A Finite Element Model for Predicting Time-Dependent Deformations and Damage Accumulation in Laminated Composite Bolted Joints

1999 ◽  
Vol 33 (9) ◽  
pp. 794-826 ◽  
Author(s):  
Alan R. Kallmeyer ◽  
Ralph I. Stephens
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Damage Accumulation ◽  
Laminated Composite ◽  
Element Model ◽  
Bolted Joints ◽  
Time Dependent

Vibration and Sound Radiation Characteristics of Composite Flat-Panel Sound Radiator

2013 ◽  
Vol 431 ◽  
pp. 177-181
Author(s):  
C.H. Jiang ◽  
T.Y. Kam
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Response Spectrum ◽  
Sound Radiation ◽  
Laminated Composite ◽  
Element Model ◽  
Flat Panel ◽  
Radiation Characteristics ◽  
Experimental Approaches ◽  
Vibration And Sound Radiation

The vibration and sound radiation characteristics of laminated composite flat-panel sound radiators are studied via both theoretical and experimental approaches. In the theoretical study, a finite element model is presented to formulate the forced vibration of the sound radiators. The first Rayleigh integral is used to construct the sound pressure level curve of the sound radiators. In the experimental study, a laminated composite sound radiator was subjected to sweep sine excitation to determine the frequency response spectrum from which the natural frequencies of the sound radiator were identified. The sound radiator with salt powder distributed on its top surface was excited to generate the vibration shapes of the sound radiator at several selected frequencies. The SPL curve of the sound radiator was also measured experimentally. The experimental results are then used to verify the feasibility and accuracy of the proposed finite element model.

Finite-Element Simulations and Probabilistic Fracture Assessments of the Response of Alternate Rifling Geometries

2007 ◽  
Author(s):  
A. E. Segall ◽  
R. Carter
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Thermal Stresses ◽  
Rotational Symmetry ◽  
Element Model ◽  
Time Dependent ◽  
Uniform Heating ◽  
Thermal Pressure ◽  
Single Firing ◽  
Hoop Stresses

A 3-D finite-element model was used to simulate the severe and localized thermal/pressure transients and the resulting stresses experienced by a rifled ceramic-barrel with a steel outer-liner; the focus of the simulations was on the influence of non-traditional rifling geometries on the thermoelastic- and pressure-stresses generated during a single firing event. In order to minimize computational requirements, a twisted segment of the barrel length based on rotational symmetry was used. Using this simplification, the model utilized uniform heating and pressure across the ID surface via a time-dependent convective coefficient and pressure generated by the propellant gasses. Results indicated that the unique rifling geometries had only a limited influence on the maximum circumferential (hoop) stresses and temperatures when compared with more traditional rifling configurations because of the compressive thermal stresses developed at the heated (and rifled) surface.

scholarly journals Active Constrained Layer Damping of Smart Skew Laminated Composite Plates Using 1–3 Piezoelectric Composites

2013 ◽  
Vol 2013 ◽  
pp. 1-17 ◽  
Author(s):  
R. M. Kanasogi ◽  
M. C. Ray
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Laminated Composite ◽  
Composite Plates ◽  
Element Model ◽  
Constrained Layer Damping ◽  
Laminated Composite Plates ◽  
Piezoelectric Composites ◽  
Active Constrained Layer Damping ◽  
Active Constrained Layer

This paper deals with the analysis of active constrained layer damping (ACLD) of smart skew laminated composite plates. The constraining layer of the ACLD treatment is composed of the vertically/obliquely reinforced 1–3 piezoelectric composites (PZCs). A finite element model has been developed for accomplishing the task of the active constrained layer damping of skew laminated symmetric and antisymmetric cross-ply and antisymmetric angle-ply composite plates integrated with the patches of such ACLD treatment. Both in-plane and out-of-plane actuations by the constraining layer of the ACLD treatment have been utilized for deriving the finite element model. The analysis revealed that the vertical actuation dominates over the in-plane actuation. Particular emphasis has been placed on investigating the performance of the patches when the orientation angle of the piezoelectric fibers of the constraining layer is varied in the two mutually orthogonal vertical planes. Also, the effects of varying the skew angle of the substrate laminated composite plates and different boundary conditions on the performance of the patches have been studied. The analysis reveals that the vertically and the obliquely reinforced 1–3 PZC materials should be used for achieving the best control authority of ACLD treatment, as the boundary conditions of the smart skew laminated composite plates are simply supported and clamped-clamped, respectively.

scholarly journals ACCOUNTING FOR EFFECTS OF DECREASING BOND BETWEEN CONCRETE AND REBARS ON SEISMIC RESISTANCE OF REINFORCED CONCRETE STRUCTURAL ELEMENTS

2005 ◽  
Vol 11 (3) ◽  
pp. 163-168
Author(s):  
Andrey V. Benin
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Finite Element Model ◽  
Functional Dependence ◽  
Element Model ◽  
Strain Ratio ◽  
Time Dependent ◽  
Strain Diagram ◽  
System Components ◽  
Non Linear

This study reviews an alternative of reinforced concrete finite element model as a system, where physical conditions for system components are recorded independently and, in addition, conditions for interaction of system components on their contact are also introduced. In this case, we are able to take into account all specific features of reinforcement, to trace the history of loading and destruction for each rebar. Basic specific feature of reviewed problem ascertains the necessity to use non‐linear stress‐strain ratio in reinforced concrete with consideration of specific features of reinforced concrete activity after cracking. Naturally, functional dependence describing this ratio varies along with the progress of rebars corrosion. Exactly, corrosion of rebars is the key reason for time‐dependent quality degrading of reinforced concrete structures. This problem stands for more urgency with respect to structures in seismic sensitive zones since such corrosion of rebars leads to deviations of the structure rigidity characteristics and, in turn, it may lead to an reduction of bearing capability in certain elements or to an increase of displacements to intolerable high values. This study proposes a clarified procedure to solve plane‐stressed problem for reinforced concrete. The specific feature of this procedure assumes an application of new approximation for non‐linear concrete strain diagram, development of a detailed finite element model for reproduction of effect generated under concrete/rebar bond forces, as well as such considerable time‐dependent factors as concrete creep and rebar corrosion.

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