جستجوی مقالات مرتبط با کلیدواژه « لانه زنبوری » در نشریات گروه « مواد و متالورژی »

The needs of the human communities and industry to build low weight, high strength and durable structures have increased the demand for composite materials, including sandwich structures. In this case sandwich panels are used in situations requiring high mechanical strength, low weight, sound insulation and thermal insulation properties. In this study, carbon nanotubes-reinforced composite honeycomb sandwich panels, were constructed using silicone molding. To determine the role of carbon nanotubes on the compressive and bending behavior of sandwich panels, a different weight percentage of this material (0/025, 0/05. 0/075) was added to the epoxy resin. Also, different thicknesses (5mm, 2/5mm) were tested to determine the role of core wall thickness on the compressive and bending behavior of sandwich panels. The results showed that the compressive strength of honeycomb panels has a direct relation with the increase in the percentage of carbon nanotubes and also the thickness of the wall. The Compressive strength of Sandwich panels increased from 42/06 up to 54/32 MPa with increasing carbon from 0/025 up to 0/075 nanotubes. The compressive strength of sandwich panels with 5 mm honeycomb wall thickness and reinforced with 0/025, 0/05 and 0/075 weight percent of carbon nanotubes compared to sandwich panels with 2.5 mm honeycomb wall thickness were respectively 2/38, 2/15 and 2.17 times. also the flexural strength of 5-mm honeycomb wall thickness and reinforced with 025/0, 0/05 and 0.075% weight percent of carbon nanotubes compared to sandwich panels with 2.5 mm honeycomb wall thickness, were respectively 3, 2.66 and 2.7 times.

Sandwich structures are used in applications that required a combination of high rigidity and low weight same as aerospace, marine and automotive. Large and/or complicated sandwich structures are often manufactured by connecting pre-fabricated sandwich panels by means of connections, adhesive or bolts. In present study, two types of metallic connections were used to join two sandwich panels with glass-epoxy face-sheets and aluminum honeycomb core. Connections have the same material and different geometries and were bonded to the sandwich structures using the same epoxy as used to manufacture the face-sheets. Two groups of specimens were made and tested under bending loading. Also, a finite element simulation using LS-DYNA were performed to predict the behavior of sandwich structures. A good compliance between numerical and experimental results was observed. The effects of increasing the length and the thickness of the connections on the maximum force and energy absorption were investigated to examine the influences of involved parameters on bending response of a sandwich plates.

Analysis of porous structures, specifically honeycombs is of great importance; according to their two remarkable characteristics: excellent strength to weight ratio and noticeable energy absorption. In this survey, the experimental analysis of folding and densification of honeycombs subjected to blast loading is the main objective. To do so, ninety experiments were conducted on four different kinds of honeycombs. Afterwards, the results were compared to the analytical analysis of honeycombs under dynamic loading and also experimental analysis of honeycombs under quasi-static loading which have been reported by other researchers. A good agreement was observed between experimental results and analytical predictions. Moreover, comparing to static loading, the strength of honeycomb structures was improved under blast loading.