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The consulting company HL Engineering was established as a sole proprietorship by Helge Larsen in 1988. Helge Larsen is a graduate civil engineer and he also holds a doctor's degree in structural mechanics from the Norwegian University of Science and Technology in Trondheim. He has carried out engineering consultancy services as well as research and development assignments for the offshore industry since 1983 (i.e. for leading oil companies, shipping companies, contractors and consulting companies - both with HL Engineering and in previous employments).

HL Engineering performs consultancy services within structural analyses and has extensive experience from the following types of structures and problems:

• Load-bearing steel structures in mobile offshore units and fixed offshore installations, and also pipe systems, cranes, lifting appliances, buildings and machine parts.
• Various design phases and engineering stages (construction phases, installation phases (marine operations), operational conditions - from conceptual studies to completion).
• Linear and nonlinear static and dynamic FEM-analyses (experience from models with different amount of detail and dimensionality (i.e. 1D, 2D, axisymmetric and 3D models) - and experience from different types of structural analyses like static analyses (i.e linear analyses and nonlinear analyses considering large deflections, plasticity, contact surfaces, etc.), buckling analyses, modal analyses, harmonic analyses, transient dynamic analyses and spectrum analyses (e.g. random vibration analyses for probabilistic analyses of peak response and fatigue damage of slender structures exposed to wind and wave loads)). HL Engineering is a licensed ANSYS Multiphysics user, but the company does also have experience from several other program systems like Abaqus, Sacs, Staad 3, Triflex and Femsol (with Femgen and Femview). Abstract from some analyses are included in "FEM/CFD/FSI-Images" (see the menu).
• Development of advanced analytical design formulas and design methods for special purposes (e.g. dynamic stability of offshore conductors during driving – pull-in of risers and flowline bundles through J-tubes – etc.).
• Conventional hand calculations.
• Global and local analyses.
• Code checks in accordance with relevant regulations and standards (e.g. NPD, DNV, NS, TBK, ANSI-ASME, API, BSI, DIN, EUROCODE) by means of hand calculations; use of computer programs with relevant postprocessors; and development of postprocessors for ANSYS in APDL (Ansys Parametric Design Language).

HL Engineering does also have experience from fluid flow analyses (CFD) and from analyses of fluid/structure-interaction (FSI). Some examples are:

• Use of the CFD program system FLOTRAN for fluid flow analyses. FLOTRAN is included in ANSYS with routines for transfer of pressure from the CFD-model to a model for structural analyses. Abstract from an analysis is included in "FEM/CFD/FSI-Images" (see the menu).
• Development of a system for complete hydrodynamic and structural analyses of drilling rigs, ships, mooring-systems and flexible risers is in progress. The system consists of modules containing theory, procedures and program modules for convenient use of the FEM program system ANSYS for modelling, structural analyses and graphic result presentations. Development of an interface between the program systems ANSYS and WAMIT is included, where (among other factors) hydrodynamic forces, pressures and motions evaluated by WAMIT - a highly recognised panel program for hydrodynamic analyses of three-dimensional bodies exposed to wave loads - is transferred to ANSYS for structural analyses. The project is advanced and interesting. The various modules have reached various degrees of completeness - from drafts to nearly completed versions. Companies in Europe and USA have encouraged us to complete the project, but since the project is time-consuming, we will check the market closer before decisions concerning further developments are made. The project is a co-operation between HL Engineering and Anker-Zemer Engineering AS. (cf. "FEM/CFD/FSI-Images" concerning analysis of mooring-systems and flexible risers in ANSYS)

HL Engineering does also posses tools for analyses within other disciplines:

• Modules for various finite element disciplines - like heat transfer, electromagnetics, electrostatics, acoustics and coupled-field analyses like thermal-stress analyses - are included in ANSYS Multiphysics.

HL Engineering welcome feedback (comments, enquiries, joint venture proposals, etc.) by mail, phone, fax or E-mail.

Last update: Oct. 27, 1998