and under fit avoidance are achieved via checking model convergence via an iterative means. Model dependent information maximization is done via a D-optimal design of experiments strategy. Due to experiments being designed offline and being designed prior to conducting measurements, this method eases off the computation burden at the point of conducting measurements. The need for in-the-loop information maximization while conducting measurements is avoided. We conclude by comparing the proposed D-optimal design method with a method of in-the-loop information maximization and point out the pros and cons. The method is demonstrated for the single-input-single-output (SISO) static nonlinear element case. The method can be extended to MISO systems as well.</div>

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