Selected passages from our experience:

• In plane stiffness assessment of rigidly and semi-rigidly connected steel U-piles walls.
• Study of roll-over and falling-object protective (ROPS & FOPS) structures.
• Improvement study on a fillet welded beam to end plate joint.
• FEA of Circular Bolted Flange Annulus (CBFA) Connections (Figure 1 and Figure 2) [8].

Figure 1 Main features of CBFA connection geometry.

Figure 2 Side view on the connection with the highlighted contact pairs (between flanges), linear constraint equations (bolts) and multi-point constraints (rapid mesh transition), all are shown.

• FEA of bolted sliding hinge joint for a new type of seismic joint. Contact, friction, plasticity and bolt pre-tension involved static stress/displacement analyses including investigations for misalignment [6, 9 & 10]. Click here (2.6MB) to see how the permanent deformation (i.e. plastic strain) develops in a M30 bolted assembly in finite sliding condition.
• Linear buckling and non-linear static FEA of in-situ large scale buckled aluminium culvert.
• Elastic-plastic static FEA of seven different flexible end plate connections (from HERA Structural Steelwork Connections Guide, R4-100: 1999) [4 & 7].
• Local analysis (i.e. submodelling) of the fillet weld termination.
• Static and modal analysis of spiral steel stairway with the goal to avoid sensitivity of the structure to walking vibrations.
• Elastic-plastic static analysis of experimentally tested welded tee joints.
• Elastic-plastic static FEA of experimentally tested large-scale, welded beam to column connections, which failed either in fillet weld or plastic hinge fracture [5].
• Elastic-plastic static FEA of experimentally tested welded beam to end plate connections including accurate contact and bolt pre-tension modelling.
• Comparative study of stress and strain distribution for two similar (beam to column and beam to end plate) configurations. There is an order of magnitude cost difference between the experimental testing with the setup shown in Figure 3 and Figure 4, while the results are still representative [3].

Figure 3 Beam to column configuration.

Figure 4 Beam to end plate configuration. 410 UB54 from solid elements (C3D8I). The beam has the same mesh in both instances.

• Comparison study amongst different experimentally tested fillet welded beam to end plate configurations with and without weld imperfections (Figure 5) [2]. Selected video clips of in-situ recorded inelastic cyclic tests are shown here (50.2MB) and here (35.6MB). An animation of compressed flange buckling with significant lack of fillet weld cross-sectional area is shown here (6.6MB).

Figure 5 Fine meshed finite element model, showing some attributes of the model used in different steps of the analysis. This model has 352 841 degrees of freedom (C3D8I elements).

• Linear static analysis with emphasis on the welds of rock crushing attachment.
• Non-linear static analysis of the thermal behaviour of a composite steel - concrete deck.
• Limited linear static analysis of aluminium trailer chassis assembly in order to show the most effective strengthening to suppress in-situ fatigue crack initiation sites.
• Non-linear static and buckling analysis of a tubular chord member.
• Influence of weld mesh design on the hot spot stress for a fillet welded tee joint.
• Linear static FEA of exercise cycle frame (fatigue).
• Linear static analysis of fillet welded K joint for hot spot stress fatigue analysis.
• Limited linear static analysis of a quantum-drill frame (of agriculture equipment).
• Dinamic, modal and static analysis of industrial chimney.
• Modal analyses of smaller structures and industrial equipment (e.g. electric motor – pump). Calibration with in-situ experimentally recorded data.
• Linear static analysis of 3D reinforced concrete building.
• Modal analysis of the human tracheo-bronchia for a bio-engineering application [1,13].
• Prototype development of a rock crushing attachment.
• Study the nonlinear static response of eccentric steel cleats (compressed strut to column bolted connection)
• Axisymmetric study of accumulator pressure vessels for fatigue assessment with Professor Adolf Hobbacher, international fatigue expert.
• Assessment of a critical welded part strength – as built versus as designed
• Explicit and implicit analysis of several composite reinforced concrete/steel structures under severe fire [15, 18]

Figure 6 Comparison of Speedfloor slab central sagging in fire. Standard and Explicit solvers versus fire test results.

• Linear static FEA of a segment of a water tank.

References:

[1] A. M. Al-Jumaily, N. Mago, Low frequency analysis of the tracheo-bronchia, BED-Vol. 53, Advances in Bioengineering, ASME 2002.

[2] N. Mago, W. Woerner, C. Clifton, Strength assessment of beam to end plate connections under cyclic inelastic demand, The IIW Asian Pacific International Congress, Singapore, 2002.

[3] W. Woerner, N. Mago, A comparison of different test setups for the earthquake performance evaluation of welded moment resisting connectionsv, The 50^th WTIA Annual Conference and 12^th International TWI Computer Technology in Welding and Manufacturing Conferencex, Sydney, Australia, 2002.

[4] C. Hyland, N. Mago, Improved design of flexible end plate connections, PSSC 2001, Sixth Pacific Structural Steel Conference, Beijing, China, 2001. (The authors have accepted the invitation to submit the journal version of this paper in the “Steel & Composite Structures” International Journal).

[5] N. Mago, W. Scholz, C. Clifton, Elastic-plastic finite element study of rigid welded beam to column connections from different weld and parent metal, The IIW Asian Pacific International Congress, Melbourne, Australia, 2000.

[6] N. Mago, Finite element analysis of sliding hinge joint, HERA Report R4-110, 2002.

[7] Co-author of HERA Report R8-21, R8-23 and author of a number of FEA analysis related internal reports.

[8] HERA Steel Design Construction Bulletin (DCB) No. 65, 66 and 67

[9] HERA Steel Design Construction Bulletin (DCB) No. 68.

[10] C. Clifton, J. Butterworth, N. Mago, Two new semi-rigid joints for moment-resisting steel frames, The Inaugural New Zealand Metals Industry Conference, Rotorua, 2002.

[11] S. Dunica, B. Kolundzija and M. Nandor, Elastoplastic analysis of slabs supported by columns, 2^nd RILEM International Conference on “Diagnosis of concrete structures”, Strbske pleso, Slovakia, 1996.

[12] N. Mago, Finite element analysis of moment end plate connections, HERA Report R4-117 2nd revision, 2003.

[13] A. M. Al-Jumaily, N. Mago, Refined models for the Low Frequency Characteristics of the Trachea-Bronchia, BED-Vol. 53, Advances in Bioengineering, ASME 2003. Paper number IMECE2003-41740

[14] N. Mago, G C. Clifton, Bolted sliding hinge behaviour under cyclic loading, NAFEMS World Congress, Orlando, Florida, USA, 2003.

[15] N. Mago, G C Clifton, Stage 2 Development of the Slab Panel Design Procedure, HERA Report R4-118, 2004.

[16] N. Mago, G C Clifton, Modelling of Slab Panels in Severe Fires, HERA DCB No 74, 2003.

[17] N. Mago, Verification of revised MEP procedure, HERA Report R4-120, 2003.

[18] N. Mago, G C. Clifton, Realistic simulation of reinforced concrete slabs under sever fire attack, NAFEMS World Congress, Malta, 2005.

[19] N Mago, G C Clifton, M Feeney and T Porter: Performance of an Office Building in Fire, 2008 Abaqus User’s Conference, Rhode Island, USA.

[20] N. Mago, G C Clifton, Investigation of the slab participation in moment resisting steel frames, HERA Report R4-140, 2008.