Forgot your password?
New user?
New Window Opens on the Secret Life of Microbes: Scientists Develop First Microbial Profiles of Ecosystems
CAS announces the release of SciFinder Scholar for Mac OS X
Press Releases
Press Releases
| Check out our New Publishers' Select for Free Articles |
Applied Composite Materials: An International Journal for the Science and Application of Composite Materials (v.4, #1)
Temperature predictions in thick composite laminates at low cure temperatures by Kurt S. Olofsson (pp. 1-11).
Results from experiments and simulation of the cure behaviour of thick glass/epoxy laminates cured at low initial temperatures are presented. The objective is to study how sensitive the temperature development in a commercial epoxy is to initial cure temperature for a few different combinations of wall thickness and fiber content. The general accuracy of all the temperature predictions are good. For low initial cure temperatures (50–80°C), will however small inaccuracies in the reaction kinetics and material data have an effect on the predictions. Analysis of the results indicates that the main error source is likely to be the used reaction kinetics data/model at these temperatures. These inaccuracies will furthermore affect the temperature predictions during the remaining cure cycle.
Keywords: cure; reaction kinetics; thermal properties; glass/epoxy
Temperature Predictions in Thick Composite Laminates at Low Cure Temperatures by Kurt S. Olofsson (pp. 1-11).
Results from experiments and simulation of the cure behaviour of thick glass/epoxy laminates cured at low initial temperatures are presented. The objective is to study how sensitive the temperature development in a commercial epoxy is to initial cure temperature for a few different combinations of wall thickness and fiber content. The general accuracy of all the temperature predictions are good. For low initial cure temperatures (50–80circC), will however small inaccuracies in the reaction kinetics and material data have an effect on the predictions. Analysis of the results indicates that the main error source is likely to be the used reaction kinetics data/model at these temperatures. These inaccuracies will furthermore affect the temperature predictions during the remaining cure cycle.
Keywords: cure; reaction kinetics; thermal properties; glass/epoxy
Identification of the damping properties of orthotropic composite materials using a mixed numerical experimental method by J. De Visscher; H. Sol; W. P. De Wilde; J. Vantomme (pp. 13-33).
A mixed numerical experimental approach is the basis of a new method for the identification of the material damping properties of fibre reinforced polymers, which provides an answer to many problems encountered in experimental damping characterization. Experimental modal parameters, measured on a plate specimen, are compared with corresponding results from a numerical calculation, thus allowing to determine the stiffness and damping properties of the material. The relation between the modal parameters (structural parameters) and the material parameters, is obtained by using a numerical model of the specimen in combination with the modal strain energy method.In the first part of this paper, the complex moduli are introduced as measures for both material stiffness and damping and the relation between these complex moduli and the modal parameters of a thin plate specimen is derived. Next, the practical procedure of the mixed numerical experimental method is presented, followed by a procedure for estimating the reliability of the obtained results. Finally, two examples are discussed in which all the independent material damping properties are identified as functions of frequency.
Keywords: material characterization; complex moduli; vibrations; modal parameters; material damping
Identification of the Damping Properties of Orthotropic Composite Materials Using a Mixed Numerical Experimental Method by J. De Visscher; H. Sol; W. P. De Wilde; J. Vantomme (pp. 13-33).
A mixed numerical experimental approach is the basis of a new method for the identification of the material damping properties of fibre reinforced polymers, which provides an answer to many problems encountered in experimental damping characterization. Experimental modal parameters, measured on a plate specimen, are compared with corresponding results from a numerical calculation, thus allowing to determine the stiffness and damping properties of the material. The relation between the modal parameters (structural parameters) and the material parameters, is obtained by using a numerical model of the specimen in combination with the modal strain energy method.In the first part of this paper, the complex moduli are introduced as measures for both material stiffness and damping and the relation between these complex moduli and the modal parameters of a thin plate specimen is derived. Next, the practical procedure of the mixed numerical experimental method is presented, followed by a procedure for estimating the reliability of the obtained results. Finally, two examples are discussed in which all the independent material damping properties are identified as functions of frequency.
Keywords: material characterization; complex moduli; vibrations; modal parameters; material damping
Optimum Design of Erosion-Stable Heatshield Composite Materials by YU. I. Dimitrienko; G. A. Efremov; S. A. Chernyavsky (pp. 35-52).
The present paper describes the development of multilayered heatshield composite materials. These methods permit us to design an optimum composition of heatshield composite materials for aerospace equipment under different heat and mechanical influences.In accordance with the theory developed, an erosion-stable heatshield three-layered composite material was synthesized, consisting of the upper erosion-stable layer based on the fabric reinforcing filler, the middle high-temperature heatshield layer and the lower low-temperature heatshield layer. Thicknesses of the layers and compositions of the fillers are selected by the methods of optimum design. Specimens were manufactured and gas-dynamical testing was conducted on an erosion-stable composite revealing its very suitable properties and verifing the adequacy of the model developed for the optimum design of heatshield composites.
Keywords: erosion stability; multilayered heatshield composite material; optimum design
Optimum design of erosion-stable heatshield composite materials by Yu. I. Dimitrienko; G. A. Efremov; S. A. Chernyavsky (pp. 35-52).
The present paper describes the development of multilayered heatshield composite materials. These methods permit us to design an optimum composition of heatshield composite materials for aerospace equipment under different heat and mechanical influences.In accordance with the theory developed, an erosion-stable heatshield three-layered composite material was synthesized, consisting of the upper erosion-stable layer based on the fabric reinforcing filler, the middle high-temperature heatshield layer and the lower low-temperature heatshield layer. Thicknesses of the layers and compositions of the fillers are selected by the methods of optimum design. Specimens were manufactured and gas-dynamical testing was conducted on an erosion-stable composite revealing its very suitable properties and verifing the adequacy of the model developed for the optimum design of heatshield composites.
Keywords: erosion stability; multilayered heatshield composite material; optimum design
Pulsed Nd-YAG Laser Welding of A SiC Particulate Reinforced Aluminium Alloy Composite by T. M. Yue; J. H. Xu; H. C. Man (pp. 53-64).
This paper examines the laser welding behaviour of a SiC particulate reinforced Al-alloy 2124 composite using a pulsed Nd-YAG laser. The influences of laser welding parameters of laser intensity, pulse duration and the beam’s focus position on the depth of weld penetration as well as the size of fusion zone were investigated. These investigations have led to an optimum welding condition proposed for pulsed laser welding of SiC particulate reinforced aluminium alloy composites with minimum defects.
Keywords: pulsed laser welding; metal matrix composite; weld profile; threshold intensity; defects
Pulsed Nd-YAG laser welding of A SiC particulate reinforced aluminium alloy composite by T. M. Yue; J. H. Xu; H. C. Man (pp. 53-64).
This paper examines the laser welding behaviour of a SiC particulate reinforced Al-alloy 2124 composite using a pulsed Nd-YAG laser. The influences of laser welding parameters of laser intensity, pulse duration and the beam's focus position on the depth of weld penetration as well as the size of fusion zone were investigated. These investigations have led to an optimum welding condition proposed for pulsed laser welding of SiC particulate reinforced aluminium alloy composites with minimum defects.
Keywords: pulsed laser welding; metal matrix composite; weld profile; threshold intensity; defects