Developments in sandwich construction

Tajbakhsh, S

Abstract

The research is divided into two parts. In the first
part the structural behaviour of sandwich beams using
timber-based facings and foamed plastic cores was
studied. Various available theories were examined and
the most appropriate theory for this type of panel was
identified. In an extensive test programme the relevant
properties of the constituent materials were measured
and the data used in the proposed theory of structural
behaviour to predict beam deflections and core and
facing stresses. Corresponding sandwich beam tests were
carried out on the range of skin/core combinations and
the theoretical and experimental behaviours were
compared. Good agreement was confirmed within the range
of span/depth ratios investigated, confirming the
applicability of the theory for semi-thick timber-based
facings. A variety of timber based facings were
investigated and those most suitable for sandwich
construction were identified.
This type of panel construction has many advantages but
lacks the benefit of good fire resistance. The recF.iired
fire resistance could be provided by a suitable core
material.
Part two of the research concentrated on the development
of a new core material which was intended to have good
structural properties at reasonable density, and to have
adequate fire resistance free from the production of smoke and toxic fumes. Coated paper honeycombs were
chosen for the study. The properties of the constituent
materials were investigated in detail and then the
structural properties of the developed cores were
measured using methods drawn from national and
international standards. One particular coating
combination proved to be effective in terms of
stiffness, fire resistance, freedom from micro cracking
and strength retention at high temperature. This was
based on a mixture of sodium silicate and ball clay.
Cores were tested both with cells empty (to be blocked
by intumescence) and with cells filled (e.g. with
lightweight filler). In the best of the developed cores,
shear stiffness and transverse stiffness were much
higher than in normal core materials. On the basis of
the test programme, panels can be designed to give a
fire resistance defined by insulation of up to two hours.

Citation

Tajbakhsh, S. Developments in sandwich construction. (Thesis). University of Salford

• Thesis Type: Thesis
• Deposit Date: Aug 17, 2011
• Publicly Available Date: Aug 17, 2011
• Award Date: Jan 1, 1992