Optimal Design of Panel Reinforcements With Ribs Made of Plates

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Shanglong Zhang ◽  
Julián A. Norato
Keyword(s):  
Computer Aided Design ◽  
Pressure Vessels ◽  
Constant Thickness ◽  
Plate Structures ◽  
Aircraft Wings ◽  
Ship Hulls ◽  
Plate Elements ◽  
Reinforcing Ribs ◽  
Aided Design ◽  
And Storage

The stiffness of plate structures can be significantly improved by adding reinforcing ribs. In this paper, we are concerned with the stiffening of panels using ribs made of constant-thickness plates. These ribs are common in, for example, the reinforcement of ship hulls, aircraft wings, pressure vessels, and storage tanks. Here, we present a method for optimally designing the locations and dimensions of rectangular ribs to reinforce a panel. The work presented here is an extension to our previous work to design structures made solely of discrete plate elements. The most important feature of our method is that the explicit geometry representation provides a direct translation to a computer-aided design (CAD) model, thereby producing reinforcement designs that conform to available plate cutting and joining processes. The main contributions of this paper are the introduction of two important design and manufacturing constraints for the optimal rib layout problem. One is a constraint on the minimum separation between any two ribs to guarantee adequate weld gun access. The other is a constraint that guarantees that ribs do not interfere with holes in the panel. These holes may be needed to, for example, route components or provide access, such as a manhole. We present numerical examples of our method under different types of loadings to demonstrate its applicability.

A Geometry Projection Method for the Optimal Design of Panel Reinforcements With Ribs Made of Plates

2016 ◽  
Author(s):  
Shanglong Zhang ◽  
Julián A. Norato
Keyword(s):  
Optimization Methods ◽  
Pressure Vessels ◽  
Density Field ◽  
Uniform Grid ◽  
Constant Thickness ◽  
Aircraft Wings ◽  
Ship Hulls ◽  
Gradient Based ◽  
Reinforcing Ribs ◽  
Reinforcement Design

The stiffness of plate structures can be significantly improved by adding reinforcing ribs. In this paper, we are in particular concerned with stiffening of panels using ribs made of constant-thickness plates that may be, for example, welded to the panel. These ribs are common in, for example, the reinforcement of ship hulls, aircraft wings, pressure vessels and storage tanks. Existing methods either produce rib designs that cannot be fabricated with plates, or employ heuristics that produce non-optimal designs. This paper presents a method for optimally designing the topology, locations and dimensions of rectangular ribs to reinforce a panel. To this end, we smoothly project an analytic, explicit geometry representation of a set of ribs onto a continuous density field over a design envelope. This density field is discretized in an element-wise manner on a uniform grid for analysis. The initial design consists of a prescribed set of ribs, constrained to remain perpendicular to the panel to facilitate manufacturing and joining of the ribs. The advantages of our method are two-fold. On one hand, as in classical density-based topology optimization, we circumvent re-meshing by using a fixed finite element grid for the analysis, and the differentiability of the projection allows us to employ efficient and robust gradient-based optimization methods. On the other hand, the explicit geometry representation provides a direct translation into CAD, it produces reinforcement designs that conform to available plate cutting and joining processes, and it allows us to impose a constraint on the minimum separation between any two ribs to guarantee clear gaps for weld gun access. Also, bounds on the ribs dimensions can be naturally and directly accommodated. We present numerical examples of our panel reinforcement design under different types of loadings to demonstrate the applicability of the proposed method.

Stresses in Pressurized Circular Shells With Discontinuities, With or Without Stiffeners

1972 ◽  
Vol 16 (02) ◽  
pp. 140-147
Author(s):  
A. J. Durelli ◽  
V. J. Parks
Keyword(s):  
Experimental Determination ◽  
Mechanical Strain ◽  
Three Dimensional ◽  
Pressure Vessels ◽  
Circular Cylinders ◽  
Constant Thickness ◽  
Strain Gages ◽  
Circular Holes ◽  
Reinforcing Ribs

This paper is a summary of a series of five research programs dealing with the experimental determination of stresses, strains, and displacements in circular cylinders subjected to pressure. The vessels have either constant thickness or transverse reinforcing ribs. Circular holes, with either plain or reinforced edges, are located in different positions of the vessels. The methods used for the analysis are: brittle coatings, three-dimensional photoelasticity ("freezing" technique), and electrical and mechanical strain gages. The most important results are summarized in a table. These results will be of interest to designers of underwater ships and of pressure vessels in general.

Minicomputer as a circuit-design tool

SIMULATION ◽  
1972 ◽  
Vol 18 (2) ◽  
pp. 47-56 ◽  
Author(s):  
Zvonko Fazarinc
Keyword(s):  
Circuit Design ◽  
Computer Aided Design ◽  
Design Tool ◽  
Nonlinear Networks ◽  
Long Term Stability ◽  
Processing Cost ◽  
Aided Design ◽  
And Storage ◽  
High Processing

Lack of interactive capabilities and high processing cost are two main areas of complaints directed against the existing implementations of computer- aided-design packages. The minicomputer promises to remove these serious deficiencies despite its speed and storage limitations. The economics and techniques of interactive minicomputer applications are explored and an integration formula suitable for minicomputer implementation is devised. Several nonlinear networks simulated on a minicomputer are used to demonstrate the long-term stability of the formula.

Modernization of Pressure Vessel Design Codes ASME Section VIII, Division 2, 2007 Edition

2007 ◽  
Vol 129 (4) ◽  
pp. 754-758
Author(s):  
T. P. Pastor ◽  
D. A. Osage
Keyword(s):  
Pressure Vessel ◽  
Computer Aided Design ◽  
Pressure Vessels ◽  
Ease Of Use ◽  
Design Codes ◽  
Section Viii ◽  
Special Rules ◽  
The 1960S ◽  
Aided Design ◽  
Division 2

The technology for pressure equipment design continues to advance each and every day. The ASME Boiler and Pressure Vessel Code has been keeping pace with these advances over the last 92 years. As far back as the 1960s, it was recognized that the special requirements for design of pressure vessels operating at pressures over 2000 psi (13.7 MPa) called for special rules, and ASME issued Sec. VIII, Division 2 of Alternative Rules for Pressure Vessels. Since that time, the understanding of failure mechanisms and advances in material science, nondestructive testing, and computer-aided design has progressed to the stage where a new approach was needed not only in the content of design codes but in the way they are presented and organized. This paper introduces the newly issued ASME Sec. VIII, Division 2 of 2007 edition and explores the technical concepts included and the new format designed for ease of use. Included are results of test exercises sponsored by ASME giving actual applications of the new Code for design of vessels. This paper demonstrates ASME’s commitment to provide manufacturers and users of pressure equipment with the most up-to-date technology in easy to use standards that service the international market.

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