In this article we look at how ESAComp has been successfully used in the design and development of composite pipes used for challenging engineering applications. FLOWTITE describe their water and waste handling GRP pipes and illustrate ESAComp's use with a case study.
About Flowtite Technology
FLOWTITE Technology AS, based in Norway, are one of the world leaders for GRP pipes satisfying the needs of the water and the waste pipe market for over 40 years. FLOWTITE Technology AS is part of the Saudi Arabian Amiantit Group.
FLOWTITE pipes range from 100 mm to 4000 mm (external dimension control), with thickness varying according to pressure and stiffness. Pipe pressure classes range from 1 to 32 bar, and stiffness classes 2500, 5000 and 10000 Pa (ring bending test). Custom-designed pipes are also available with stiffness tailored to meet the needs of a project.
Serving the clean water and wastewater handling worldwide
Dr. Sebastien DIDIERJEAN, Product R&D Engineer for FLOWTITE Technology tells us how ESAComp is helping in the design of their GRP pipes for the water and waste industry.
"Let's start with a brief description of the GRP pipe construction, the materials along with manufacturing aspects", says Dr. Didierjean. "It's a continuous winding process involving continuous glass-fibres, chopped glass, specially selected fillers and resins. The strength of the pipes is determined by the mixing ratio for the various components."
By using advanced material placement technology, a very compressed laminate is created that maximises the contribution from the basic raw materials. The continuous glass-fibres provide strength to resist the hoop stresses from internal pressure, while the chopped fibres provide resistance to axial stresses, impact, and other loads. Other materials, such as a glass or a polyester veil can be wound into the construction to enhance the abrasion, the chemical resistance and the finishing of the pipe.
"The laminate is of a sandwich construction, with heavily reinforced skins, separated by reinforced core supplemented with specially-selected silica for optimum performance. This construction provides increased stiffness by adding extra thickness, placed near the neutral axis in the core", explains Dr. Didierjean. "We can apply a special inner resin liner for severely corrosive applications, while utilising a standard type resin for the structural and outer portion of the laminate."
What are the design drivers for your products?
The main driver is to produce a product which will be in service for decades or centuries. For that purpose standards have been created to demonstrate such performance.
"In the case of GRP-pipes, these minimum performance requirements fall into both short-term and long-term requirements. The most important of these, and generally specified at the same level of performance in all the previously defined standards is initial ring deflection, long-term ring bending, long-term pressure and strain corrosion capability", explains Dr Didierjean. "FLOWTITE pipes have been rigorously tested to verify conformance to the ASTM D3262, ASTM D3517, AWWA C950 and DIN 16868 requirements."
What do you use ESAComp for?
"I use ESAComp mostly for the definition of coupons for material characterization. The main idea is to design a test that is as representative in term of local mechanical loading as possible", says Dr Didierjean. "ESAComp is used for simulating both the pipe behaviour as well as the coupon behaviour during testing in a universal testing machine."
"Performing a basic simulation (modelling and calculation) is much faster and user-friendly with ESAComp than with FEM software, for example", confirms Dr Didierjean.
Which features of ESAComp do you find particularly useful?
"I found the non-linear ability of ESAComp for composite panels very advanced and useful", says Dr Didierjean.
Do you interface ESAComp to external FE software?
"Yes, we have just started to use ESAComp to post-process some of our ANSYS FE-results", says Dr Didierjean.
Case Study: ESAComp provides non-linear simulation of strains in GRP pipe
FLOWTITE Technology use a parallel plate test to assess ring bending stiffness.
In one of the projects, parallel plate bending is used to assess the quality of pipe liner. The evolution of strains at the bottom of the pipe ring as a function of the deflection were determined. Since the deflection reaches up to 30% of the pipe diameter, it is a non-linear (geometrical) simulation.
Performing the simulation of half the pipe ring in ESAComp was straightforward, and then being able to define an elementary coupon presenting the same level of strain under tensile test.
Linear simulation (max deflection 105 mm)
Non-linear simulation (max deflection 157 mm)
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|Componeering wish to thank FLOWTITE for their time and assistance in helping to write this article and case study.||
Dr. Sebastien DIDIERJEAN,
© 2014 Componeering Inc, by Jo Hussey