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.

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.

Thermal Robustness Assessment of a Rigidized Space Inflatable Boom via Experimental Modal Analysis and Finite Element Modeling

2010 ◽  
Author(s):  
Matthew Daly ◽  
Armaghan Salehian ◽  
Alireza Doosthoseini
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Frequency Response Function ◽  
Good Accuracy ◽  
Natural Frequencies ◽  
Beam Theory ◽  
Element Model ◽  
Modal Testing ◽  
Environmental Temperatures ◽  
Robustness Assessment

The following paper presents the results of a thermal robustness assessment of a rigidized space inflatable boom. Modal testing is performed at three different environmental temperatures; spanning a range of 38°C, with the purpose of characterizing dynamic behavior and assessing changes in bending frequencies. Experimental results show that the natural frequencies of the boom shift only marginally within the tested bandwidth. A finite element model is developed in parallel with experiments to determine compatibility with beam theory. The resulting simulation shows that linear beam theory can be used to predict bending frequencies and frequency response function magnitudes with very good accuracy.

Prestressed Time-Limited Aging Analyses of Concrete Containment Structure

2017 ◽  
Author(s):  
Dahua Cai ◽  
Yonghuan Wang ◽  
Jiangtao Zhang ◽  
Lin Yang ◽  
Hua Rong ◽  
...  
Keyword(s):  
Finite Element ◽  
Numerical Model ◽  
Finite Element Model ◽  
Prestressed Concrete ◽  
Element Model ◽  
Test Results ◽  
Prestress Loss ◽  
Pressure Test ◽  
Key Factor ◽  
Over Time

For prestressed concrete containment structure, prestress loss is a key factor that affects the performance of containment structure. Therefore, prestressed time-limited aging analysis (TLAA) is essential for containment structures. The main objective of prestressed TLAA is to assess the safety of containment structures after prestress loss occurred over time. This paper takes the in-service containment structure as an example to investigate the method of TLAA for grounted prestressed containment structure. Firstly, it introduces methods for prestressed TLAA. Secondly, a finite element model of containment structure is established to calculate the minimum required value (MRV) of prestress. The numerical model is verified by the pressure test results. Thirdly, prestress loss of tendons is calculated. Finally, the residual prestress of tendons are compared with the MRV of prestress to confirm whether the containment can service in a certain period. This study can provide guidance for goouted prestressed TLAA of containment structures.

A development of a Finite Element Model, based in a novel beam theory

2008 ◽  
Author(s):  
Mauro Luis Ramalho Sanches ◽  
Sérgio Frascino Müller de Almeida
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Beam Theory ◽  
Element Model ◽  
Model Based

Vibration Model Construction of the CNC Embroidery Machine Based on the Timoshenko Beam Theory and its Experimental Research

2012 ◽  
Vol 522 ◽  
pp. 593-597
Author(s):  
Peng Li ◽  
Li Zhi Gu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Timoshenko Beam ◽  
Optimization Design ◽  
Production Efficiency ◽  
Technological Development ◽  
Beam Theory ◽  
Element Model ◽  
Timoshenko Beam Theory ◽  
Vibration Model

With its technological development, the CNC embroidery machine rotational speed has increased dramatically. Consequent vibration and noise increase the disconnection rate in the embroidery process and affect the embroidery quality and production efficiency. To solve such problem, by analyzing the vibration causes and comparing the different characteristics of the Timoshenko beam and the Euler-Benouli simply supported beam, the current study indicated the limitation of the traditional vibration analysis method---the widely-used Euler-Bernouli simple beam theory, and constructed a vibration model based on the Timoshenko beam theory. Then a finite element model of the embroidery machine beam was built S and the corresponding experiment were done. Results from the constructed mechanical, mathematical model, and the ANSYS finite element model were compared. It has been verified that the constructed models are consistent with experiment results and that vibration models are constructed reasonably and feasibly. According to these models, the key parameters affecting the beam vibration are identified to work out more accurate and effective structure optimization design and prediction.

Convergence studies of finite element model for analysis of steel-concrete composite beam using a higher-order beam theory

Structures ◽  
2020 ◽  
Vol 27 ◽  
pp. 2025-2033
Author(s):  
Md. Alhaz Uddin ◽  
Majed Abdulrahman Alzara ◽  
Noor Mohammad ◽  
Ahmed Yosri
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Composite Beam ◽  
Beam Theory ◽  
Element Model ◽  
Higher Order

Application of Finite Element in Accurate Calculations of Stresses in Expansion Joints

2018 ◽  
Author(s):  
Sudip Ganguly
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Stress Analysis ◽  
Mechanical Design ◽  
Joint Stiffness ◽  
Beam Theory ◽  
Element Model ◽  
Thick Wall ◽  
Expansion Joint ◽  
Expansion Joints

In order to evaluate the stiffness and perform detailed stress analysis of thick wall flange and flued expansion joint, a computer program based on finite element method was developed in C++, using 8-node axisymmetric element. Traditionally the analysis of expansion joints had been performed using the plate and beam theory which had several limitations and lead to inaccurate estimation of expansion joint stiffness and stresses. In this paper, initially the finite element mathematical model will be discussed, followed by comparison of the results of the stiffness calculations and stress analysis from the past method and that of the above-mentioned finite element model, and finally summarized by some discussions on the dependency of the accuracy of the results on the mesh density of the finite element model. The aforementioned finite element engine would be integrated to the pressure vessel and heat exchanger mechanical design software, AutoPIPE Vessel in the near future.

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