Effects of Rotation of Material Axes on Free Flexural Vibrations of Centrally Bonded Symmetric Double Doubler Joint in Composite Mindlin Plates or Panels

2011 ◽  
Author(s):  
U. Yuceoglu ◽  
O. Gu¨vendik
Keyword(s):  
Boundary Value Problem ◽  
Dynamic Equations ◽  
Moments Of Inertia ◽  
Adhesive Layers ◽  
Plate Elements ◽  
System 2 ◽  
Support Conditions ◽  
Effects Of Rotation ◽  
Interpolation Polynomials ◽  
System 1

The present study investigates the serious effects of rotation of material axes on the free dynamic response of composite plates or panels with “Bonded Double Doubler Joint Systems”. The “Plate Adherends” and the “Upper and Lower Doubler Plates” are connected through the relatively very thin adhesive layers. The “Bonded Double Doubler Joint System” is considered in terms of the “System.1” and the “System.2”. In the “System.1”, the material directions of “Plate Adherends” are rotated 90° (about z-axis) while there is no change in the material axes of the “Double Doubler Plates”. In the “System.2”, the material directions of the “Double Doubler Plates” are rotated 90° (about z-axis), while there is no change in the material axes of the “Plate Adherends”. All plate elemnts of the “System.1” and the “System.2” are assumed to be dissimilar “Orthotropic Mindlin Plates” with the transverse shear deformations and the transverse (or bending) moments of inertia and the rotary moments of inertia. The upper and lower adhesive layers are linearly elastic continua with dissimilar material properties and with unequal thicknesses. The damping effects in all plate elements and also in adhesive layers are neglected. The entire theoretical analysis for both “Systems.1 and 2” is based on the “Orthotropic Mindlin Plate Theory”. For this purpose, the dynamic equations of the left and the right “Plate adherends” and of the “Upper and Lower Doubler Plates” and the equations of the adhesive layers are combined to-gather with the stress resultant – displacement expressions of the plate elements. Then, after some algebric manipulations and combinations, and with the “Classical Levy’s Solutions” the original dynamic equations are finally reduced into the two new sets of the “Governing System of the First Order O.D.E’s” in compact matrix forms with the “state vectors” for the “System.1” and “System.2”, respectively. In this way, the original “Initial and Boundary Value Problem” (or the free vibrations problem) is converted to the “Multi–Point Boundary Value Problem” of Mechanics and Physiscs. In the case of both “Systems.1 and 2”, these results facilitate the direct application of the present method of solution that is the “Modified Transfer Matrix Method (MTMM) (with Interpolation Polynomials)”. The aforementioned “Governing Equations” for both “Systems.1 and 2” are numerically integreted by making use of the “ (MTMM) (with Interpolation Polynomials)”. Thus, the natural frequencies and the mode shapes of the “Systems.1” and the “System.2” are graphically presented for the same “Support Conditions”. The comparison of the numerical results corresponding to each “System.1” and “System.2” for the same “Support Conditions” is considered leading to some very important conclusions.

Rotation of Material Axes Effects on Free Bending Vibrations Response of Composite Mindlin Base Plates or Panels Stiffened by Three Bonded Plate Strips

2011 ◽  
Author(s):  
U. Yuceoglu ◽  
J. Javanshir ◽  
T. Farsadi ◽  
O¨. Gu¨vendik
Keyword(s):  
Base Plate ◽  
Mode Shapes ◽  
Mindlin Plate ◽  
Governing Equations ◽  
Bending Vibrations ◽  
Plate Elements ◽  
System 2 ◽  
Interpolation Polynomials ◽  
System 1 ◽  
Free Bending

In the present study, the rotation of material axes on the free bending vibrations response of a certain type of composite “Bonded and Stiffened System” is theoretically analyzed and numerically solved with some numerical results. The composite “Bonded and Stiffened System” is composed of a “Mindlin Base Plate or Panel” reinforced by three “Bonded Stiffening Plate Strips”. In the analysis, the 90° rotation effects of the material axes on the natural frequencies and the mode shapes of the entire “System” are investigated. The aforementioned “Bonded and Stiffened System” is considered in terms of the “System.1” and the “System.2”. In the “System.1”, the material axes of the “Base Plate” are rotated 90° (about z-axis), while there is no change in the material axes of the “Bonded Plate Strips”. In the “System.2”, there is no change in the material directions of the “Base Plate”, while the material axes of the “Bonded Plate Strips” are rotated 90° degrees. The “Base Plate or Panel” and the three “Bonded Plate Strips” are assumed to be dissimilar “Orthotropic Mindlin Plates”. The in-between, relatively very thin, linearly elastic adhesive layers are considered with different material characteristics. All “Mindlin Plate Elements” of both “Systems.1 and 2” are included in the analysis with the transverse (or bending) moments of inertia and rotary moments of inertia. The dynamic equations of the “Mindlin Plate Elements” and the in-between adhesive layer expressions (with the transverse normal and shear stresses) are combined togather. After some algebraic manipulations and combinations, they are eventually reduced to a set of the “Governing System of the First Order O.D.E’s” in compact matrix forms with the “state vectors” for each case of the “System.1” and “System.2”. The aforementioned “Governing Equations” facilitate direct application of the present method of solution that is the “Modified Transfer Matrix Method (MTMM) (with Interpolation Polynomials)”. The “Governing Equations” are numerically Integrated by means of the “ (MTMM) (with Interpolation Polynomials)”. The natural frequencies and the mode shapes of the “Systems.1 and 2” are computed and graphically presented for some “Support Conditions” of the “Systems” under consideration. The comparison of the numerical results led to some important conclusions.

Effects of Variable Non-Central Locations of Bonded Double Doubler Joint System on Free Flexural Vibrations of Orthotropic Composite Mindlin Plate or Panel Adherents

2012 ◽  
Author(s):  
U. Yuceoglu ◽  
Ö. Güvendik
Keyword(s):  
Natural Frequencies ◽  
Mode Shapes ◽  
Mindlin Plate ◽  
Central Position ◽  
Joint Region ◽  
Joint System ◽  
Adhesive Layers ◽  
Governing System ◽  
Plate Elements ◽  
Interpolation Polynomials

This study investigates the “Effects of Variable Non-Central Locations of Bonded Double Doubler Joint System on Free Flexural Vibrations of Orthotropic Composite Mindlin Plate or Panel Adherents”. The problem is theoretically analyzed and is numerically solved in terms of the natural frequencies and the corresponding mode shapes of the entire “System”. The “Bonded Double Doubler Joint System” and the “Plate of Panel Adherents” are considered as dissimilar “Orthotropic Mindlin Plates”. In all plate elements, the transverse shear deformations and the transverse and rotary moments of inertia are included in the analysis. The relatively very thin adhesive layers in the “Bounded Joint Region” are assumed to be linearly elastic continua with transverse normal and shear deformations. The “damping effects” in the adhesive layers and in all plate elements of the “System” are neglected. The sets of the “Dynamic Mindlin Equations” of both upper and lower “Doubler Plates” and the “Plate or Panel Adherents” and the adhesive layer equations are combined together with the orthotropic stress resultant-displacement expressions resulting in a set of “Governing System of PDE’s” in a “special form”. By making use of the “Classical Levy’s Solutions”, in aforementioned “Governing PDE’s” and following some algebraic manipulations and combinations, the “Governing System of the First Order Ordinary Differential Equations” are obtained in compact “state vector” forms. Thus, the “Initial and Boundary Value Problem” at the beginning is finally converted into a “Multi-Point Boundary Value Problem” of Mechanics (and Physics). These analytical results developed facilitate the present method of solution that is the “Modified Transfer Matrix Method (MTMM) (with Interpolation Polynomials)”. The final set of the “Governing System of ODE’s” is numerically integrated by means of the “MTMM with Interpolation Polynomials”. In this way, the natural frequencies and the mode shapes of the “Bonded System”, depending on the variable non-central location of the “Bonded Double Doubler Joint System” are computed for several sets of the far left and the far right “Boundary Conditions” of the “Orthotropic Plate or Panel Adherents”. It was observed that, based on the numerical results, the mode shapes and their natural frequencies are very much affected by the variable position (or location) of the “Bonded Double Doubler Joint” in the “System”. It was also found that as the “Bonded Double Doubler Joint” moves from the central position in the “System” towards the increasingly non-central position, the natural frequencies (in comparison with those of the central position) changes, respectively. The highly-stiff “Bonded Double Doubler Joint Region” becomes “almost stationary” in all modes in “Hard” Adhesive cases.

Free Flexural Vibrations Response of Composite Mindlin Plates or Panels With a Centrally Bonded Symmetric Double Lap Joint (or Symmetric Double Doubler Joint)

2005 ◽  
Author(s):  
U. Yuceoglu ◽  
O. Gu¨vendik ◽  
V. O¨zerciyes
Keyword(s):  
Natural Frequencies ◽  
Mode Shapes ◽  
Solution Technique ◽  
Shear Stresses ◽  
Lap Joint ◽  
Adhesive Layers ◽  
Present Solution ◽  
Flexural Vibrations ◽  
Support Conditions ◽  
Interpolation Polynomials

The present study is concerned with the “Free Flexural Vibrations Response of Composite Mindlin Plates or Panels with a Centrally Bonded Symmetric Double Lap Joint (or Symmetric Double Doubler Joint). The plate “adherends” and the plate “doublers” are considered as dissimilar, orthotropic “Mindlin Plates” with the transverse and the rotary moments of inertia. The relatively, very thin adhesive layers are taken into account in terms of their transverse normal and shear stresses. The mid-center of the bonded region of the joint is at the mid-center of the entire system. In order to facilitate the present solution technique, the dynamic equations of the plate “adherends” and the plate “doublers” with those of the adhesive layers are reduced to a set of the “Governing System of First Order ordinary Differential Equations” in terms of the “state vectors” of the problem. This reduced set establishes a “Two-Point Boundary Value Problem” which can be numerically integrated by making use of the “Modified Transfer Matrix Method (MTMM) (with Interpolation Polynomials)”. In the adhesive layers, the “hard” and the “soft” adhesive cases are accounted for. It was found that the adhesive elastic constants drastically influence the mode shapes and their natural frequencies. Also, the numerical results of some parametric studies regarding the effects of the “Position Ratio” and the “Joint Length Ratio” on the natural frequencies for various sets of support conditions are presented.

scholarly journals Sufficient conditions for hyperbolicity and consistency of the dynamic equations for fluid-saturated solids

2021 ◽  
Author(s):  
Vladimir A. Osinov
Keyword(s):  
Boundary Value Problem ◽  
Wave Speed ◽  
Boundary Value ◽  
Sufficient Conditions ◽  
Positive Definiteness ◽  
Dynamic Equations ◽  
Necessary Condition ◽  
Systems Of Equations ◽  
Acoustic Tensor ◽  
Ill Posed

AbstractPrevious studies showed that the dynamic equations for a porous fluid-saturated solid may lose hyperbolicity and thus render the boundary-value problem ill-posed while the equations for the same but dry solid remain hyperbolic. This paper presents sufficient conditions for hyperbolicity in both dry and saturated states. Fluid-saturated solids are described by two different systems of equations depending on whether the permeability is zero or nonzero (locally undrained and drained conditions, respectively). The paper also introduces a notion of wave speed consistency between the two systems as a necessary condition which must be satisfied in order for the solution in the locally drained case to tend to the undrained solution as the permeability tends to zero. It is shown that the symmetry and positive definiteness of the acoustic tensor of the skeleton guarantee both hyperbolicity and the wave speed consistency of the equations.

scholarly journals Milk Production, Body Weight, Body Condition Score, Activity, and Rumination of Organic Dairy Cattle Grazing Two Different Pasture Systems Incorporating Cool- and Warm-Season Forages

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 264
Author(s):  
Kathryn E. Ritz ◽  
Bradley J. Heins ◽  
Roger D. Moon ◽  
Craig C. Sheaffer ◽  
Sharon L. Weyers
Keyword(s):  
Body Weight ◽  
Milk Production ◽  
Body Condition Score ◽  
Warm Season ◽  
Cool Season ◽  
Organic Dairy ◽  
Condition Score ◽  
Annual Grasses ◽  
System 2 ◽  
System 1

Organic dairy cows were used to evaluate the effect of two organic pasture production systems (temperate grass species and warm-season annual grasses and cool-season annuals compared with temperate grasses only) across two grazing seasons (May to October of 2014 and 2015) on milk production, milk components (fat, protein, milk urea nitrogen (MUN), somatic cell score (SCS)), body weight, body condition score (BCS), and activity and rumination (min/day). Cows were assigned to two pasture systems across the grazing season at an organic research dairy in Morris, Minnesota. Pasture System 1 was cool-season perennials (CSP) and Pasture System 2 was a combination of System 1 and warm-season grasses and cool-season annuals. System 1 and System 2 cows had similar milk production (14.7 and 14.8 kg d−1), fat percentage (3.92% vs. 3.80%), protein percentage (3.21% vs. 3.17%), MUN (12.5 and 11.5 mg dL−1), and SCS (4.05 and 4.07), respectively. Cows in System 1 had greater daily rumination (530 min/day) compared to cows in System 2 (470 min/day). In summary, warm-season annual grasses may be incorporated into grazing systems for pastured dairy cattle.

scholarly journals Comparison of Three Fungicide Spray Advisories for Lettuce Downy Mildew

Plant Disease ◽  
2001 ◽  
Vol 85 (8) ◽  
pp. 895-900 ◽  
Author(s):  
B. M. Wu ◽  
K. V. Subbarao ◽  
A. H. C. van Bruggen ◽  
S. T. Koike
Keyword(s):  
Downy Mildew ◽  
Drip Irrigation ◽  
Leaf Wetness ◽  
Lettuce Downy Mildew ◽  
Advisory System ◽  
System 2 ◽  
Forecasting System ◽  
Low Incidence ◽  
System 1 ◽  
First Time

Lettuce growers in coastal California have relied mainly on protective fungicide sprays to control downy mildew. Thus, timing of sprays before infection is critical for optimal results. A leaf-wetness-driven, infection-based advisory system, previously developed, did not always perform satisfactorily. In this study, the advisory system was modified by incorporating a pathogen survival component (system 1) or both survival and sporulation components (system 2). These systems were then evaluated in commercial lettuce fields in coastal California during 1996-1998. Three or four treatments were carried out in each field: (i) no spray; (ii) sprays as scheduled by the growers; (iii) sprays following modified system 1; and (iv) sprays following the original advisory system (1996) or modified system 2 (1998). Downy mildew incidence was evaluated every 2 to 9 days. In fields with drip irrigation, the number of fungicide applications was reduced by one or two regardless of the advisory system used compared to the grower's calendar-based schedule, although one unnecessary spray was recommended in 1996 at Soledad and 1997 at Salinas. Under all three systems, disease levels were low (incidence <25% and about 1 lesion per plant) for fields with drip irrigation, but not for fields with sprinklers (incidence up to 100% and 5 to 10 lesions per plant). For the first time, we established that survival and sporulation components are not needed for a lettuce downy mildew forecasting system. Instead, a threshold with a shorter period of morning leaf wetness and high temperatures were found to have potential for improving forecasting efficiency.

scholarly journals Performance of deep learning technology for evaluation of positioning quality in periapical radiography of the maxillary canine

2021 ◽  
Author(s):  
Mizuho Mori ◽  
Yoshiko Ariji ◽  
Motoki Fukuda ◽  
Tomoya Kitano ◽  
Takuma Funakoshi ◽  
...  
Keyword(s):  
Deep Learning ◽  
Characteristic Curve ◽  
Classification Performance ◽  
Learning Systems ◽  
Learning Technology ◽  
System 2 ◽  
Potential Benefits ◽  
System 1 ◽  
Periapical Radiography

Abstract Objectives The aim of the present study was to create and test an automatic system for assessing the technical quality of positioning in periapical radiography of the maxillary canines using deep learning classification and segmentation techniques. Methods We created and tested two deep learning systems using 500 periapical radiographs (250 each of good- and bad-quality images). We assigned 350, 70, and 80 images as the training, validation, and test datasets, respectively. The learning model of system 1 was created with only the classification process, whereas system 2 consisted of both the segmentation and classification models. In each model, 500 epochs of training were performed using AlexNet and U-net for classification and segmentation, respectively. The segmentation results were evaluated by the intersection over union method, with values of 0.6 or more considered as success. The classification results were compared between the two systems. Results The segmentation performance of system 2 was recall, precision, and F measure of 0.937, 0.961, and 0.949, respectively. System 2 showed better classification performance values than those obtained by system 1. The area under the receiver operating characteristic curve values differed significantly between system 1 (0.649) and system 2 (0.927). Conclusions The deep learning systems we created appeared to have potential benefits in evaluation of the technical positioning quality of periapical radiographs through the use of segmentation and classification functions.

A New Class of Oxide Superconductor (Nd, Ce, Sr)2CuO4

1989 ◽  
Vol 156 ◽  
Author(s):  
E. Takayama-Muromachi
Keyword(s):  
Crystal Structure ◽  
Crystal Chemistry ◽  
Superconducting Phase ◽  
Type Structure ◽  
Oxide Superconductor ◽  
New Class ◽  
System 2 ◽  
New Type ◽  
System 1 ◽  
Tetragonal Cell

ABSTRACTSince the discovery of the high-Tc superconductor in the La-Ba-Cu-O system [1], a great deal of experimental and theoretical effort have been made to clarify the nature of the Cu-based oxides. In order to elucidate mechanism of the high-Tc superconductivity, discovery of a new type of superconductor is no doubt of great importance. Recently, Akimitsu et al. found a new oxide superconductor in the Nd-Ce-Sr-Cu-O system [2]. Soon after their discovery, the superconducting phase was isolated and identified [3]. It has a tetragonal cell with space group P4/nmm and has a structure closely related to but different from the K2NiF4− or T'-Nd2CuO4− -type structure. Although, Tc of the Nd-Ce-Sr-Cu oxide is not so high (ca. 20 K) compared with the 1–2–3 or Bi(Tl)-based superconductors, it has aroused interest widely due to a very simple crystal structure. In this article, I will discuss superconductivity and crystal chemistry of the Nd-Ce-Sr-Cu oxide. Also, various compounds isostructural to it will be presented.

scholarly journals Three levels of naturalistic knowledge

2019 ◽  
Author(s):  
Andreas Stephens
Keyword(s):  
Semantic Memory ◽  
Conceptual Knowledge ◽  
Procedural Knowledge ◽  
Dual Process ◽  
Long Term Memory ◽  
Cognitive Ethology ◽  
System 2 ◽  
System 1 ◽  
Level Of Analysis

A recent naturalistic epistemological account suggests that there are three nested basic forms of knowledge: procedural knowledge-how, conceptual knowledge-what, and propositional knowledge-that. These three knowledge-forms are grounded in cognitive neuroscience and are mapped to procedural, semantic, and episodic long-term memory respectively. This article investigates and integrates the neuroscientifically grounded account with knowledge-accounts from cognitive ethology and cognitive psychology. It is found that procedural and semantic memory, on a neuroscientific level of analysis, matches an ethological reliabilist account. This formation also matches System 1 from dual process theory on a psychological level, whereas the addition of episodic memory, on the neuroscientific level of analysis, can account for System 2 on the psychological level. It is furthermore argued that semantic memory (conceptual knowledge-what) and the cognitive ability of categorization are linked to each other, and that they can be fruitfully modeled within a conceptual spaces framework.

scholarly journals The psychology of diagnostic error

2015 ◽  
Vol 8 (3) ◽  
pp. 91-98
Author(s):  
L. Zwaan
Keyword(s):  
Diagnostic Errors ◽  
Diagnostic Error ◽  
Dual Process ◽  
Dual Process Theory ◽  
Process Theory ◽  
Diagnostic Process ◽  
Cognitive Errors ◽  
System 2 ◽  
System 1 ◽  
Analytic Reasoning

Diagnostic errors in medicine occur frequently and the consequences for the patient can be severe. Cognitive errors as well as system related errors contribute to the occurrence of diagnostic error, but it is generally accepted that cognitive errors are the main contributor. The diagnostic reasoning process in medicine, is an understudied area of research. One reason is because of the complexity of the diagnostic process and therefore the difficulty to measure diagnostic errors and the causes of diagnostic error. In this paper, I discuss some of the complexities of the diagnostic process. I describe the dual-process theory, which defines two reasoning modes, 1. a fast, automatic and unconscious reasoning mode called system 1, and a slow and analytic reasoning mode called system 2. Furthermore, the main cognitive causes of diagnostic error are described.

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