Thermally Induced Twist in Graphite-Epoxy Tubes

1988 ◽  
Vol 110 (2) ◽  
pp. 83-88 ◽  
Author(s):  
M. W. Hyer ◽  
C. Q. Rousseau ◽  
S. S. Tompkins
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Plane Deformation ◽  
Radial Position ◽  
Elasticity Analysis ◽  
Thermally Induced ◽  
Classical Lamination Theory ◽  
Experimental Apparatus ◽  
Lamination Theory

This paper discusses an analytical and experimental study to investigate the thermally induced twist in laminated angle-ply graphite-epoxy tubes. Attention is focused on balanced laminates which, contrary to intuition, exhibit twist when the temperature is changed. The twisting is due to the fact that in tube a lamina with a + Φ orientation and a lamina with a − Φ orientation must be at slightly different radial positions. The lamina with the greater radial position determines the sense of the twist. Classical lamination theory does not predict this phenomenon and so a more sophisticated theory must be employed. This paper outlines such a theory, which is based on a generalized plane deformation elasticity analysis, and presents experimental data to confirm the predictions of the theory. A brief description of the experimental apparatus and procedure used to measure twist is presented.

Analysis of the Non-Linear Behavior of ECLIPSE Actuators

Aerospace ◽  
2005 ◽  
Author(s):  
Kyle G. Webber ◽  
Christopher S. Lynch
Keyword(s):  
Residual Stress ◽  
Lead Zirconate Titanate ◽  
Epoxy Composite ◽  
Plane Deformation ◽  
Stress Gradient ◽  
Curing Temperature ◽  
Classical Lamination Theory ◽  
Linear Behavior ◽  
Non Linear ◽  
Lamination Theory

This work discusses the development and characterization of rectangular shaped Epoxy Composite Laminated Piezoelectric Stress-Enhanced actuators (ECLIPSE). ECLIPSE actuators are unimorph type d31 actuators that are manufactured with a lead zirconate titanate (PZT) plate sandwiched between unidirectional Kevlar 49/epoxy composite layers with dissimilar coefficients of thermal expansion in orthogonal directions. Cooling the actuator from an elevated curing temperature resulted in a residual stress gradient through the actuator, a compressive stress on the brittle piezoelectric plate, and a large out-of-plane deformation. Extended classical lamination theory (ECLT) is used to model the residual stress state and curvature of the actuator. The model results are compared to the classical lamination theory. The ECLT was developed by Hyer to explain the non-linear behavior of unsymmetric cross-ply laminates [1-3]. Three actuator layups were fabricated and characterized: [90/PZT/90/0], [90/90/PZT/90/0/0], and [90/90/90/PZT/90/0/0/0]. It is shown that geometric non-linearity is important to consider when modeling ECLIPSE actuators.

Calculations of the Room-Temperature Shapes of Unsymmetric Laminatestwo

1981 ◽  
Vol 15 (4) ◽  
pp. 296-310 ◽  
Author(s):  
Michael W. Hyer
Keyword(s):  
Experimental Data ◽  
Room Temperature ◽  
Quantitative Information ◽  
Total Potential Energy ◽  
Geometric Nonlinearities ◽  
Classical Lamination Theory ◽  
Unsymmetric Laminates ◽  
Total Potential ◽  
Lamination Theory ◽  
Saddle Shape

The cured shape of unsymmetric laminates do not always conform to the predictions of classical lamination theory. Classical lamination theory predicts the room-temperature shapes of all unsymmetric laminates to be a saddle. Experimental observations, however, indicate some unsymmetric laminates have cylindrical room-temperature shapes. In addition, some unsymmetric laminates exhibit two stable room-temperature configurations, both cylindircal. This paper presents a theory which explains these characteristics. The theory is based on an extension of classical lamination theory which accounts for geometric nonlinearities. A Rayleigh-Ritz approach to minimizing the total potential energy is used to obtain quantitative information regarding the room-temperature shapes of square T300/5208 [02/902] T and [04/904] T graphite-epoxy laminates. It is shown that, depending on the thickness of the laminate and the length of the side of the square, the saddle shape configuration is actually unstable. For values of length and thickness that render the saddle shape unstable, it is shown that two stable cylindrical shapes exist. The predictions of the theory are compared with existing experimental data.

EXPERIMENTAL STUDY OF THE KINEMATIC PARAMETERS OF MOVEMENT OF CARS FORCED IDLE MOTION

2018 ◽  
pp. 52-57
Author(s):  
Ivelin Kostov
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Experimental Research ◽  
Kinematic Parameters ◽  
Research Results ◽  
Software Product

In the work brought some experimental data of kinematic parameters of movement of cars forced idle, as the software product was used to diagnose 900 ATS, which recorded kinematic parameters of vehicle. On the basis of the conducted experimental research results are shown tabulated and analysed.

Modeling and Experimental Validation of the Effective Bulk Modulus of a Mixture of Hydraulic Oil and Air

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Hossein Gholizadeh ◽  
Doug Bitner ◽  
Richard Burton ◽  
Greg Schoenau
Keyword(s):  
Experimental Data ◽  
Bulk Modulus ◽  
Theoretical Models ◽  
Operating Conditions ◽  
Air Bubbles ◽  
Pressure Sensitivity ◽  
Hydraulic Oil ◽  
Effective Bulk Modulus ◽  
Experimental Apparatus ◽  
Major Factors

It is well known that the presence of entrained air bubbles in hydraulic oil can significantly reduce the effective bulk modulus of hydraulic oil. The effective bulk modulus of a mixture of oil and air as pressure changes is considerably different than when the oil and air are not mixed. Theoretical models have been proposed in the literature to simulate the pressure sensitivity of the effective bulk modulus of this mixture. However, limited amounts of experimental data are available to prove the validity of the models under various operating conditions. The major factors that affect pressure sensitivity of the effective bulk modulus of the mixture are the amount of air bubbles, their size and the distribution, and rate of compression of the mixture. An experimental apparatus was designed to investigate the effect of these variables on the effective bulk modulus of the mixture. The experimental results were compared with existing theoretical models, and it was found that the theoretical models only matched the experimental data under specific conditions. The purpose of this paper is to specify the conditions in which the current theoretical models can be used to represent the real behavior of the pressure sensitivity of the effective bulk modulus of the mixture. Additionally, a new theoretical model is proposed for situations where the current models fail to truly represent the experimental data.

Experimental study of hypochloremia

1935 ◽  
Vol 31 (8-9) ◽  
pp. 1112-1112
Keyword(s):  
Experimental Data ◽  
Experimental Study

Analyzing clinical and experimental data on hypochloremia, the authors show that both during vomiting and when giving diuretica, it is not only about the loss of chlorine, but at the same time a large amount of water is lost.

Kinetics of hypso anhydrites dissolution in water. Experimental studies

2019 ◽  
pp. 93-96
Author(s):  
A. L. Lebedev ◽  
I. V. Avilina
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Riccati Equation ◽  
Balance Equation ◽  
Experimental Studies ◽  
Common Ion ◽  
The Common ◽  
Common Ion Effect ◽  
Kinetics Of Dissolution ◽  
Kinetics Of

Experimental study of kinetics of dissolution of hypso anhydrites at 25 ᵒC made it possible to formulate model of the process in the form of a balance equation for the kinetics of dissolution of gypsum, anhydrite (first and second orders, respectively) and kinetics of precipitation of gypsum (second order). The processing of the experimental data were carried out on the basis of the solution of the Riccati equation. When taking into account the common-ion effect on the solubility of gypsum and anhydrite, the calculated values turned out to be more comparable with the experimental ones.

Effect of Tightening Speed on the Torque-Tension and Wear Pattern in Bolted Connections

2006 ◽  
Author(s):  
Sayed A. Nassar ◽  
Ramanathan M. Ranganathan ◽  
Saravanan Ganeshmurthy ◽  
Gary C. Barber
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Surface Roughness ◽  
Initial Level ◽  
Zinc Coating ◽  
Optical Microscope ◽  
Wear Pattern ◽  
Highly Sensitive ◽  
Contact Surfaces ◽  
Scanning Electron

This experimental study investigates the effect of tightening speed and coating on both the torque – tension relationship and wear pattern in threaded fastener applications. The fastener torque – tension relationship is highly sensitive to normal variations in the coefficients of friction between threads and between the turning head and the surface of the joint. Hence, the initial level of the joint clamp load and the overall integrity and reliability of a bolted assembly is significantly influenced by the friction coefficients. The effect of repeated tightening and loosening is also investigated using M12, Class 8.8, fasteners with and without zinc coating. The torque – tension relationship is examined in terms of the non-dimensional nut factor K. The wear pattern is examined by monitoring the changes in surface roughness using a WYKO optical profiler and by using a LECO optical microscope. A Hitachi S-3200N Scanning Electron Microscope (SEM) is used to examine the contact surfaces, under the fastener head, after each tightening/loosening cycle. Experimental data on the effect of variables and the tightening speed, fastener coating and repeated tightening on the nut factor are presented and analyzed for M8 and M12, class 8.8, fasteners.

Experimental Study of Typical Graded Asphalt Mixture about Dynamic Stability at High Temperature

2016 ◽  
Vol 858 ◽  
pp. 300-304
Author(s):  
Zhen Fu Chen ◽  
Dan Wu ◽  
Qiu Wang Tao ◽  
Yuan Chu Gan
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
High Temperature ◽  
Asphalt Mixture ◽  
Temperature Stability ◽  
Specimen Thickness ◽  
High Temperature Stability ◽  
Change Trend ◽  
Comparison And Analysis ◽  
The Stability

The high temperature stability of AC-16, AC-13, AC-20 under specimen thickness of 5cm and 6cm is studied through indoor asphalt mixture high rutting test, Through comparison and analysis about experimental data, it is found that the stability of AC-16, AC-13, AC-20 asphalt mixture at high- temperature decreases in turn. It is shown that thickness changes did not affect the change trend of the high temperature stability under gradation change, and the stability of AC-16 at high-temperature is the best, the AC-13 is second and the AC-20 is less.

Additive manufactured multi-material structure with directional specific mechanical properties based upon classical lamination theory

2018 ◽  
Vol 24 (7) ◽  
pp. 1212-1220 ◽  
Author(s):  
Sugavaneswaran M. ◽  
Arumaikkannu G.
Keyword(s):  
Mechanical Properties ◽  
Three Dimensional ◽  
Additive Manufacture ◽  
Material Structure ◽  
Loading Conditions ◽  
Content Type ◽  
Three Dimensional Printing ◽  
Classical Lamination Theory ◽  
Innovative Methodology ◽  
Lamination Theory

Purpose This paper aims to additive manufacture (AM) the multi-material (MM) structure with directional-specific mechanical properties based on the classical lamination theory of composite materials. Design/methodology/approach The polyjet three-dimensional printing (3DP) process is used to fabricate the MM structure with directional-specific mechanical properties. MMs within a layer are positioned and oriented based on the classical lamination theory to achieve directional-specific properties. Mechanical behavior of the AM structure was examined under various loading conditions to justify the directional-specific properties. Findings With MM processing capabilities of the polyjet 3DP machine, AM MM structures with directional-specific mechanical properties were fabricated. From experimentation, it was observed that the AM MM structure with a quasi-isotropic laminate has superior tensile and flexural strength, and the AM MM structure with an angle ply laminate has superior shear strength. Various mechanical properties determined through testing will be useful for the selection of an appropriate layup arrangement within a structure for appropriate loading conditions. Originality/value This study presents the innovative methodology for the fabrication of AM MM structures with tailor-made mechanical properties. The developed methodology paves way for using the polyjet 3DP MM structure for applications such as the complaint mechanism, snap fits and thin features, which require directional-specific properties.

An Experimental Study on the Lateral Impact of Fully Clamped Mild Steel Pipes

1992 ◽  
Vol 206 (2) ◽  
pp. 111-127 ◽  
Author(s):  
N Jones ◽  
S E Birch ◽  
R S Birch ◽  
L Zhu ◽  
M Brown
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Mild Steel ◽  
Failure Modes ◽  
Experimental Results ◽  
Lateral Impact ◽  
Drop Hammer ◽  
Steel Pipes ◽  
Scale Range ◽  
The Impact

This report presents some experimental data that were recorded from 130 impact tests on mild steel pipes in two drop hammer rigs. The pipes were fully clamped across a span which was ten times the corresponding outside pipe diameters which lie between 22 and 324 mm. All of the pipes except five had wall thicknesses of 2 mm approximately and were impacted laterally by a rigid wedge indenter at the mid span, one-quarter span or near to a support. The impact velocities ranged up to 14 m/s and caused various failure modes. Some comparisons between two sets of experimental results indicate that the laws of geometrically similar scaling are almost satisfied over a scale range of approximately five.

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