OS-C501

Offshore Standard DNV-OS-C501, November 2013
Sec.7 Joints and interfaces – Page 131
1 General
1.1 Introduction
SECTION 7 JOINTS AND INTERFACES
1.1.1 Joints and interfaces are special sections or components of a structure. They can in principle be analysed
an tested the same way as a structure or component. However, some special considerations are described in the
following sections.
1.1.2 Requirements for joints and interfaces are based on achieving the same level of reliability as the structure
of which it is part.
1.1.3 If metal components are part of a joint or interface, the metal components shall be designed according to
relevant standards for such components. This standard does not cover metal components.
1.2 Joints
1.2.1 Joints are defined here as load bearing connections between structures, components or parts.
1.2.2 Three basic types of joints are considered in this standard:
— laminated joints, i.e. joints fabricated from the same constituent materials as the laminates that are joined,
such as e.g. over-laminations, lap joints, scarf joints etc.
— adhesive joints, i.e. joints between laminates, cores or between laminates and other materials e.g. metals
— mechanical joints, i.e. joints including fasteners, e.g. bolted connections.
1.3 Interfaces
1.3.1 Interfaces are defined here as the area or region where different structures, components or parts meet
each other. All joints have interfaces.
1.3.2 If the interface shall transfer loads it also has the function of a joint. All requirements for joints apply to
such an interface.
1.3.3 A typical interface is the area where the surface of a load bearing structure and a liner meet.
1.4 Thermal properties
1.4.1 The effects of thermal stresses and strains and displacements shall be considered for all joints and
interfaces.
1.5 Examples
1.5.1 Examples of good practise shall be evaluated with great care. The examples are usually given for certain
load and environmental conditions, without stating those explicitly. The qualification and analysis
requirements of this standard shall also be applied joints based on good practise. See also [2.4] on how
experience can be utilised.
2 Joints
2.1 Analysis and testing
2.1.1 The same design rules as applied for the rest of the structure shall be applied to joints, as relevant.
2.1.2 Joints are usually difficult to evaluate, because they have complicated stress fields and the material
properties at the interfaces are difficult to determine.
2.1.3 Joints may be designed according to three different approaches:
— An analytical approach, i.e. the stress/strain levels at all relevant parts of the joint including the interface
are determined by means of a stress analyses (e.g. a FEM-analyses) and compared with the relevant data
on the mechanical strength.
— Design by qualification testing only, i.e. full scale or scaled down samples of the joint are tested under
relevant conditions such that the characteristic strength of the complete joint can be determined.
— A combination of an analytical approach and testing, i.e. the same approach specified in Sec.10 [3] for
updating in combination with full scale component testing.
DET NORSKE VERITAS AS