A New Lateral Extensometer

1941 ◽  
Vol 8 (4) ◽  
pp. A152-A154
Author(s):  
A. V. de Forest ◽  
A. R. Anderson
Keyword(s):  
Strain Gage ◽  
Electrical Resistance ◽  
Lateral Strain ◽  
Principal Stresses ◽  
The Individual

Abstract In this paper is described a new lateral-strain gage which utilizes the principle of change of electrical resistance in wires with strain. An application of the instrument to the field of photoelasticity is given in which the problem of determining the individual principal stresses in a model can be solved directly when the information given by the isochromatic pattern is combined with the sum of the principal stresses at the points in question, as determined by the new gage.

scholarly journals Modelling of Dual-Junction Solar Cells including Tunnel Junction

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Abdelaziz Amine ◽  
Yamina Mir ◽  
Mimoun Zazoui
Keyword(s):  
Solar Cells ◽  
Electrical Resistance ◽  
High Efficiency ◽  
Equivalent Circuit Model ◽  
Tunnel Diodes ◽  
Space Applications ◽  
Output Performance ◽  
Photovoltaic Energy Conversion ◽  
Current Voltage ◽  
The Individual

Monolithically stacked multijunction solar cells based on III–V semiconductors materials are the state-of-art of approach for high efficiency photovoltaic energy conversion, in particular for space applications. The individual subcells of the multi-junction structure are interconnected via tunnel diodes which must be optically transparent and connect the component cells with a minimum electrical resistance. The quality of these diodes determines the output performance of the solar cell. The purpose of this work is to contribute to the investigation of the tunnel electrical resistance of such a multi-junction cell through the analysis of the current-voltage (J-V) characteristics under illumination. Our approach is based on an equivalent circuit model of a diode for each subcell. We examine the effect of tunnel resistance on the performance of a multi-junction cell using minimization of the least squares technique.

scholarly journals Psychophysiological basis of individual human behavioral reactions

2021 ◽  
pp. 14-19
Author(s):  
Liliia Yukhymenko ◽  
Olena Pustovit
Keyword(s):  
Nervous System ◽  
Personality Traits ◽  
Interpersonal Relationships ◽  
Electrical Resistance ◽  
Personal Responsibility ◽  
Functional Mobility ◽  
Professional Activity ◽  
Maximum Speed ◽  
Autonomic Reactivity ◽  
The Individual

The aim of the research: elucidation of autonomic dynamics (according to the electrical resistance of the skin) during functional load, taking into account the individual-typological properties of the nervous system and psychological qualities of the individual. Materials and methods. Determined the functional mobility of nervous processes (FMNP, the method of M. V. Makarenko), electrical resistance of the skin (polygraph study), psychological personality traits (16-factor personality questionnaire by Cattell). Results. The relationship between FMNP, individual parameters of skin galvanic response and some personality traits has been identified. The questions concerning the role of individual-typological properties of the nervous system in the development of autonomic reactivity, their connection with psychological personality traits, prediction of possible behavioural reactions and states are considered. Conclusions. It was found that individuals with high FMNP in terms of sensorimotor response, more likely to have a variant of behavioral response, which is characterized by maximum speed and accuracy of the task, low anxiety. However, there is a risk of overstrain of the autonomic nervous system (according to the indicators of the phase electrical resistance of the skin (ERS)). In the case of low levels of FMNP, a variant of behavioural response with relatively low task efficiency, slow autonomic regulatory processes and a tendency to experience is more common. We claim that FMNP is involved in creating a neurodynamic, autonomic and psychological basis for individual behaviour during sensorimotor response in emotionally stressful conditions. The identified differences can be useful for determining the optimal area of ​​professional activity, settling interpersonal relationships in the team, predicting the limits of acceptable actions and human actions, assessing the likelihood of risks of personal responsibility, the degree of stress, and so on

An Application of the Interferometer Strain Gage in Photoelasticity

1935 ◽  
Vol 2 (3) ◽  
pp. A99-A102
Author(s):  
R. W. Vose
Keyword(s):  
Strain Gage ◽  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
Massachusetts Institute ◽  
Massachusetts Institute Of Technology ◽  
Lateral Deformation ◽  
Principal Stresses ◽  
Photoelastic Analysis ◽  
The Difference ◽  
Institute Of Technology

Abstract This paper was written at the suggestion of Mr. Mieth Maeser, in response to numerous inquiries concerning the methods of photoelastic analysis in use at the Massachusetts Institute of Technology. By the use of any of the usual photoelastic methods the difference of the principal stresses and their direction at any point in a suitable loaded specimen are determined, and through a knowledge of Poisson’s ratio their sum is obtained (and a solution made possible) by a measurement of the lateral deformation of the specimen by means of an interferometer strain gage. This instrument, together with its accessories and their use, is illustrated and described in the paper. Examples of the problems solved by the use of the instrument show its accuracy and the consistency of the results obtained by the method.

scholarly journals DEVELOPMENT OF A GENERAL SENSOR SYSTEM MODEL TO DESCRIBE THE FUNCTIONALITY AND THE UNCERTAINTY OF SENSING MACHINE ELEMENTS

2021 ◽  
Vol 1 ◽  
pp. 1243-1252
Author(s):  
Maximilian Hausmann ◽  
Peter Welzbacher ◽  
Eckhard Kirchner
Keyword(s):  
Strain Gauge ◽  
Electrical Resistance ◽  
Sensor Integration ◽  
System Model ◽  
Sensor System ◽  
Measurement Results ◽  
Machine Elements ◽  
The Individual ◽  
Quantities Of Interest

AbstractSensor integration as close to the process as possible provides advantages in the quality of the measurement results as well as the possibility to implement completely new sensor principles and to measure novel quantities of interest. Sensor integration at positions close to the process can be made possible, for example, through the development and application of Sensing Machine Elements (SME). In the first part of this contribution, a general sensor system model is proposed. It is based on the concept of measuring chains and allows the uniform description of functions and uncertainties within a conventional sensor or SME application. For this purpose, essential quantities are defined, which are required for a uniform understanding. In the second part, the presented sensor system model is applied to a load measuring strain gauge on a drive shaft. This enables the condition monitoring of the shaft and drive train by measuring the electrical resistance of the strain gauge and thus allowing conclusions about the acting drive torque. The individual functions and uncertainties of the strain gauge integration are presented in the system model. This example shows the applicability of the presented system model for sensors and SME.

scholarly journals A Finite Element Approach to the Behavior of the ITZ

2015 ◽  
Vol 764-765 ◽  
pp. 3-7
Author(s):  
Aylie Han ◽  
Sri Tudjono
Keyword(s):  
Finite Element ◽  
Cement Paste ◽  
Weak Link ◽  
Element Model ◽  
Material Behavior ◽  
Crystal Formation ◽  
Principal Stresses ◽  
Single Inclusion ◽  
Load Displacement ◽  
The Individual

The Interfacial Transition Zone (ITZ) between two basic materials having differentiations in their mechanical properties has always been intriguing. The stiffness disparities between the two will result in a very distinctive area, the interface. Cement based components such as mortar and concrete consist of the cement paste and aggregates, with the ITZ at the perimeter. When compared to the cement paste, this ITZ has a higher porosity with a dissimilar crystal formation. The resulting area therefore becomes the weak link in concrete. A Finite Element Model (FEM) was developed to construct the load-displacement behavior of a single inclusion specimen and to study the crack propagation within the ITZ. The ITZ was modeled as a linkage element having a double spring, perpendicular and parallel to the ITZ surface. The individual stiffness behavior of these springs was obtained from laboratory-tested specimens. Non-linearity was generated by evaluating the principal stresses and strains at Gauss points, while the CEB-FIB 2010 code was used for the constitutive material behavior of the mortar. Iteration is conducted by the arc-length method developed by Riks-Wempners. The load-displacement curves resulting from the FEM were validated with laboratory tested specimens to compare its effectiveness and assess the correctness of the model.

A Model for the Nonlinear Elastic Response of Large Arteries

1988 ◽  
Vol 110 (3) ◽  
pp. 185-189 ◽  
Author(s):  
D. Elad ◽  
A. Foux ◽  
Y. Kivity
Keyword(s):  
Strain Energy ◽  
Elastic Response ◽  
Lateral Strain ◽  
Principal Stresses ◽  
Incompressibility Condition ◽  
Large Arteries ◽  
Strain Energy Density Function ◽  
Empirical Relations ◽  
Infinitesimal Deformations ◽  
Nonlinear Elastic

The nonlinear elastic response of large arteries subjected to finite deformations due to action of biaxial principal stresses, is described by simple constitutive equations. Generalized measures of strain and stress are introduced to account for material nonlinearity. This also ensures the existence of a strain energy density function. The orthotropic elastic response is described via quasi-linear relations between strains and stresses. One nonlinear parameter which defines the measures of strain and stress, and three elastic moduli are assumed to be constants. The lateral strain parameters (equivalent to Poisson’s ratios in infinitesimal deformations) are deformation dependent. This dependence is defined by empirical relations developed via the incompressibility condition, and by the introduction of a fifth material parameter. The resulting constitutive model compares well with biaxial experimental data of canine carotid arteries.

Changes in Chemoreceptor Sensilla on the Maxillary Palps of Locusta Migratoria in Relation to Feeding

1972 ◽  
Vol 57 (3) ◽  
pp. 745-753 ◽  
Author(s):  
E. A. BERNAYS ◽  
W. M. BLANEY ◽  
R. F. CHAPMAN
Keyword(s):  
Food Deprivation ◽  
Small Proportion ◽  
Electrical Resistance ◽  
Locusta Migratoria ◽  
Chemical Stimulation ◽  
Steady Level ◽  
The Individual ◽  
Maxillary Palps

1. The electrical resistance across the tips of the maxillary palps of Locusta migratoria is high immediately after a feed, but falls to a steady level in about 2 h after feeding. 2. Only a small proportion of the individual sensilla on the domes of the palps respond to chemical stimulation immediately after feeding, but this proportion increases with the period of food deprivation. 3. Gentle manipulation of the tips of non-responsive sensilla causes them to respond. 4. It is suggested that the terminal pores of the sensilla can open and close and that the resistance across the tips of the palps varies inversely with the number of open sensilla. 5. The possible significance of the changes is discussed.

A PHOTOELASTIC ANALYSIS OF STRESS WAVE PROPAGATION IN A LAYERED MODEL

Geophysics ◽  
1966 ◽  
Vol 31 (5) ◽  
pp. 881-899 ◽  
Author(s):  
W. F. Riley ◽  
J. W. Dally
Keyword(s):  
Wave Propagation ◽  
Dynamic State ◽  
Lead Azide ◽  
Stress Wave Propagation ◽  
Principal Stresses ◽  
Individual Values ◽  
Isochromatic Fringe ◽  
Fringe Patterns ◽  
The Individual ◽  
Explosive Detonation

Dynamic photoelasticity was used to study some fundamental aspects of wave propagation in layered media and to obtain information on the dynamic state of stress associated with the various waves generated by a point source explosion. Columbia Resin CR‐39 and aluminum were used to obtain a model with an acoustical impedance‐mismatch between layers of 6 to 1. A Cranz‐Schardin multiple spark camera, operating at approximately 200,000 frames per second, was used to record the dynamic isochromatic fringe patterns associated with the propagating stress waves. Small charges of lead azide were used to explosively load the models. Six different wave types were clearly identified. In the region near the explosive detonation, the predominant waves were the incident [Formula: see text] wave and the reflected [Formula: see text] waves from the interface and the free boundary. In regions away from the explosive detonation the headwaves ([Formula: see text], [Formula: see text], and [Formula: see text]) dominate since their rate of attenuation is much lower than the rate associated with the incident dilatational or the reflected shear waves. The data obtained in the form of isochromatic fringe patterns were converted to individual values of the principal stresses in several instances. The methods developed for this separation are applicable whenever the dilatational or distortional waves occur alone. The separation method requires no auxiliary data other than the isochromatic fringe orders and yields dynamic displacement data in addition to the individual values of the principal stresses.

Structural Efficiency of a Natural Composite

1992 ◽  
Vol 278 ◽  
Author(s):  
Joseph E. Saliba ◽  
Georges E. Sawaya
Keyword(s):  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Pure Bending ◽  
Bending Properties ◽  
Principal Stresses ◽  
Fiber Volume ◽  
Structural Efficiency ◽  
The Individual ◽  
Natural Composite ◽  
Ply Orientation

AbstractThis study was initiated to investigate the structural efficiency of the “bessbeetle” (Odontotaenius Disjunctus) as compared to typical “man-made” or synthetic composites. This synthetic laminate is configured according to standard composites design practices. In fact, an orthotropic unidirectional T300 tape with circular fibers and 60% fiber volume fraction is used. The specific ply orientation of the symmetric man-made composite is [0/+45/-45/90]2S. The natural laminate studied is unsymmetric with the individual plies made of the same orthotropic unidirectional T300 tape but with different ply orientation. Contrary to previous beliefs the natural composite did not assume a balance of inplane and bending properties which in essence mimic the behavior of isotropic behavior. The results of the efficiency of the natural composite for tension did not show any noticeable advantages while the pure bending case resulted in higher values for the principal stresses in the unsymmetric laminate.

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