No abstract

No abstract

In recent years, material scientists have been focusing on the utilization of materials from natural resources due to environmental concerns. In the same context, the aim of this work is to evaluate impact response, sound absorption behavior, and vibration damping characteristics of natural-based composite sandwich made of flax as skin reinforcement and agglomerated cork as core. Vacuum bagging method was used for manufacturing composite sandwiches with different cork densities of 240, 280, and 340 kg/m3. Composite sandwiches have also been manufactured by using glass as skin reinforcement for comparison. Low velocity impact test was conducted and found that glass fiber reinforced composite sandwich required 73–77% more energy to perforate when compared to the flax fiber reinforced composite sandwich irrespective of core density. Flax fiber reinforced composite sandwich has 45–96% higher sound absorption capacity and 27–32% higher vibration damping ratio than glass fiber reinforced composite sandwich irrespective of core density. This is due to multiscale structure and cellular nature of the flax fiber and the cork materials, respectively. These enhancements in sound and vibration are accomplished with just little forfeits in perforation energy. This study recommends that, if optimized, the natural-based composite sandwich could be an ecologically appealing answer for automobile and construction applications, where impact behavior is important, along with sound and vibration properties.

The construction industry shows great interest in the use of technologically advanced materials which are light, environmentally friendly, possess high strength and durability for floors, roofs, partitions, etc. Apart from mechanical properties, the material should also possess excellent thermal and acoustic properties. In the same context, the aim of this study is to explore the flexuralstrength, thermal-conductivity, flame resistance, and sound-absorption capabilities of natural based material made with jute fiber and agglomerated cork. The natural based partition wall (jute board [JB]) was manufactured using vacuum bag molding process. Other alternative materials used in this study for comparison are gypsum and particle boards. A flexural test was carried out and it was observed that the JB has 80% of higher flexural strength than other test samples. It is also having lower thermal conductivity of 52.8% and 43.3% than gypsum and particle board, respectively. The JB have 35% and 10% higher sound absorption capabilities than gypsum and particle board, respectively. This is attributed to the multi-scale arrangement and cellular structure of jute fiber and cork material. This study recommends that, if flame resistance of jute fiber is enhanced with help of flame retardants, JB that is, jute/cork sandwich panel could be an environmentally appealing alternative answer for use in the construction of partition walls.

No abstract

The main objective of this paper is to study the effect of water absorption on the flexural strength of new green sandwich composite material made of flax as skin reinforcement and agglomerated cork as core. In this work, three different types of skin reinforcements and three different densities of agglomerated cork core have been used for the manufacturing of sandwich composites. The manufactured sandwich composites were subjected to three-point bending tests under both dry and wet conditions. The three-point bending results confirmed a decrease in the specific flexural strength by 14-42 % in wet samples due to water absorption. Also, the increase in core density leads to an increase in flexural strength both in dry and wet conditions. During testing under dry conditions, the specific flexural strength of flax reinforced sandwich composite was found to be superior because of the higher strength to weight ratio factor of flax fiber when compared to a glass reinforced sandwich composite and glass/flax reinforced hybrid sandwich composite. Due to the hydrophilic nature of flax fibers, flax reinforced sandwich composite has a reduced specific flexural strength in wet conditions when compared to glass reinforced sandwich composite and glass/flax reinforced hybrid sandwich composite.

Gearing is one of the most critical components in mechanical power transmission systems.. This paper explains about the comparison of the geometry of spur gears for two different modules by modeling and mathematical equations, load distribution at various positions of the contact line and the stress analysis of spur gears using three-dimensional finite element method. The bending stresses were examined using three-dimensional finite element model.. These stresses of different modules obtained from the finite element analysis were compared and the considerable reduction of weight occurred was found and also the values are compared with the theoretical values. Both results agree very well. This indicates that the finite element method model is accurate.

No abstract