Mechanical behavior of aluminum honeycomb sandwich structures under extreme low temperature conditions

Abstract The current study is an effort to characterize the mechanical response of panels that are used as structural elements at low temperature applications. For the above reason, plaques of aluminum honeycomb sandwich were exposed for a certain period of time at different low temperature profiles ranging from 23°C to -70°C so that possible variation of their mechanical properties due to temperature exposure to be justified. Four different temperatures namely 23°C, 0°C, -40°C and -70°C were applied to these plaques prior mechanical testing that was performed at different loading modes. Specimens were obtained from these plaques in order to study the effect of low temperature on mechanical behavior and damage response of the specific sandwich structures. Extensive mechanical testing was carried out by means of tensile, compression and bending loading and the respective mechanical properties occurring from these tests were determined. From the results occurring from experimental data obtained from mechanical testing it is evident that there is a moderate decrease of ultimate strength and yield strength of the material as service temperature decreases in tensile, edgewise and flatwise compression as well as in three point bending loading modes. Moreover a drop in temperature results in a decrease in strain at rupture at tensile and compression loading.</jats:p

Mechanical behavior of aluminum honeycomb sandwich structures under extreme low temperature conditions

The current study is an effort to characterize the mechanical response of panels that are used as structural elements at low temperature applications. For the above reason, plaques of aluminum honeycomb sandwich were exposed for a certain period of time at different low temperature profiles ranging from 23×C to -70×C so that possible variation of their mechanical properties due to temperature exposure to be justified. Four different temperatures namely 23×C, 0×C, -40×C and -70×C were applied to these plaques prior mechanical testing that was performed at different loading modes. Specimens were obtained from these plaques in order to study the effect of low temperature on mechanical behavior and damage response of the specific sandwich structures. Extensive mechanical testing was carried out by means of tensile, compression and bending loading and the respective mechanical properties occurring from these tests were determined. From the results occurring from experimental data obtained from mechanical testing it is evident that there is a moderate decrease of ultimate strength and yield strength of the material as service temperature decreases in tensile, edgewise and flatwise compression as well as in three point bending loading modes. Moreover a drop in temperature results in a decrease in strain at rupture at tensile and compression loading. © Published under licence by IOP Publishing Ltd

Mechanical response and strength characteristics of aluminum honeycomb sandwich panels for infrastructure engineering

Abstract The use of aluminium sandwich panels has been increased in a certain number of engineering applications from infrastructure systems and transportation to aircraft and naval engineering. Due to their structural efficiency these materials are ideal for applications where ratio of strength to weight is of crucial importance. In the current study the investigation of the strength characteristics of aluminium sandwich panels with aluminium honeycomb core and different types of skins is performed using both analytical models and experimental procedures. A series of strength tests such as tension, shear, three point bending and double cantilever beam were conducted on aluminium honeycomb-cored sandwich panel specimens with five different skins in order to examine the mode of failure and the mechanical behaviour of the structural elements. The experimental findings are compared to theoretical values while an attempt for the explanation of the mechanisms leading to failure such as buckling, delamination or debonding between core and skins is performed. The results occurring from the study are very useful for the enhancement of the mechanical behaviour of sandwich constructions, thus more intensive work must be carried out in order to understand the physical mechanisms leading to strength characteristics of sandwich panels.</jats:p

Closed-Form Solutions of Linear Ordinary Differential Equations with General Boundary Conditions

This paper deals with the solution of boundary value problems for ordinary differential equations with general boundary conditions. We obtain closed-form solutions in a symbolic form of problems with the general n-th order differential operator, as well as the composition of linear operators. The method is based on the theory of the extensions of linear operators in Banach spaces.</jats:p