Find out about some of the consultancy projects that we have worked on. For reasons of confidentiality we are only able to provide high level descriptions for these projects.
Zentech's experience in the aerospace sector includes consultancy work in addition to bespoke software development projects.
Crack propagation analysis of multi-site defects in a compressor disk to allow comparison of predictions against spin test data. Comparison of cyclic symmetry and full-disk models. Inclusion of non-uniform temperature distribution and mechanical loading. Significant growth of defects achieved (70+mm) between compressor stages.
Crack propagation analysis on a circumferential sector of a bladed disc with steady stress field and a superimposed vibration load. Three initial crack positions were specified. A combination of modal analysis and static stress analysis was used. Non-uniform temperature distributions were included in addition to rotational, mechanical, and aerodynamic loads.
Crack growth analysis in the dovetail region of an engine disc/blade combination including low cycle fatigue loading and high cycle fatigue due to blade flutter.
Zentech's experience in the power generation sector includes consultancy work related to nuclear and conventional power plants.
Fatigue crack growth prediction of initially elliptic cracks in pipeline butt welds and fillet welds (circumferential and axial alignment). A variety of embedded and part-through initial defect positions including multiple initial defects. Inclusion of the effect of different material properties and crack growth laws for cracks that pass across the weld / base material fusion line.
Crack modelling and fatigue and creep crack growth analysis for defects in high temperature nuclear power plant components with the aim of demonstrating extended safe operation of the plant. Analyses included multiple thermal transients (startup, shutdown etc) with j-integral and Ct-integral evaluation.
Analyses of intact and cracked power plant components under pressure load and a series of thermal transients. Analyses involved 3D finite element modelling of multiple crack configurations. Abaqus submodelling method was required for some analyses. Also thermal and pressure analysis of cracks in high temperature headers, including crack growth prediction.
Elastic and limit load analysis of cracked pipe intersections including equal tee and sweepolet configurations.
Elastic and creep analysis of a power plant steam chest.
Elastic and creep (C*) analysis of a fully embedded crack in a thick walled component.
Zentech's experience in in the field of transportation includes projects that cover a variety of infrastructure and vehicle types.
Analysis of structural integrity of tracked vehicles impacting uneven terrain. Explicit analysis with initial cracks at key weld and through-wall locations. Also assessment using a Johnson Cook damage law to allow material failure and defect extension for weld cracks.
Linear and non-linear collapse analysis of a range of crack sizes and locations in a tracked vehicle. Analysis undertaken of multiple crack lengths around a wheel station casting with four crack depths analysed for each crack length. Cracks also considered in other locations. Elastic analyses have been used to determine stress intensity factor distributions. Plastic analyses (with elastic-perfectly-plastic assumption) have been used to determine allowable residual strength criteria. This helps provide a “condemnation criteria” for defects identified on vehicles which are in service.
Analysis of defects in a spherical roller thrust bearing assembly of a cargo vessel. In-service defects had been identified, starting at sub-surface inclusions in the bearing raceway. The cracks then grew sub-surface and approximately parallel to the surface. The analysis work modelled this type of crack growth in order to understand the mechanisms controlling the growth.
Forensic investigation into crack development in bridge roller supports due to thermal cycling and traffic load on the bridge deck. Significant mode II and mode III effects were present in addition to multiple contact surfaces, including contact of the crack faces. Good agreement was shown between the crack growth analysis and observed roller failures.
Zentech's experience in offshore engineering ranges from pipeline and riser analysis to detailed finite element analysis of components.
Fatigue analysis of riser hang-off structure to demonstate 15 years of service life. Nine critical positions of the riser hang-off structure were identified and analysed for fatigue damage.
Enhancement of a subsea software system which was originally developed as part of a JIP.
Multiple projects relating to analysis of riser, umbilical and mooring systems and the design and installation of offshore pipelines. This experience has been gained through installation and operational engineering in the North Sea, Gulf of Mexico, West Africa, and Brazil.
Non-linear finite element analysis of drop-load on a subsea structure. The analysis investigated the guidebase, protection frame, and outlet spools of the structure with regard to their ability to withstand the forces that may be incurred by interaction with seabed operations, particularly fishing, and dropped objects.
British Nuclear Fuels plc / H & G Engineering
For over five years providing an independent analysis and design assessment service at the Waste Packaging and Encapsulation Plant at the Sellafield site; Zentech also assessed static and seismic analysis and design for BNFL's THORP Project.
Foster Wheeler Petroleum Developments
Design check of steel jackets for WEPCO. Other work included dynamic analysis of a submerged articulated tower, pile driving analysis, design of accommodation module for North Alwyn A. Also, design of wellhead jackets for UDECO and ZADCO.
Eden Construction / Multi Design Consultants
Independent assessment of seismic analysis and design of a New Oxide Fuels Complex plant at Preston.
Weld strength assessment under fatigue loading.
Foster Wheeler Power Products
Design check on the foundations of chimney stacks for a smelter in Abu Dhabi.
Lloyd's Register of Shipping
Verification of laying and lifting of offshore steel pipelines.
Woodside Offshore Petroleum (PTY) Ltd
Review and optimisation of the dynamic riser system for Woodside Petroleum's Cossack field offshore Australia; this audit of vendor design calculations included: an independent layout design of a Lazy-S and Steep-S flexible riser system, inter-riser and riser-anchor line clashing study, design optimisation of bend stiffeners, wear and fatigue analysis of risers and assessment of riser turret motion obtained from experimental tank data.
Zentech's experience in pipeline and piping engineering is based on a wide range of projects, including pipe stress analysis (static, seismic, and dynamic), optimisation of snubber supports, development of design methodology for seismic design of plant pipework, design of pipework supports and support steelwork, and pipewhip-rupture. Other related areas of involvement include fatigue life prediction of welds, upheaval buckling, and local stress analysis incorporating the effects of plasticity and creep.
Malaysian Rural Water Supply Authority
Pipe stress analyses on specific areas of pipework to determine compliance with ANSI B31.3.
International Gas Apparatus Ltd
A number of gas transmission offtake stations in Wales (for Powergen) and Hong Kong and new territories were analysed to requirements of IGE/TD/12:1985.
British Oxygen Corporation Cryoplants
Stress analyses using the pipe stress program P10ZTL (program by the Dutch authority 'Dienst Voor Het Stoomwezen').
British Gas plc
Zentech completed analyses for British Gas Scotland for many of their Transmission Regulator Stations; the work was carried out using the program GASP4 which incorporated the stress analysis requirements of IGE/TD/9:1975. Stations analysed included:
- Onthank, Selkirk, Rothes, Tranent, Kilmarnock, Dalkeith, Livingstone, Uddingstone, Nairn, Kirkcaldy (Boglily), Springside, Erskine, Letham, Moss, Armadale, and Old Kilpatrick.
Stations analysed for British Gas West Midlands included Barlaston and Rugby stations; these were analysed to IGE/TD/12:1985 using London Research Station's program SPIRIT; normal, shakedown, and fatigue load cases were considered for the stations.
British Nuclear Fuels plc
The project examined the methods of seismic qualification of pipework and plant in the nuclear industry, including:
- assessment of static and seismic analyses, with soil/structure interaction of the following British Nuclear Fuels plc projects: Pond 5 Bridge, West Treatment Complex, Chiller Annexe, Calder Hall Cooling Towers, THORP Head End Building, Centre Building, Feed Pond, Management Centre, existing and extended Receipt and Storage Facility Buildings
- SIXEP Storage Tanks, Chapel Cross Tank Structure - validation of the computer program RESPECT for the derivation of response spectra applicable to all BNFL projects
- recommendations on use of ASME codes of practice suitable to BNFL classifications e.g., ASME III Division 1, subsections NC (class 2 components), NF (component supports) codes of practice suitable to BNFL classifications
- assessment of seismic analyses of various piping and plant in MASWEP using ADLPipe, Ansys, and PSA5 computer programs.
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