A Synthesis of Aluminum Crewboat Structural Design

1982 ◽  
Vol 19 (01) ◽  
pp. 52-72
Author(s):  
William A. Henrickson ◽  
John S. Spencer
Keyword(s):  
Structural Design ◽  
Beam Theory ◽  
Coast Guard ◽  
Observation Data ◽  
Plate Girders ◽  
Worked Example ◽  
Theory Versus ◽  
Grillage Analysis ◽  
Design Stress

The need exists for a simplified structural review guide to enable U.S. Coast Guard marine inspectors to verify the structural adequacy of aluminum crewboats. The authors have developed such a guide. Typical existing crewboat forms and service speeds have been used to reduce the determination of impact pressures to a function of length and displacement. A design stress limit for the cyclic loading of the bottom structure has been determined based on wave observation data. Plating design has been verified by a comparison of sizing by beam theory versus elastoplastic analysis. A simplified grillage analysis has been used to determine the level of support provided by longitudinal plate girders or keelsons. A worked example and tables of section moduli for typical extrusions attached to plating are included as appendices.

scholarly journals Determination of the order of fractional derivative for subdiffusion equations

2020 ◽  
Vol 23 (6) ◽  
pp. 1647-1662
Author(s):  
Ravshan Ashurov ◽  
Sabir Umarov
Keyword(s):  
Fractional Derivative ◽  
Fixed Time ◽  
Time Instant ◽  
Observation Data ◽  
Additional Information ◽  
Fractional Modeling ◽  
Time Fractional Derivative ◽  
The Right ◽  
Right Order

Abstract The identification of the right order of the equation in applied fractional modeling plays an important role. In this paper we consider an inverse problem for determining the order of time fractional derivative in a subdiffusion equation with an arbitrary second order elliptic differential operator. We prove that the additional information about the solution at a fixed time instant at a monitoring location, as “the observation data”, identifies uniquely the order of the fractional derivative.

Research and Application of High-Efficiency Multi-Cyclone Dust Removal

2011 ◽  
Vol 109 ◽  
pp. 400-404
Author(s):  
Yan Hong Yang ◽  
Da Fu Ni
Keyword(s):  
Structural Design ◽  
High Efficiency ◽  
Dust Removal ◽  
Working Principle ◽  
Selection Of

Performance and working principle of high-efficiency multi-cyclone were analyzed, and the structural design shortage of original high-efficiency multi-cyclone was pointed out. Its structure was researched and designed, including determination of setting chamber and pipe number, selection of material and the design of cyclones.

Determination of transverse flexural and shear moduli of chopped carbon fiber tape-reinforced thermoplastic by vibration

2017 ◽  
Vol 52 (3) ◽  
pp. 395-404
Author(s):  
Xiuqi Lyu ◽  
Jun Takahashi ◽  
Yi Wan ◽  
Isamu Ohsawa
Keyword(s):  
Carbon Fiber ◽  
Beam Theory ◽  
Transversely Isotropic ◽  
High Volume ◽  
Bending Test ◽  
Thermoplastic Material ◽  
Shear Moduli ◽  
High Volume Production ◽  
Volume Production

Chopped carbon fiber tape-reinforced thermoplastic material is specifically developed for the high-volume production of lightweight automobiles. With excellent design processability and flexibility, the carbon fiber tape-reinforced thermoplastic material is manufactured by compressing large amounts of randomly oriented, pre-impregnated unidirectional tapes in a plane. Therefore, the carbon fiber tape-reinforced thermoplastic material presents transversely isotropic properties. Transverse shear effect along the thickness direction of carbon fiber tape-reinforced thermoplastic beam has a distinct influence on its flexural deformation. Accordingly, the Timoshenko beam theory combined with vibration frequencies was proposed to determine the set of transverse flexural and shear moduli. Meanwhile, the transverse flexural and shear moduli of carbon fiber tape-reinforced thermoplastic beam were finally determined by fitting all the first seven measured and calculated eigenfrequencies with the least squares criterion. In addition, the suggested thickness to length ratio for the 3-point bending test and Euler–Bernoulli model was given.

Tension-Leg Platform Design: Interaction of Naval Architectural and Structural Design Considerations

1979 ◽  
Vol 16 (04) ◽  
pp. 343-352
Author(s):  
Cuneyt Capanoglu
Keyword(s):  
Structural Design ◽  
Tension Leg Platform ◽  
Design Considerations ◽  
Exploration And Production ◽  
Anchoring System ◽  
Successful Design ◽  
Exciting Forces ◽  
Platform System ◽  
Selection Of

As oil exploration and production move into water depths over 1000 ft (305 m), several companies are investigating compliant structures as possible solutions to the economic and engineering problems involved. This paper focuses on the tension-leg type of platform, a positively buoyant structure kept on location by a pretensioned anchoring system. The basic approach to design of a tension-leg platform system, the various components of the system and the interaction between naval architectural and structural design considerations are presented. The author points out that planning for a successful design must include:preparation of good design criteria,determination of variables,evaluation of variables for sensitivity and interaction,accurate and timely engineering decisions in selection of a set of parameters, andparallel studies covering fabrication, transportation and installation requirements. Appendices give the mathematical bases for computing motions of the tenslon-leg platform and graphic illustrations of platform characteristics and the effects of typical exciting forces.

scholarly journals Generation of R-Curve from 4ENF Specimens: An Experimental Study

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
V. Alfred Franklin ◽  
T. Christopher
Keyword(s):  
Composite Materials ◽  
Fracture Energy ◽  
Epoxy Composite ◽  
Beam Theory ◽  
Fiber Direction ◽  
Crack Growth Resistance Curve ◽  
Aerospace Applications ◽  
Delamination Toughness ◽  
Theory Solution

The experimental determination of the resistance to delamination is very important in aerospace applications as composite materials have superior properties only in the fiber direction. To measure the interlaminar fracture toughness of composite materials, different kinds of specimens and experimental methods are available. This article examines the fracture energy of four-point end-notched flexure (4ENF) composite specimens made of carbon/epoxy and glass/epoxy. Experiments were conducted on these laminates and the mode II fracture energy, GIIC, was evaluated using compliance method and was compared with beam theory solution. The crack growth resistance curve (R-curve) for these specimens was generated and the found glass/epoxy shows higher toughness values than carbon/epoxy composite. From this study, it was observed that R-curve effect in 4ENF specimens is quite mild, which means that the measured delamination toughness, GIIC, is more accurate.

An Efficient Direct Calculation Approach for Fatigue Assessment of Container Ships Concerning Bending and Warping Stresses

2014 ◽  
Author(s):  
Zhiyuan Li ◽  
Wengang Mao ◽  
Jonas W. Ringsberg
Keyword(s):  
Beam Theory ◽  
Direct Calculation ◽  
Fe Analysis ◽  
Hydrodynamic Simulation ◽  
Fatigue Assessment ◽  
Hull Girder ◽  
Torsional Loads ◽  
Warping Stress

Container ships are particularly susceptible to torsional loads. The distribution of torsion-induced warping stress in a container ship hull is more complicated and difficult to be expressed by beam theory formulas. In practice, finite element (FE) analysis is typically used to calculate the stress response to wave-loading conditions. However, it is time consuming to compute hull girder stresses for all relevant sea conditions through FE analyses. In this paper, an efficient and robust approach is proposed by combining beam theory and FE analyses in the determination of hull girder stresses. The parameters required by beam theory can be regressed through matching stress records from a FE analysis with the corresponding sectional and pressure loads from the hydrodynamic simulation. Stress records obtained using the proposed method are utilized in fatigue assessment of a case study container vessel. The results show that the accuracy of the regression approach is satisfactory compared with the full FE analyses.

scholarly journals GBT-Based Buckling Analysis Using the Exact Element Method

2017 ◽  
Vol 17 (10) ◽  
pp. 1750125 ◽  
Author(s):  
Rui Bebiano ◽  
Moshe Eisenberger ◽  
Dinar Camotim ◽  
Rodrigo Gonçalves
Keyword(s):  
Finite Elements ◽  
Beam Theory ◽  
Computational Effort ◽  
Power Series Method ◽  
Half Wave ◽  
Governing Differential Equation ◽  
Exact Element Method ◽  
Deformation Modes ◽  
Element Method

Generalized Beam Theory (GBT), intended to analyze the structural behavior of prismatic thin-walled members and structural systems, expresses the member deformed configuration as a combination of cross-section deformation modes multiplied by the corresponding longitudinal amplitude functions. The determination of the latter, usually the most computer-intensive step of the analysis, is almost always performed by means of GBT-based conventional 1D (beam) finite elements. This paper presents the formulation, implementation and application of the so-called “exact element method” in the framework of GBT-based linear buckling analyses. This method, originally proposed by Eisenberger (1990), uses the power series method to solve the governing differential equation and obtains the buckling eigenvalue problem from the boundary terms. A few illustrative numerical examples are presented, focusing mainly on the comparison between the combined accuracy and computational effort associated with the determination of buckling solutions with the exact and standard GBT-based (finite) elements. This comparison shows that the GBT-based exact element method may lead to significant computational savings, particularly when the buckling modes exhibit larger half-wave numbers.

Determination of solid Earth tide phase lag by satellite observation data

1999 ◽  
Vol 44 (5) ◽  
pp. 459-461
Author(s):  
Bin Wu ◽  
Yaozhong Zhu ◽  
Bibo Peng
Keyword(s):  
Solid Earth ◽  
Earth Tide ◽  
Satellite Observation ◽  
Observation Data ◽  
Phase Lag ◽  
Solid Earth Tide

Module-Based Static Structural Design of a Modular Reconfigurable Robot

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Richard Phillip Mohamed ◽  
Fengfeng (Jeff) Xi ◽  
Allan Daniel Finistauri
Keyword(s):  
Structural Design ◽  
Design Method ◽  
Optimal Solution ◽  
Local Deformation ◽  
Design Stage ◽  
Coordinate Frame ◽  
Reconfigurable Robots ◽  
Nonlinear Approach ◽  
Reconfigurable Robot

In this paper, the structural design of modular reconfigurable robots (MRRs) is studied. This problem is defined as the determination of proper module sizes according to the robot’s payload and end-effector deflection specifications. Because an MRR has multiple configurations, a simple design process is proposed in order to avoid performing the structural design stage at each configuration. The final structural design is only carried out at a single configuration that can guarantee the robot’s satisfactory performance for all remaining feasible configurations. It is shown that the module structural design stage can be performed at the local coordinate frame of each module. While the module local force requirement can be fully determined, the determination of the module local deformation requirement is redundant. Thus, there can exist multiple design solutions. To overcome this problem, a nonlinear approach using a genetic algorithm is used to search for an optimal solution. Finally, a design simulation is performed on an example MRR, and the results show the effectiveness of the proposed design method.

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