A New Polycarbonate and Glass Laminate and Its Affects on the Relationship Between Residual Tensile Stresses and Impact Resistance of Windshields

2002 ◽  
Author(s):  
David A. Danaher ◽  
Wendy S. Johnson ◽  
Ben T. Railsback ◽  
Richard M. Ziernicki
Keyword(s):  
Impact Resistance ◽  
Glass Laminate ◽  
Tensile Stresses ◽  
The Relationship

Relationship between physical and mechanical properties of accelerated weathering and outdoor weathering of PVC-coated membrane material under tensile stress

2016 ◽  
Vol 47 (2) ◽  
pp. 197-210 ◽  
Author(s):  
Xudong Yang ◽  
Xiuting Jiang ◽  
Jiyong Hu ◽  
Fangjuan Wang ◽  
Chun Hu
Keyword(s):  
Tensile Strength ◽  
Physical And Mechanical Properties ◽  
Accelerated Weathering ◽  
Membrane Material ◽  
Whiteness Index ◽  
Carbonyl Index ◽  
Tensile Stresses ◽  
The Relationship ◽  
Coated Membrane ◽  
Outdoor Weathering

To estimate the photo-oxidation aging performance of PVC-coated membrane material in atmospheric conditions under tensile stresses, the relationship between physical and mechanical properties under accelerated weathering test and outdoor weathering test is studied with the same cumulative UV radiation energy. And then, both tensile strength and whiteness index were measured and compared to characterize the property change of membrane material after aging under four different tensile stresses (0%, 5%, 10% and 20% of the breaking strength), respectively. In addition, FTIR spectrometry was applied to characterize the chemical components of the samples under different weathering conditions, and the carbonyl index was extracted. The results show that there were significant differences of tensile strength and carbonyl index between two kinds of aging conditions, whereas with the increasing tensile stresses, the whiteness index represented a consistent increasing deviation of accelerated weathering from the outdoor weathering. However, the relationship have been built between both whiteness index and tensile strength retention of accelerated weathering and those of outdoor weathering conditions after a Schwarzschild’s modification. Therefore, the service lifespan of PVC-coated membrane materials can be evaluated by accelerated weathering tests under tensile stresses.

scholarly journals Morphological and Tribological Properties of PMMA/Halloysite Nanocomposites

Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 816 ◽  
Author(s):  
Zina Vuluga ◽  
Mihai Corobea ◽  
Cristina Elizetxea ◽  
Mario Ordonez ◽  
Marius Ghiurea ◽  
...  
Keyword(s):  
Interfacial Adhesion ◽  
Phase Distribution ◽  
Impact Resistance ◽  
Cost Effective ◽  
Halloysite Nanotubes ◽  
Scratch Resistance ◽  
Polymer Processing ◽  
Interfacial Compatibility ◽  
The Relationship ◽  
Dispersion Of Nanoparticles

From an environmental and cost-effective perspective, a number of research challenges can be found for electronics, household, but especially in the automotive polymer parts industry. Reducing synthesis steps, parts coating and painting, or other solvent-assisted processes, have been identified as major constrains for the existing technologies. Therefore, simple polymer processing routes (mixing, extrusion, injection moulding) were used for obtaining PMMA/HNT nanocomposites. By these techniques, an automotive-grade polymethylmethacrylate (PMMA) was modified with halloysite nanotubes (HNT) and an eco-friendly additive N,N′-ethylenebis(stearamide) (EBS) to improve nanomechanical properties involved in scratch resistance, mechanical properties (balance between tensile strength and impact resistance) without diminishing other properties. The relationship between morphological/structural (XRD, TEM, FTIR) and tribological (friction) properties of PMMA nanocomposites were investigated. A synergistic effect was found between HNT and EBS in the PMMA matrix. The synergy was attained by the phase distribution resulted from the selective interaction between partners and favourable processing conditions. Modification of HNT with EBS improved the dispersion of nanoparticles in the polymer matrix by increasing their interfacial compatibility through hydrogen bonding established by amide groups with aluminol groups. The increased interfacial adhesion further improved the nanocomposite scratch resistance. The PMMA/HNT-EBS nanocomposite had a lower coefficient of friction and lower scratch penetration depth than PMMA/HNT nanocomposite.

The Koyna earthquake and the damage to Koyna Dam

1973 ◽  
Vol 63 (2) ◽  
pp. 381-397
Author(s):  
Anil K. Chopra ◽  
P. Chakrabarti
Keyword(s):  
Strong Ground Motion ◽  
The Finite Element Method ◽  
Dynamic Effects ◽  
Gravity Dams ◽  
Surface Wave Magnitude ◽  
Tensile Stresses ◽  
Present Design ◽  
The Relationship ◽  
Strong Ground ◽  
Made In

abstract The Koyna earthquake (surface-wave magnitude 6.5) occurred on December 11, 1967 near Koyna Dam in a region of India which was considered to be stable and nearly nonseismic. The relationship between the recent increase in number of earthquake occurrences in the vicinity of Koyna Dam and the filling of the reservoir behind the dam is discussed. The response of the dam to the strong ground motion recorded during the Koyna earthquake is analyzed by the finite element method including dynamic effects of the reservoir. The cracking anticipated in the monoliths of Koyna Dam on the basis of stresses obtained from these analyses and strength of concrete in the dam is consistent with the earthquake damage. On the basis of analytical results, it would be useful to provide relatively higher strength concrete in selected parts of gravity dams; appropriate suggestions are made in this connection. Present design criteria need to be improved to recognize that significant tensile stresses occur in gravity dams during earthquakes and to provide for the consequences of these tensile stresses.

Current Developments in the Area of Micromilling Tools: Diamond Deposition and Wear Characteristics

2006 ◽  
Author(s):  
M. J. Jackson ◽  
G. M. Robinson ◽  
W. Ahmed
Keyword(s):  
Crystallite Size ◽  
Chemical Vapor ◽  
Industrial Applications ◽  
Tensile Stresses ◽  
Machining Forces ◽  
Maximum Value ◽  
Chemical Vapor Deposited ◽  
Diamond Grain ◽  
The Relationship ◽  
Milling Tools

Chemical vapor deposited diamond films have many industrial applications but are assuming increasing importance in the area of micro engineering, most notably in the development of diamond coated micromilling tools. For these applications the control of structure and morphology is of critical importance. The crystallite size, orientation, surface roughness, and the degree of sp3 character have a profound effect on the tribological properties of the films deposited. In this paper we present experimental results on the effects of nitrogen doping on the surface morphology, crystallite size, and wear of micromilling tools. The sp3 character optimises at 200 ppm of nitrogen and above this value the surface becomes much smoother and crystal sizes decrease considerably. Fracture induced wear of the diamond grain is the most important mechanism of material removal from a micromilling tool during the grinding process. Fracture occurs as a consequence of tensile stresses induced into diamond grains by grinding forces to which they are subjected. The relationship between the wear of diamond coated milling tools, component machining forces, and induced stresses in the model diamond grains is described in detail. A significant correlation is found between the maximum value of tensile stress induced in the diamond grain and the appropriate wear parameter, in this case the grinding ratio. It is concluded that the magnitude of tensile stresses induced in the diamond grain by machining forces at the rake face is the best indicator of tool wear during the micromachining process.

scholarly journals Mathematical Model for Charpy Impact Energy of V-Notch Specimens

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Wei Wang ◽  
Ping Wang ◽  
Xuesong Liu ◽  
Zhibo Dong ◽  
Hongyuan Fang
Keyword(s):  
Mathematical Model ◽  
Impact Energy ◽  
Material Properties ◽  
Theoretical Basis ◽  
Impact Resistance ◽  
Charpy Impact ◽  
The Impact ◽  
The Mathematical Model ◽  
The Relationship ◽  
Derivation Process

Firstly, by analyzing the response of Charpy V-notch specimen impacted by pendulum, the relationship between specimen geometry, material properties, and impact energy is established and simplified, and the mathematical model for evaluating impact energy of specimens with different sizes is established. Then, the effectiveness of the model through a series of impact tests is verified. Theoretical analysis and experimental results show that the relationship between ligament length and impact energy is quadratic, while the relationship between ligament thickness and impact energy is linear. In the derivation process, the intrinsic impact toughness is used to evaluate the toughness of materials. The mathematical model makes it possible to evaluate the impact energy of specimens with different sizes and provides a theoretical basis for evaluating the impact resistance of structures.

INFLUENCE OF EXTERNAL FORCE FACTORS ON THE STRENGTH OF UNIFORMLY LOADED CONSOLE-FIXED PARTS SUBJECT TO ABRASIVE WEAR

2021 ◽  
pp. 41-45
Author(s):  
ALEKSANDR M. MIKHALCHENKOV ◽  
Keyword(s):  
Abrasive Wear ◽  
External Force ◽  
Theoretical Study ◽  
Mathematical Expression ◽  
Uniform Loading ◽  
Pinch Point ◽  
Tensile Stresses ◽  
Mathematical Relationships ◽  
The Relationship ◽  
Metal Polymer

The intensity of wear observed in the working parts of machines operating in an abrasive environment largely determines their service life. However, in a number of cases, the downtime of equipment is associated with fractures of the operating elements casued by their abrasion. In this case, the operational state of the product is determined by the tolerable stresses. Theoretical studies on fi nding the mathematical relationships connecting wear and tolerable stresses are thus relevant. In addition, they are general and can be applied to various materials: metal, polymer, and composite ones. The goal of the present research is to make a theoretical study of the infl uence of external force factors on the strength of cantilever-fi xed parts of various geometric shapes in the process of their abrasive wear during the period of operation under uniform loading. In other words, the authors seek to determine the theoretical value of the limiting wear of a part according to the tolerable stresses. As a result of the study, a mathematical expression was obtained to establish the relationship between the maximum tolarable stresses and the value of the limiting wear of a cantilever-fi xed part under uniform loading. This relationship is necessary to analyse the values of the maximum tensile stresses in its sections. It has been established that the maximum tensile stresses are characteristic of the pinch point of the beam, regardless of its shape.

Microstructure and Mechanical Properties of Functionally Graded Cemented Carbides of Coarse Grain Prepared by Solid Carburizing

2018 ◽  
Vol 777 ◽  
pp. 350-355
Author(s):  
Bin Liu ◽  
Mei Mei Zhang ◽  
Ying Hao Feng ◽  
Xiao Feng Li
Keyword(s):  
Mechanical Properties ◽  
Impact Resistance ◽  
High Strength ◽  
Functionally Graded ◽  
Cemented Carbide ◽  
Coarse Grain ◽  
Functional Gradient ◽  
Gradient Layer ◽  
The Relationship ◽  
Carburizing Process

The cemented carbide with coarse grain is widely used in mining drilling due to high thermal conductivity, high strength and impact resistance and so on. Functionally graded cemented carbide with coarse grain were prepared by solid carburizing in this research. The different carburizing process was studied, and the relationship between carburizing process and the microstructure, mechanical properties were studied. The carburizing efficiency was lower and the formation the gradient layer was slowly for coarse grain cemented carbide at different carburizing temperatures. When the carburizing temperature was lower than 1440 °C, it was difficult to prepare the functional gradient cemented carbide. While higher than 1450 °C, functional gradient cemented carbide can be formed by solid carburizing. The thickness of gradient layer was close among carburizing temperature from 1450 °C to 1490 °C. However, the carburizing time had the more significant effect on the carburizing reaction the formation of the gradient layer.

Impact Resistance of Automobile Tires

1968 ◽  
Vol 41 (4) ◽  
pp. 1051-1064
Author(s):  
E. W. Lothrop
Keyword(s):  
Kinetic Energy ◽  
High Speed ◽  
Impact Resistance ◽  
Test Machine ◽  
Test Results ◽  
Laboratory Test Results ◽  
Breaking Energy ◽  
The Impact ◽  
The Relationship ◽  
Automobile Tires

Abstract The construction and operation of a high speed plunger test machine to determine the impact energy required to produce failure of automobile tires are described. The equipment has been designed to operate over an energy range of 1500 to 15,000 in. lb at preselected velocities between 40 and 100 mph and at preselected temperatures between 75 and 300° F. These ranges are adequate to permit the testing of passenger tires over a range of conditions simulating those encountered in high speed driving. The test machine consists of a pneumatic gun for propelling the plunger at an inflated tire, mounted in a temperature controlled cabinet, and photoelectric devices for measuring plunger velocity. In a test the kinetic energy of the plunger is increased in increments, until failure occurs. The minimum kinetic energy required to cause failure of the tire fabric is taken as a measure of the carcass breaking energy. Data on rayon and nylon cord tires indicate that the breaking energy of a tire is dependent on both speed and temperature and that the relationship between energy, speed, and temperature depends on the cord-reinforcing material in the tire. As a result it is impossible to predict the relative impact resistance of tires under use conditions on the basis of laboratory test results obtained with the standard static plunger test, in which the plunger penetrates the tire at 2 in./min at room temperature.

Application of thermography method to the investigation of two-dimensional elastic-plastic states

2012 ◽  
Vol 59 (3) ◽  
pp. 297-312
Author(s):  
Barbara Kozłowska
Keyword(s):  
Temperature Distribution ◽  
Experimental Testing ◽  
Two Dimensional ◽  
Stress Concentrators ◽  
Tensile Stresses ◽  
Elastic Plastic ◽  
Loading Process ◽  
Temperature Increment ◽  
Plastic Zones ◽  
The Relationship

In the paper, the author presents the application of thermography method for investigation of elastic-plastic states in two-dimensional models. The experimental testing was carried out on the duralumin elements with different stress concentrators loaded by uniformly distributed tensile stresses. The changes of temperature distribution on the surface of the models during loading process were recorded by a thermovision camera. On the basis of calibrating test carried out on the stretched element, the relationship between loading, temperature increment and specimen elongation was determined. Quantitative temperature distribution in chosen crosssections of the models was determined using thermograms received for various levels of loading. On the basis of the obtained results, the author estimated the accuracy of the method as well as its usability for investigation of the plastic zones’ localization and propagation.

Interstellar gas in the central region of the Galaxy

1967 ◽  
Vol 31 ◽  
pp. 239-251 ◽  
Author(s):  
F. J. Kerr
Keyword(s):  
Central Region ◽  
Galactic Plane ◽  
Neutral Hydrogen ◽  
Continuum Emission ◽  
Galactic Centre ◽  
Interstellar Gas ◽  
Hydrogen Recombination ◽  
The Galaxy ◽  
Centre Region ◽  
The Relationship

A review is given of information on the galactic-centre region obtained from recent observations of the 21-cm line from neutral hydrogen, the 18-cm group of OH lines, a hydrogen recombination line at 6 cm wavelength, and the continuum emission from ionized hydrogen.Both inward and outward motions are important in this region, in addition to rotation. Several types of observation indicate the presence of material in features inclined to the galactic plane. The relationship between the H and OH concentrations is not yet clear, but a rough picture of the central region can be proposed.

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