Case Studies — Dynamics, Vibration, Noise & Compliance

Resolving severe structure-borne vibration on a quarry recycling & sieving plant

Severe structural vibration threatened safety and payment. We combined on-site measurement, EMA and FEA to identify frame resonance and incorrect AV mounts, then specified and validated mounts matched to screen throw to restore stable operation.

• Sector: Quarry & aggregates; recycling plant

• Services: Diagnostics; vibration testing; FEA; EMA

• Outcome: Severe vibration eliminated; safe operation restored; payment secured

Reducing excessive vibration to achieve API 619 compliance at a gas compressor unit

Compressor bearing vibration exceeded API 619 limits at a gas pumping station. We identified a 47.2 Hz pulsation exciting frame resonance, verified the root cause with Ansys FEA, then designed rapid frame stiffening and confirmed the fix with EMA/FRF testing.

• Sector: Oil & gas; gas compression / pumping station

• Services: API 619 compliance support; vibration measurement; FEA (Ansys); EMA/FRF testing; model updating; structural stiffening design

• Outcome: Resonance removed near 47.2 Hz; bearing vibration reduced to within API 619 limits; compliance confirmed

Vibration analysis of seismic plinths in a semiconductor cleanroom

A semiconductor client needed assurance that tool plinths would meet vibration requirements after floor construction changes. We carried out 3-axis measurements, PSD / 1/3-octave analysis and 1 Hz bandwidth integration with heel-drop testing, confirming ASML compliance and TEL8 acceptability against VC-D, while identifying horizontal stiffness asymmetry for improvement.

• Sector: Semiconductor manufacturing; cleanroom facilities; precision equipment support structures

• Services: 3-axis vibration assessment; PSD & 1/3-octave analysis; 1 Hz bandwidth integration; VC-D benchmarking; heel-drop testing; stiffness diagnosis; FEA/modal/model updating pathway

• Outcome: ASML plinth compliant; TEL8 plinth acceptable vs VC-D (6.25 µm/s RMS); improvement route defined to address stiffness asymmetry

Industrial vibration monitoring for a forging hammer (due diligence & H&S assurance)

Vibration monitoring was commissioned to support planning due diligence and confirm whether a large forging hammer was transmitting harmful vibration and shock to operators and nearby residents. Measurements showed levels on the operator platform were comparable to the surrounding concrete floor—far lower than expected— because the hammer’s opposing tups produced balanced impacts that largely cancelled transmitted forces.

• Sector: Heavy industry; forging / manufacturing

• Services: Industrial vibration monitoring; vibration & shock measurement; due diligence reporting

• Outcome: Excessive vibration concerns disproven; evidence provided for planning and H&S assurance

Vibration analysis and transport simulation for silica “canes” (Lumenisity — a Microsoft company)

Environmentally Sound Limited performed dynamic modelling of Lumenisity’s silica canes to identify natural frequencies and mode shapes that should be avoided during handling and transport, and to determine packaging clearance requirements. Two support conditions were evaluated at the specified clamp points (200 mm from each end): simply supported and clamped-clamped. We also simulated random transport vibration using the ISTA 3A PSD profile and compared deflection due to random vibration with gravitational sag. The work established the most representative support condition for packaging (simply supported when using compliant sleeves such as Sorbothane), quantified expected deflections, and defined a practical packaging envelope—while also highlighting the need to validate uncertainty in Young’s modulus through testing or modal correlation.

Sector

High-tech manufacturing; fragile precision components; transport vibration / packaging engineering

Services:

Dynamic modelling (natural frequencies & mode shapes); support-condition sensitivity (simply supported vs clamped); gravity sag analysis; random vibration simulation to ISTA 3A PSD; packaging clearance definition; engineering recommendations (orientation, clamping strategy, validation testing)

Key issues:

Identify frequencies to avoid exciting cane modes; determine deflection and packaging clearance under gravity + random vibration; evaluate best transport orientation; assess feasibility of “clamped” transport with compliant sleeves; manage uncertainty in Young’s modulus and validate by physical testing / experimental modal analysis

Outcome:

Simply supported packaging was identified as the most representative condition (Sorbothane/compliant sleeves prevent true clamping). Gravity sag for simply supported support was ~22 mm; three-sigma random vibration deflection to ISTA 3A was ~8.2 mm, giving a combined worst-case clearance requirement of ~30.2 mm using superposition. A validation pathway was defined: measure real vehicle PSDs, then shaker-test and/or modal-test to confirm material properties and update the model for robust packaging design.

Vibration test specification compiled for a zoom lens (tracked vehicle hull mounting)

A customer required a complete, test-house-ready vibration test specification to qualify their zoom lens for mounting on the hull of a tracked vehicle. Environmentally Sound Limited was appointed to compile the specification so an external test house could set up, execute and document the testing consistently, with clear controls to avoid under-test or over-test. The specification aligns with MIL-STD-810G Method 514.6 (Category 20: tracked vehicles, installed equipment) and incorporates ITOP laboratory vibration schedules, defining facilities, instrumentation, safety requirements, axis-by-axis execution, tolerances, monitoring, and pass/fail criteria.

Sector

Defence; vehicle-mounted electro-optical equipment; qualification vibration testing

Services:

Test specification authoring; MIL-STD-810G Method 514.6 interpretation (tracked vehicles); ITOP schedule integration; shaker/slip-table setup definition; instrumentation plan (control + monitor accelerometers); test controls & tolerances; functional check plan; reporting and data requirements

Key issues:

Provide a repeatable procedure for a third-party test house; define random-on-random testing from 5–5000 Hz in three orthogonal axes; specify control tolerances (±3 dB overall, ±6 dB above 500 Hz with limits) and RMS limits; include system checks (low-level sine sweep), response characterisation considerations, and safety/risk controls; ensure traceable recording of control and monitor channels and post-test inspection/functional verification

Outcome:

A complete, signed vibration test specification that the test house could implement directly: fixture and mounting orientation guidance, instrumentation and calibration requirements, step-by-step test execution sequence for vertical/transverse/longitudinal axes, test durations, control/monitoring rules, acceptance criteria, and a defined reporting pack (time histories, PSD/FFT plots, RMS/peaks, environmental logs, inspection findings and pass/fail conclusions).

Two-week ground vibration assessment to BS 5228 — Stoke-on-Trent

A car trading company appointed Environmentally Sound Limited to investigate intermittent workplace vibrations at their premises on Leek Road, Hanley, understood to be associated with activity at a neighbouring metal casting company. Because the most severe events were reported to occur intermittently, we deployed an accelerometer at the closest practical location to the assumed source and recorded ground vibration continuously over a two-week period (2–16 February 2024). Results were processed and reported in terms of Peak Particle Velocity (PPV), then evaluated against building response guideline limits in BS 5228-2.

Sector

Industrial / commercial premises; neighbour vibration complaint investigation

Services:

Ground vibration survey (long-duration monitoring); sensor siting and installation; PPV analysis (mm/s) with frequency identification; assessment against BS 5228-2 building vibration limits; interpretation and reporting with traceable calibration records

Key issues:

Intermittent vibration events requiring extended monitoring; establish measured PPV levels and dominant frequencies; compare measured levels to permitted building vibration limits (BS 5228-2); reconcile measured compliance with observed/experienced vibration on upper floors (potential structural response sensitivity)

Outcome:

Maximum measured PPVs on the ground floor were low (e.g., Z-axis 0.78 mm/s at 12.5 Hz) and were well within BS 5228-2 guideline limits for industrial/heavy commercial buildings. While the client reported unfavourable vibration upstairs, the measured ground-floor vibration levels did not indicate excessive exposure per BS 5228-2, pointing toward building response characteristics (e.g. floor span/ modal behaviour) as the likely driver of perception.

Water wheel shaft failure investigation & repair strategy — Upper Crispbrook Mill

Upper Crispbrook Mill appointed Environmentally Sound Limited to assess the failure of a historic water wheel shaft and to develop a practical repair and prevention strategy. On site we observed the fracture occurred ~25 mm from the wheel face, not at the highest nominal bending location, and the fracture surface showed rust marks at the crack origin plus fatigue beach marks. The morphology indicated the crack propagated through >70% of the cross-section before final overload, confirming the shaft had adequate static capacity in its original condition but was progressively weakened by corrosion–fatigue. We identified the root cause as corrosion-assisted fatigue initiated at a crevice/notch at the wheel/block interface, then produced an engineered remedy centred on a stainless-steel stub shaft and bolted flange arrangement designed to prevent water ingress, restore capacity, and enable inspection-based life management.

Sector

Heritage / industrial restoration; rotating machinery; failure investigation

Services:

Failure investigation & engineering assessment; fracture location/morphology review; corrosion–fatigue mechanism identification; bending stress and fatigue capacity calculations; flange/bolt pattern concept design; bolted joint capacity checks (bolt tension + thread stripping); repair and prevention strategy (materials, sealing, inspection)

Key issues:

Fracture occurred away from nominal peak bending point indicating local stress concentration; wet oxygenated environment causing crevice corrosion; fatigue crack growth to >70% section loss before overload; need for a proportionate repair compatible with a historic installation; ensure robust bolt/thread capacity and practical inspection regime

Outcome:

Root cause confirmed as corrosion-assisted fatigue at a local notch near the mounting block. A practical repair concept was specified: a stainless-steel shaft and flange assembly attached via a bolted interface (e.g. M12 pattern with adequate engagement) to restore bending capacity while protecting the critical wetted region from water ingress. The strategy also defined prevention measures (sealing/drainage, corrosion-resistant materials or sleeves/coatings, improved surface condition) and a planned inspection approach, treating the assembly as a finite-life, inspectable component to avoid recurrence.