Steel Reinforcement and Load-Transfer Analysis

# Senior Mechanical / Polymer Engineer – HDPE, Steel Reinforcement, FEA and Fabrication Liquimech Group is an Australian company that designs, engineers and manufactures liquid management infrastructure and specialised equipment for the mining, industrial, civil construction and government sectors. We are seeking an experienced Senior Mechanical Engineer, Polymer Engineer or similarly qualified engineering specialist with proven experience in fabricated HDPE structures, steel reinforcement systems and nonlinear finite element analysis. The primary objective of this engagement is to improve the structural performance of fabricated HDPE products by developing practical steel reinforcement, support and load-transfer systems. This is not a civil engineering role, a general structural drafting role or a basic CAD modelling position. We require someone who understands how HDPE behaves as a flexible, time-dependent material and who can design steel and HDPE components to work together without creating excessive local stress, deformation, creep, restraint or premature failure. This is intended to become an ongoing relationship for the right engineer. ## Primary Objective Liquimech designs and manufactures products that combine fabricated HDPE components with steel frames, supports, collars, lifting systems and reinforcement structures. We require an engineer who can investigate and develop practical ways to improve: * HDPE strength and stiffness * Shape retention * Resistance to ovalisation * Resistance to local deformation * Resistance to buckling * Load distribution * Support around penetrations and connections * Lifting and transport capability * Long-term structural performance * Steel-to-HDPE load transfer * Fabrication efficiency * Product durability The engineer must determine how steel can be used effectively without creating concentrated loads, rigid restraint points or interface conditions that reduce the long-term reliability of the HDPE. ## Typical Products and Applications Projects may include: * Fabricated HDPE tanks * HDPE vessels * Large-diameter HDPE pipe structures * HDPE pipe-based equipment * HDPE pontoons * Floating pump support systems * HDPE lined steel structures * HDPE and steel skids * Pump support structures * Pipework support systems * Standpipes and filling systems * HDPE penetrations and nozzles * Steel reinforcement frames * Steel collars and support rings * Lifting frames * Transport restraints * Internal and external support systems * Custom mining and industrial equipment ## Key Responsibilities The successful engineer may be required to: * Review existing Liquimech HDPE and steel designs * Identify likely failure, deformation and fatigue modes * Identify weak areas in fabricated HDPE structures * Assess local deformation and ovalisation * Assess long-term creep and stress relaxation * Develop steel reinforcement concepts * Develop HDPE reinforcement concepts * Compare steel, HDPE and combined reinforcement options * Develop practical load-transfer arrangements * Design steel frames, collars, saddles, ribs and supports * Design bolted, clamped and mechanically retained interfaces * Assess local bearing and contact pressure * Assess thermal movement between steel and HDPE * Determine where controlled movement or sliding is required * Determine where rigid restraint is suitable or unsuitable * Complete preliminary hand calculations * Build and review nonlinear FEA models * Optimise designs based on analysis results * Develop practical fabrication details * Produce SolidWorks models * Produce workshop-ready fabrication drawings * Produce bills of materials and cut lists * Prepare engineering calculation and FEA reports * Provide documentation suitable for independent engineering review ## Required HDPE Knowledge Applicants must have demonstrated knowledge of HDPE or similar thermoplastic materials. Relevant experience should include: * Fabricated HDPE tanks or vessels * Large-diameter HDPE pipe * Thermoplastic structural products * HDPE plate fabrication * Extrusion welding * Butt welding * Fabricated HDPE joints * Local reinforcement of HDPE * HDPE flanges and penetrations * Mechanical fastening of thermoplastic components * Support of flexible polymer structures * Thermoplastic creep * Stress relaxation * Temperature-dependent behaviour * Long-term versus short-term material properties * Local buckling * Ovalisation * Large deformation * Environmental stress considerations * Repeated or cyclic loading Applicants must understand that HDPE cannot be treated as a steel structure with a lower elastic modulus. ## Steel-to-HDPE Interface Knowledge The primary focus of the role is the relationship between steel and HDPE. Applicants must understand and be able to assess: * Differential stiffness * Differential thermal expansion * Long-term creep of HDPE against rigid steel components * Stress relaxation * Local bearing pressure * Concentrated loading * Edge loading * Point loading * Friction and sliding * Clamped interfaces * Bolted interfaces * Backing plates * Steel support rings * Steel collars * Steel saddles * Steel frames * Isolation pads * Replaceable wear strips * Load-spreading plates * Controlled movement * Rigid restraint * Steel corrosion protection * Galvanising considerations * Fabrication tolerances * Assembly tolerances * Maintenance and replacement access The engineer must be capable of deciding whether the steel should: * Carry the primary structural load * Stabilise the HDPE * Limit deformation * Distribute concentrated loads * Reinforce penetrations * Restrain movement * Permit controlled sliding * Support lifting and transport loads * Act independently from the HDPE ## FEA Requirements The successful applicant must have strong practical experience in nonlinear finite element analysis. Relevant capability includes: * Nonlinear material modelling * Geometric nonlinearity * Large-displacement analysis * Contact analysis * Sliding interfaces * Frictional contact * Steel-to-HDPE interaction * Short-term polymer behaviour * Long-term polymer behaviour * Creep assessment * Local buckling * Global stability * Local deformation * Ovalisation * Contact pressure * Thermal loading * Repeated loading * Sensitivity analysis * Mesh refinement * Mesh convergence * Appropriate element selection * Appropriate boundary conditions * Realistic restraint assumptions * Validation using hand calculations or simplified models The applicant must be able to explain: * Why the selected material model is appropriate * Why the selected modulus and material properties are appropriate * Whether short-term or long-term properties have been used * How boundary conditions have been established * How contact has been represented * How friction has been considered * How mesh convergence has been checked * Whether high stresses are genuine or numerical singularities * How FEA results have been independently validated * The limitations of the analysis Experience with ANSYS, Abaqus or an equivalent advanced nonlinear FEA package is highly regarded. SolidWorks Simulation experience alone may not be sufficient unless the applicant can demonstrate appropriate nonlinear polymer, contact and creep analysis capability. ## Practical Fabrication Knowledge The engineer must understand how the proposed design will actually be manufactured. Required or highly regarded knowledge includes: * HDPE butt welding * HDPE extrusion welding * HDPE plate fabrication * Steel fabrication * Structural steel sections * Plate rolling * Laser cutting * Folding * Machining * Weld preparation * Weld access * Fabrication sequencing * Assembly sequencing * Fit-up allowances * Fabrication tolerances * Weld distortion * Steel coating systems * Hot-dip galvanising * Mechanical fastening * Clamping systems * Isolation between dissimilar materials * Installation clearances * Site assembly * Maintenance access * Transport limitations * Lifting requirements * Commercial material availability The engineer must not produce designs that are theoretically acceptable but unnecessarily difficult, expensive or impractical to fabricate. ## Design Approach The successful applicant will be expected to: * Understand the product function * Identify the critical design loads * Identify likely failure modes * Establish suitable design assumptions * Complete preliminary checks before detailed FEA * Develop more than one practical reinforcement concept where appropriate * Compare the concepts * Recommend the most efficient solution * Complete detailed analysis * Refine the design * Produce workshop-ready documentation * Clearly identify assumptions, exclusions and unresolved risks The engineer must be willing to challenge unsuitable concepts and recommend simpler or more practical alternatives where appropriate. ## Typical Load Cases Projects may require assessment of: * Hydrostatic loading * Internal liquid pressure * External pressure * Vacuum conditions * Self-weight * Equipment loads * Pipework loads * Lifting loads * Transport loads * Braking and acceleration loads * Wind loading * Cyclonic wind loading * Handling loads * Installation loads * Operating vibration * Repeated loading * Thermal expansion * Uneven support conditions * Local impact * Temporary fabrication or transport conditions ## Software Requirements Applicants should be experienced with: * SolidWorks * ANSYS, Abaqus or equivalent nonlinear FEA software * Engineering calculation software or spreadsheets * Technical report preparation Applicants must be capable of providing native files, not only screenshots or exported PDFs. ## Required Deliverables Depending on the project, deliverables may include: * Existing design review * Design criteria * Load-case schedule * Failure-mode review * Material property schedule * Preliminary hand calculations * Concept sketches * Alternative reinforcement arrangements * Concept comparison * Native SolidWorks files * Native FEA files * STEP files * PDF general arrangement drawings * PDF fabrication drawings * DXF files * Bills of materials * Cut lists * Weld details * Assembly details * FEA assumptions * Material models * Boundary-condition summary * Contact definition summary * Mesh information * Mesh-convergence results * Stress results * Displacement results * Buckling results * Contact-pressure results * Creep or long-term deformation results * Recommended design modifications * Engineering calculation report * FEA report * Design-risk register * Clearly stated assumptions and exclusions ## Engineering Qualifications Applicants should hold a recognised qualification in one or more of the following: * Mechanical engineering * Polymer engineering * Materials engineering * Product design engineering * Manufacturing engineering * A closely related engineering discipline Applicants with a civil engineering background will only be considered where they can demonstrate substantial relevant experience in fabricated HDPE products, thermoplastic structures and steel-to-polymer interface design. General building, concrete or civil infrastructure experience alone is not relevant to this role. ## Preferred Experience The following experience will be highly regarded: * Fabricated HDPE tanks * Thermoplastic vessels * Large-diameter HDPE structures * Steel-supported HDPE systems * Mining equipment * Pump systems * Liquid management equipment * Pontoons * Floating equipment * Industrial skids * Tank support systems * Lifting frames * Pipework support systems * Australian manufacturing * Australian Standards * Third-party engineering review ## Australian Engineering Review Formal Australian engineering certification may be completed by Liquimech’s appointed Australian engineers where required. The successful applicant’s design and analysis must therefore be: * Complete * Transparent * Technically defensible * Properly documented * Suitable for independent review * Supported by native calculation and FEA files * Capable of being reviewed without substantial redesign ## Working Arrangement This is a remote freelance engagement. The successful applicant must provide: * Strong written English * Clear technical communication * Reliable availability * Accurate time recording * Regular progress updates * Prompt identification of missing information * Prompt identification of technical risks * Proper file management * Proper revision control * Some availability during Perth, Western Australia business hours * Willingness to participate in online design reviews * Willingness to communicate with Liquimech’s workshop and engineering personnel ## Confidentiality and Intellectual Property All models, drawings, calculations, reports, concepts, files and intellectual property produced under the engagement will remain the property of Liquimech Group. The successful applicant must agree to: * Maintain confidentiality * Not publish Liquimech work * Not use Liquimech designs in public portfolios * Not contact Liquimech clients or suppliers directly unless authorised * Not subcontract the work without prior written approval * Provide all native files * Upload working files regularly * Return all project information at the completion of the engagement ## Initial Paid Technical Assessment Shortlisted applicants will be offered a paid technical assessment. The assessment may involve reviewing a simplified steel and HDPE assembly and completing some or all of the following: * Identify likely HDPE deformation modes * Identify likely failure modes * Identify unsuitable steel restraint points * Review the proposed steel-to-HDPE interface * Recommend improved reinforcement concepts * Establish suitable load cases * Complete preliminary calculations * Propose an appropriate FEA methodology * Complete a representative nonlinear analysis * Review contact pressure * Review local deformation * Review ovalisation * Recommend design changes * Explain how the concept would be fabricated * Produce a representative fabrication drawing * Prepare a concise engineering summary The assessment will focus on engineering judgement, HDPE knowledge, nonlinear analysis, steel-to-polymer interaction and practical fabrication capability. A visually attractive FEA result without sound assumptions, validation and practical detail will not be considered acceptable. ## How to Apply Please provide: 1. Your hourly rate in USD. 2. Your location and time zone. 3. Your engineering qualifications. 4. Your years of mechanical design experience. 5. Your years of HDPE or thermoplastic design experience. 6. Your years of nonlinear FEA experience. 7. The FEA software you use. 8. Your level of SolidWorks experience. 9. Examples of fabricated HDPE products you have personally designed. 10. Examples of steel-reinforced HDPE structures you have personally designed. 11. Examples of thermoplastic tanks, vessels, pontoons, pipe structures or similar equipment. 12. Examples of nonlinear FEA reports you personally prepared. 13. Examples of workshop or fabrication drawings you personally produced. 14. Details of your experience with HDPE welding and fabrication. 15. Details of your experience with steel fabrication. 16. Details of your experience with steel-to-polymer interfaces. 17. Details of your experience with creep or time-dependent polymer analysis. 18. Details of any Australian Standards experience. 19. Your normal weekly availability. 20. Your available overlap with Perth, Western Australia business hours. 21. Confirmation that you can provide all native CAD, calculation and FEA files. 22. Confirmation that you personally complete the work. 23. Confirmation that you will not subcontract the work without written approval. 24. Confirmation that you are prepared to complete a paid technical assessment. Please begin your application with the words: **Steel Reinforced HDPE** Generic applications will not be considered. Applicants who only provide steel structures, buildings, architectural models, rendered images, academic assignments or basic linear FEA screenshots will not be shortlisted.