Low Velocity Impact Properties of Foam Sandwich Composites – A Brief Review

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Low Velocity Impact Properties of Foam Sandwich Composites – A Brief Review
Volume 3, Issue 2, March 2014
Ramadan Mohmmed, Azzam Ahmed, Mohamed Ahmed Elgalib, Hashim Ali
College of Textiles Engineering, Key Laboratory of High Performance Fibers & Products, Ministry of
Education, Sudan University of Science and Technology, Khartoum , Sudan
Abstract — Composite sandwich structures have excellent properties and they are widely
used in the fields of high technology such as aeronautics and astronautics, etc.
Investigations of the mechanical properties of composite sandwich structures play a vital role in
deciding their applicability in various engineering fields. After years of effort, along with
several achievements, new difficulties have been encountered with the emergence of a lot of novel
sandwich structures in recent years. The quasi-static indentation response, low-velocity
impact response, residual strength after impact and high-velocity impact response of
these structures has been investigated by theoretical, numerical and experimental methods.
The mechanical behavior of sandwich structures is strongly dependent on the loading rate. In the
case of static loading the structure have a ductile behavior, but in the case of impact loading it
may behave in a brittle manner and fail catastrophically. The advances of the mechanical
properties of foam sandwich composites are reviewed from several aspects, including the,
low-velocity impact response, and the finite element model for low- velocity impact of composite sandwich structures.
Key words: carbon/epoxy laminates, foam sandwiched, composites finite element method, rohacell foam.
CONCLUSION AND FUTURE PROSPECTS
Sandwich structures are one of the most rapidly emerging classes in the construction of various composite
materials. Composite sandwich construction provided a unique opportunity to incorporate optical and other
materials for sensing, monitoring and advising regarding the ―health‖ of the structure during manufacture and use.
Impact tests are used to study dynamic deformation and failure modes of materials. Impact tests on composite
plates could be performed by using drop-weight machine and also by ABAQUS/Explicit. Different impact
energies, impact locations, peak loading and simulation of complicated damage problem and residual tensile
strengths could be predicted by this testing. Another testing which is being used to evaluate the structural features
of sandwich structures is the quasi-static testing.
It has been observed that cracks initiate from the tensile side and propagate to the compressive side within the core
in all sandwich structure specimens. Final failure only occurs when the bottom skin fails. The future for sandwich
construction looks bright indeed. Sandwich construction will continue to be the primary structure for satellites. In
aircraft, sandwich construction will be increasingly used particularly for large aircraft. Several countries are now
using composite sandwich constructions for their navy’s ship hulls. However one of the largest uses will be for
bridge constructions. Not only will it be used in those states whose departments of transportation (DOT) are or
become knowledgeable, but there is a large international market in developing countries who may welcome the
advantages. Finally, with the growing need for alternative sources of energy, wind energy mill systems are being
developed all of which rely heavily on composite sandwich constructions.
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