Often materials are subject to forces (loads) when they are used. The mooring lines have to withstand the loads acting on the moored structure in addition to loads acting directly on the mooring components (Bjørnsen 2014). Mechanical engineers calculate those forces and material scientists how materials deform (elongate, compress, and twist) or break as a function of applied load, time, temperature, and other conditions (Virginia.edu 2013).
1.4.1. Tensile Load
The mooring line materials such as chains, steel wire, fiber ropes and anchors mostly work under tensile loads. The mooring line which is connected to the FPSO and the anchor on either sides gets pulled in opposite direction. The largest tensile load is …show more content…
high radiation environments, highly corrosive environments, under high friction conditions, low temperature environments, deep sea environments, or other extreme climate conditions (Ec.europa.eu 2015). To achieve better efficiency and performance careful consideration has to be given to material properties during its design stage. Greater importance has to be given to those material properties exhibiting better resistance to tensile, bending and torsional …show more content…
• Minimum Density to be 7.8 kgm3 (Azom.com 2015)
• Fracture toughness – 112 to 278 Mpam^0.5 (Azom.com 2015)
• Tensile strength – 480 to 620 MPa (Azom.com 2015) Figure 2.2 : CES graph of Tensile strength/Density vs Price
2.1.2. Polyester ropes
Material selection analysis carried out to select the optimal material for chains and anchors in the marine environment showed that POLYESTER/45wt% E-glass fiber, woven fabric composite, biaxial laminate to be the best material considering its material properties as well as its price. Figure 2.3 : CES graph of Fatigue strength vs Yield strength
The limits of selection are justified below:
• Durability in both fresh and salt water has to be excellent.
• The deepsea ocean temperature is usually between 0 – 3 degree Celsius. Hence the minimum service temperature is chosen as 0 degree Celsius.
• Minimum Tensile strength – 57 MPa (Efunda.com 2015)
• Compressive strength 59 -100 MPa (Efunda.com 2015)
Figure 2.4 : CES graph of Fatigue strength vs