Analysis of Global Load Effects in Catamarans

2002 ◽  
Vol 46 (02) ◽  
pp. 81-91
Author(s):  
Svein Erling Heggelund ◽  
Torgeir Moan
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Beam Theory ◽  
Element Model ◽  
Design Stage ◽  
Reasonable Accuracy ◽  
Torsional Loading ◽  
Prismatic Beam ◽  
Load Effects ◽  
Longitudinal Bending

Relevant stresses and deformations resulting from longitudinal bending and torsion are calculated for a 60 m catamaran by a global finite-element model. The results are compared with results from prismatic beam theory modified to account for the effect of wide flanges and significant window openings typical for a catamaran hull. It is found that the global stresses are predicted with a reasonable accuracy for the initial design stage. In the present case, the effect of warping on shear stress due to torsional loading is moderate and can be neglected. However, this effect is strongly dependent on the vessel design and can be important for a vessel with narrower hulls and a superstructure that is lower relative to the total height.

Finite Element Analysis of Tire/Rim Interface Forces Under Braking and Cornering Loads

1992 ◽  
Vol 20 (2) ◽  
pp. 83-105 ◽  
Author(s):  
J. P. Jeusette ◽  
M. Theves
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Contact Pressure ◽  
Element Model ◽  
Shear Stresses ◽  
Detailed Knowledge ◽  
Stress Distributions ◽  
Element Analysis ◽  
Plane Shear ◽  
Normal Contact

Abstract During vehicle braking and cornering, the tire's footprint region may see high normal contact pressures and in-plane shear stresses. The corresponding resultant forces and moments are transferred to the wheel. The optimal design of the tire bead area and the wheel requires a detailed knowledge of the contact pressure and shear stress distributions at the tire/rim interface. In this study, the forces and moments obtained from the simulation of a vehicle in stationary braking/cornering conditions are applied to a quasi-static braking/cornering tire finite element model. Detailed contact pressure and shear stress distributions at the tire/rim interface are computed for heavy braking and cornering maneuvers.

Dynamic Behavior of Cellular Materials under Combined Shear-Compression

2016 ◽  
Vol 835 ◽  
pp. 649-653
Author(s):  
Yuan Yuan Ding ◽  
Shi Long Wang ◽  
Zhi Jun Zheng ◽  
Li Ming Yang ◽  
Ji Lin Yu
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Finite Element Model ◽  
Nonlinear Regression ◽  
Element Model ◽  
Cellular Materials ◽  
Regression Method ◽  
Plateau Stress ◽  
Nonlinear Regression Method ◽  
Biaxial Behavior

A 3D cell-based finite element model is employed to investigate the dynamic biaxial behavior of cellular materials under combined shear-compression. The biaxial behavior is characterized by the normal stress and shear stress, which could be determined directly from the finite element results. A crush plateau stress is introduced to illustrate the critical crush stress, and the result shows that the normal plateau stress declines with the increase of the shear plateau stress, which climbs with the increase of loading angle. An elliptical criterion of normal plateau stress vs. shear plateau stress is obtained by the nonlinear regression method.

Optimization Design of Pressure Shell in Underwater Vehicle Based on Response Surface Model

2009 ◽  
Vol 419-420 ◽  
pp. 89-92
Author(s):  
Zhuo Yi Yang ◽  
Yong Jie Pang ◽  
Zai Bai Qin
Keyword(s):  
Finite Element ◽  
Response Surface ◽  
Optimization Design ◽  
Engineering Application ◽  
Element Model ◽  
Response Surface Model ◽  
Design Stage ◽  
Surface Model ◽  
Design Variables ◽  
Structure Strength

Cylinder shell stiffened by rings is used commonly in submersibles, and structure strength should be verified in the initial design stage considering the thickness of the shell, the number of rings, the shape of ring section and so on. Based on the statistical techniques, a strategy for optimization design of pressure hull is proposed in this paper. Its central idea is that: firstly the design variables are chosen by referring criterion for structure strength, then the samples for analysis are created in the design space; secondly finite element models corresponding to the samples are built and analyzed; thirdly the approximations of these analysis are constructed using these samples and responses obtained by finite element model; finally optimization design result is obtained using response surface model. The result shows that this method that can improve the efficiency and achieve optimal intention has valuable reference information for engineering application.

scholarly journals Effect of spatial distribution of fibers on elastic properties of unidirectional carbon/carbon composites

2021 ◽  
Vol 309 ◽  
pp. 01214
Author(s):  
M.V.N Mohan ◽  
Ramesh Bhagat Atul ◽  
Vijay Kumar Dwivedi
Keyword(s):  
Finite Element ◽  
Spatial Distribution ◽  
Elastic Properties ◽  
Element Model ◽  
Experimental Methods ◽  
Design Stage ◽  
Carbon Composites ◽  
Numerical Predictions ◽  
Numerical Finite Element ◽  
Very High

Carbon/Carbon composites finds its applications in several high temperature applications in the field of Space, Aviation etc. Designing of components or sub systems with carbon/carbon composites is a challenging task. It requires prediction of elastic properties with a very high accuracy. The prediction can be normally done by analytical, numerical or experimental methods. At the design stage the designers resort to numerical predictions as the experimental methods are not feasible during design stage. Analytical methods are complex and difficult to implement. The designers use numerical methods for prediction of elastic properties using Finite Element Modeling (FEM). The spatial distribution of fibers in matrix has an effect on results of prediction of elastic constants. The generation of random spatial distribution of fibers in representative volume element (RVE) challenging. The present work is aimed at study of effect of spatial distribution of fiber in numerical prediction of elastic properties of unidirectional carbon/carbon composites. MATLAB algorithm is used to generate the spatial distribution of fibers in unidirectional carbon/carbon composites. The RVE elements with various random fiber distributions are modeled using numerical Finite element Model using ABAQUS with EasyPBC plugin. The predicted elastic properties have shown significant variation to uniformly distributed fibers.

A Numerical Approach for the Prediction and Reduction of Structure-Borne Noise During the Design Stage of Ground Vehicles

1993 ◽  
Author(s):  
Nickolas Viahopoulos ◽  
Edward V. Shalis ◽  
Michael A. Latcha
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Numerical Approach ◽  
Design Stage ◽  
Structural Components ◽  
Ground Vehicles ◽  
Radiated Noise ◽  
Forcing Function ◽  
Military Applications ◽  
Commercial Applications

Abstract During the design stage of ground vehicles it is important to reduce the noise emitted from structural components. In commercial applications the reduction of the interior noise for passenger comfort is a concern with increased significance. In military applications noise radiated from the exterior of the vehicle is of primary importance for the survivability of the vehicle. Numerical acoustic prediction software can be used during the design stage to predict and reduce the radiated noise. Two formulations, the Rayleigh integral equation1 and the direct boundary element method2,3 were implemented into software for acoustic prediction. The developed code can accept information from a finite element model with a known input forcing function. Specifically, the predicted velocities on the structural surfaces can be used as input to the acoustic code for predicting the noise emitted from a vibrating structure. Computation of acoustic sensitivities4 was also implemented in the code. This information can identify the portions of the boundary that effect the radiated noise most, and it can be used in an optimization process to reduce the noise radiated from a vibrating structure.

A finite element model to study the effect of porosity location on the elastic modulus of a cantilever beam

2019 ◽  
Vol 43 (4) ◽  
pp. 443-453
Author(s):  
Stephen M. Handrigan ◽  
Sam Nakhla
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Focused Ion Beam ◽  
Mechanical Response ◽  
Ion Beam ◽  
Three Dimensional ◽  
Beam Theory ◽  
Element Model ◽  
Fe Model ◽  
Three Dimensional Finite Element

An investigation to determine the effect of porosity concentration and location on elastic modulus is performed. Due to advancements in testing methods, the manufacturing and testing of microbeams to obtain mechanical response is possible through the use of focused ion beam technology. Meanwhile, rigorous analysis is required to enable accurate extraction of the elastic modulus from test data. First, a one-dimensional investigation with beam theory, Euler–Bernoulli and Timoshenko, was performed to estimate the modulus based on load-deflection curve. Second, a three-dimensional finite element (FE) model in Abaqus was developed to identify the effect of porosity concentration. Furthermore, the current work provided an accurate procedure to enable accurate extraction of the elastic modulus from load-deflection data. The use of macromodels such as beam theory and three-dimensional FE model enabled enhanced understanding of the effect of porosity on modulus.

A SPECTRAL/hp NONLINEAR FINITE ELEMENT ANALYSIS OF HIGHER-ORDER BEAM THEORY WITH VISCOELASTICITY

2012 ◽  
Vol 04 (01) ◽  
pp. 1250010 ◽  
Author(s):  
V. P. VALLALA ◽  
G. S. PAYETTE ◽  
J. N. REDDY
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Virtual Work ◽  
Constitutive Relations ◽  
Beam Theory ◽  
Element Model ◽  
Higher Order ◽  
Time Step ◽  
Third Order ◽  
The Third

In this paper, a finite element model for efficient nonlinear analysis of the mechanical response of viscoelastic beams is presented. The principle of virtual work is utilized in conjunction with the third-order beam theory to develop displacement-based, weak-form Galerkin finite element model for both quasi-static and fully-transient analysis. The displacement field is assumed such that the third-order beam theory admits C0 Lagrange interpolation of all dependent variables and the constitutive equation can be that of an isotropic material. Also, higher-order interpolation functions of spectral/hp type are employed to efficiently eliminate numerical locking. The mechanical properties are considered to be linear viscoelastic while the beam may undergo von Kármán nonlinear geometric deformations. The constitutive equations are modeled using Prony exponential series with general n-parameter Kelvin chain as its mechanical analogy for quasi-static cases and a simple two-element Maxwell model for dynamic cases. The fully discretized finite element equations are obtained by approximating the convolution integrals from the viscous part of the constitutive relations using a trapezoidal rule. A two-point recurrence scheme is developed that uses the approximation of relaxation moduli with Prony series. This necessitates the data storage for only the last time step and not for the entire deformation history.

The role of bending stress on the initiation of reverse transverse defects

2020 ◽  
Vol 235 (1) ◽  
pp. 61-72
Author(s):  
Soumyajit Mojumder ◽  
Hang Su ◽  
Cong Qiu ◽  
Peter Mutton ◽  
Aparna Singh ◽  
...  
Keyword(s):  
Finite Element ◽  
Iron Ore ◽  
Maximum Stress ◽  
Load Ratio ◽  
Element Model ◽  
Bending Stress ◽  
Vertical Load ◽  
Lower Head ◽  
Longitudinal Bending

This paper investigated the role of longitudinal reverse bending stress on the initiation of reverse transverse defects. The longitudinal reverse bending stress occurs due to the reverse bending of the rail between two-wheel passage leading to the generation of tensile bending stress at the railhead and the lower head areas. The longitudinal bending stress was investigated as part of a parametric study on the rail cant angle, rail stiffness, lateral-to-vertical load ratio, and rail profile. A finite element model was created by using ABAQUS to analyze the extent of reverse bending in rails with respect to the chosen set of parameters. Under different lateral-to-vertical load ratios of 0, 0.3, 0.5, and 0.7, the maximum stress at the rail lower gauge corner was found to vary between 14.57MPa and 15.47MPa under the reverse bending condition. Similarly, low values of tensile stress under the reverse bending scenario were observed with changes in the rail cant angle and axle spacing with respect to different coal and iron ore wagons. The results revealed that the magnitude of the bending stress under different conditions of reverse bending was not significant enough to initiate a crack at the lower gauge corner.

Optical-Fiber and Entry-Cone Contact Stresses

1998 ◽  
Vol 531 ◽  
Author(s):  
J. M. Anderson ◽  
J. F. Malluck ◽  
M. M. Tabaddo ◽  
C. K. Sidbury ◽  
T. E. McNeil
Keyword(s):  
Finite Element ◽  
Optical Fiber ◽  
Finite Element Model ◽  
Beam Theory ◽  
Element Model ◽  
Contact Stresses ◽  
Local Stresses ◽  
Over Time ◽  
Neighborhood Stress

AbstractMany of the broken fibers in optical connectors, especially those that seem to occur over time without apparent provocation are found in the ferrule at the transition from entry cone to alignment capillary. This paper contends that many such breaks are due to local stresses caused by debris or some other relatively rigid imperfection in the transition neighborhood. Stress estimates from beam theory and from a finite-element model are presented along with some indirect experimental observations supporting the contention.

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