OS-C501

Offshore Standard DNV-OS-C501, November 2013
Sec.5 Materials – sandwich structures – Page 77
1.5.4 It is possible that a structure is loaded in such a way that some material properties are not relevant. In
that case the non-relevant properties do not have to be known, but it shall be documented that the properties
are not relevant for the application.
1.5.5 If cores of the same type are used in different layers in the component, one test series is sufficient to
determine their properties.
1.5.6 Properties can be established as new, see App.D, or checked against typical values. The procedure is
given in Sec.4 [8.6].
1.5.7 Mechanical properties depend on the load conditions and the environment. Parameters related to the
topics should be accounted for, see this section headings [3], [4] and [5].
1.5.8 For test data, the load conditions and the environment parameters should be reported.
1.6 Characteristic values of mechanical properties
1.6.1 See Sec.4 [1.6].
2 Static properties
2.1 General
2.1.1 All material properties shall be given with full traceability of materials and conditions. Test results are
only valid if the information given in Table 5-1 and Table 5-2 is be available. Tests shall be reported as mean,
standard deviation, and number of tests.
2.1.2 For many applications the static properties after exposure to long term loads and environments are more
important than the static properties of a new material. This fact should be kept in mind when selecting materials
and developing a test programme. Long term properties are described in the following sections.
2.2 Static properties
2.2.1 The complete list of orthotropic data for core and adhesive materials is shown in the following tables.
Recommendations for test methods to obtain the properties are given in App.D.
2.2.2 Laminate faces elastic constants, strains, strengths and other mechanical properties are described in
Sec.4.
2.2.3 When different adhesives are used to bond faces and core together, or core layers together, a distinction
shall be made between adhesive(s) and matrix properties. In some cases, matrix and adhesive materials
properties are significantly dissimilar.
2.2.4 Static properties are assumed to be identical to quasi-static properties. Accordingly, strain rate should not
exceed a value of about 1% per minute.
2.2.5 The yield point for ductile core materials is defined as the 2% offset point.
2.2.6 The orthotropic static data for core materials are the following (note that other co-ordinate systems may
be chosen to describe the orthotropic behaviour, e.g. cylindrical co-ordinates):
Table 5-3 Mechanical static properties for core materials
Mechanical parameter Unit Reference in Appendix D
for measurement method
In-plane orthotropic elastic constants
E xt core linear Tensile modulus of elasticity of core in x-direction in [GPa] [D.2.1]
the linear range
E xc core linear Compressive modulus of elasticity of core in x- [GPa] [D.2.2]
direction in the linear range
E yt core linear Tensile modulus of elasticity of core transverse to y-
direction in the linear range
[GPa] [D.2.1]
E yc core linear Compressive modulus of elasticity of core transverse [GPa] [D.2.2]
to y-direction in the linear range
G xy core linear In plane shear modulus of core in the linear range [GPa] [D.2.3]
E xt core non-linear Tensile modulus of elasticity of core in x-direction in [GPa] [D.2.1]
the non-linear range
E xc core non-linear Compressive modulus of elasticity of core in x- [GPa] [D.2.2]
direction in the non-linear range
DET NORSKE VERITAS AS