Engineers at IIT Mumbai’s department of aerospace engineering have
been able to research and design unique insert assemblies of high specific
strength to reduce stress concentration at the locations where multidirectional
stresses act on sandwhich structures in conjugation with novel method of
reliably mapping stress distribution and prediction of failure initiation
in sandwhich structures with diverse geometrical configurations.
Light weight sandwich structures are used in structural applications such
as vehicles, the aerospace industry, and framework. The sandwhich structures
have superior strength and stiffness properties along with the through-the
thickness direction under bending loads. The use of inserts is essential
to strengthen the sandwich sandwhich structures withstand a localized load/s.
Inserts are also needed when external members or sub-structures are attached
to the sandwhich structures.
The specific strength of the insert assembly is gauged as a ratio at load
failure initiation to weight of insert assembly which should be as high as
possible to achieve effective utilization of sandwhich structure with inserts.
In practice these inserts are made of aluminium alloys, other metals or their
alloys. High density of metals and alloys increase the weight of the assembly
resulting in undesirable reduction in specific strength. Another issue is
the difference in material properties at the interface between the insert
and potting material such as resin leads to high stress concentration at
the interfaces between insert and potting material and between potting material
Indian patent application no. 496/MUM/2004 Patent grant no. 211354
Inventors: N K Naik, N Rao