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The ExcelCalcs website is developed is wholly owned by MoreVision Limited. Their analysis, testing and calculation services have been used for railway vehicles, construction equipment, oil and gas plant, cranes and mechanical items for theme parks since 1995. Click the links below to see some case studies:

  • Finite Element Analysis Services: Stress Analysis, Fatigue Analysis, Vibration Analysis, Seismic Analysis, Thermal Analysis, Impact/Crash Analysis & Optimisation.
  • Structural Testing Services: Strain gauge tests, Accelerometers, Signal Processing & Analysis of Test Results.
  • Calculation Services: Structural Design & Sizing, Bolted Joint Assessment, Welded Joint Assessment, Approval to Industry Codes & Standards, Structural Design Troubleshooting, Failure Investigations, Performance Estimation, System Optimisation, Mechanical Simulation, Mechanism Design, Machine Element Design, Vibration & Damping Control, Mathematical Modelling & Loading Calculations.
  • Training: MoreVision offers a number of training courses.

Our client list includes Shell, Bombardier, Siemens, Volvo and Disney:

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ANIMATION: Railway Failure Investigation
Engineering Services

         
The structural failure of a traction motor mounting bracket occurred in service. Fortunately the motor was prevented from falling onto the tracks by a cardan shaft protection ring thus preventing a catastrophe but the issue was taken very seriously by our client and was quickly elevated to the executive level. The animation shows how the vehicle mounted traction motor drives a cardan shaft which drives the wheels via a bogie mounted gearbox. MoreVision was brought in by the executive engineering managers to devise and implement a technical strategy that would guarantee that no further bracket failures would occur in service. This project covered a period of some 18 months working very closely with the vehicle manufacturer, the service providers, depot staff and test sub-contactors. Our brief was simply:
  • to determine risk mitigation actions to keep the fleet working in service.
  • to develop a long term 'safe-life' solution.

Initial Analysis

Within hours we began to gain an understanding of the problem using a simple finite element model. This showed that the bracket was particularly susceptible to lateral loading. We gained enough understanding of the bracket fatigue prone areas to position number of strain gauges for an investigative on track test.

Initial On-track Testing
     
The test train was taken onto the track in a number of configurations (cardan shaft attached, removed and freewheeling). This would help us determine the relative magnitudes of possible fatigue mechanisms. A spotlight was quickly thrown on the importance of low magnitude but high frequency stresses arising from cardan shaft's out of balance forces. This problem could only get worse with time as the cardan shaft wears.

The problem was exacerbated by the dynamic response of the motor rubber mounts whose resonant frequencies coincided with typical line running speeds. The waterfall plot above shows the strain results in the frequency domain (response is plotted against frequency [x] and speed [y]). It shows the maximum response at the same frequency as the cardan shaft rotational frequency. The set of three overlayed curves above shows strain verses time as the train accelerates from 0 to 200kmph. The top graph shows the raw signal (unfiltered); the middle graph shows the high frequency content of the signal (mainly associated with rotation of the cardan shaft); the bottom graph shows the low frequency content of the raw signal (mainly associated with motor torque effects). Both high frequency and low frequency signals had an influence on fatigue life of the bracket. On-track testing helped us to:

  • understand the most important fatigue driving mechanisms.
  • understand the importance of cardan shaft loading and the dynamic response of the motor on its resilient rubber mounts.
  • determine stress signals for input to crack growth models. This forms the basis of an inspection regime to guarantee passenger safety.
  • redefine new loadcases to develop a long term solution.
Immediate Risk Mitigating Actions

Until a long term solution could be devised and implemented it was necessary to undertake risk mitigation actions to ensure the the fleet was running without any risk to passengers safety. This was possible by establishing a crack inspection regime. Ultra-sound Inspection trials were set up to determine the minimum detectable crack size. Simultaneously, using samples of stress measured during the on-track testing and incorporating stress factor to account for cardan shaft ageing, it was possible to calculate an inspection interval to guarantee detection of a crack before a bracket failure.

Further Risk Mitigating Actions

The safety of the fleet was increased further by introducing a polished weld toe detail. This improved the situation in the following ways:
  • it removes weld toe material (this is inherently poor quality material with many defects and flaws that make it susceptible to fatigue failures).
  • it repositions the maximum stress away from poor quality weld material and into good quality polished parent material. Thus the initiation of crack growth was less likely.
  • it increases inspectability of the bracket (smaller cracks could be reliably detected thus cracks can be repaired sooner and the safety of the fleet is increased).

It was difficult explaining that removal of material from a critical section would result in a fatigue strength improvement but the method was endorsed by supporting finite element analysis and expert papers. The detail was easily and quickly introduced by a drilling and polishing operation.


Moitoring the Fatigue Regime

Joints in the cardan shaft wear with time and increase the amount of out of balance force acting on the traction motor mounting brackets. Our analysis and calculations showed that we needed to decrease the inspection interval to accounted for an ever increasingly aggressive fatigue environment. It was important to monitor the cardan shaft loading by continuous testing of cardan shafts on a balancing machine. The problem was exacerbated when a new risk due to heat damaged rubber motor mounts was identified. Additional stress factors were introduced to account for the new risk and the inspection period was reduced accordingly. Over the monitoring period the inspection regime managed to find a number of cracks which were safely repaired before they became anywhere close to the critical size for fracture of the bracket.

Dynamic Analysis

 
A non-linear dynamic model was developed by a partner in Switzerland to study the dynamic behaviour of the traction motor on its resilient mounts excited by the cardan shaft out of balance forces from 0 to 200kmph. Low speed pitching mode gives peak vertical loading on the motor mounting brackets. High speed yaw mode gives peak longitudinal and lateral loading. All modes of vibration are evident in the plot of bracket forces verses speed. It is notoriously difficult to interpret the results of dynamic analysis and define loadcases for a finite element stress model. The initial approach was to take the maximum loads in each direction and apply them in the most adverse combination. This proved to be too conservative and an alternative approach was developed. It was possible to determine stress time histories at fatigue critical locations using dynamic model output. Damage could then be calculated using rain flow counting methods. Once the approach was developed, design iteration which included the rubber mount manufacturer allowed us to optimise the stiffness and damping characteristics of a new high temperature motor mount. This was to become an important part of the solution.

Long Term Solution

A long term solution is developed comprising:

  • New 'riveted in' reinforced front brackets.
  • Structural enhancements including TIG dressing of weld toes and profiling plates to introduce softener details at weld ends.
  • Inclusion of a dynamically optimised high temperature motor mount.
  • Cardan shafts monitoring and control system.


The solution was developed using predictive analysis techniques and validated by monitoring critical strain gauge locations over some 20,000km. In addition the predicted benefit of a new high temperature rubber motor mount was also supported by on track testing. The final solution has an unmonitored safe life of 30 years.

 
Bolt Failure Investigation
Engineering Services

DESCRIPTION OF THE FAILURE

As always our approach is to propose solution found through understanding the mechanics of failure. A railway vehicle antennae raft is cantilevered the bogie transom by 4 M16 bolts. The bolts had repeatedly failed in service and was considered a severe hazard as a detached raft could in a worst case scenario derail a train and result in loss of life. MoreVision were invited to investigate the failure. The bolt samples were sent to a metallurgical laboratory and examination of the bolt fracture surfaces showed all the characteristics of a fatigue failure. The bolts were renewed every month as a risk mitigation action until the investigation reported its conclusions. MoreVision initially performed bolt fatigue calculations using the loading assumed in the design case. The calculations did not predict a bolt failure so it was suspected that the actual service loads were greater than that assumed for design purposes. Another possibility was that some element in the bolted joint was relaxing giving rise to loss of bolt pretension and a premature fatigue failure.

DESIGN AND CALIBRATION OF STRAIN GAUGE BOLTS

After disappointing performance with commercially available bolt sensors MoreVision devised and produced special test bolts by introducing flats on the shank of the bolts and attaching standard linear gauges (photo on the left). The bolts were calibrated in a laboratory load cell shown in the photo on the right.

BOLT RELAXATION TEST

The test bolts were installed on a stationary vehicle in a depot. During installation the load in the bolt was measured as the bolts were torqued up. The bolt force was measured for a number of hours to see if any element in the joint would relax resulting in a significant loss of bolt pretension and premature fatigue failure. The test concluded that relaxation of the joint was within normal acceptable levels and the threat of bolt pretension loss was ruled out.
DYNAMIC 'HAMMER' TEST

Whilst the the vehicle was stationary in the depot the antennae raft was struck with a rubber hammer allowing the raft to vibrate. The response was also seen by the bolt sensors. A spectrum analysis of the bolt test signals illuminated the frequencies associated with the natural modes of vibration. Closer examination of the phasing of the time signals showed the fundamental 'springboard' mode directly (see plot on left).


ON-TRACK TESTING

The data acquisition equipment and computer were installed in the drivers cab. A test route of over 200miles was considered representative of normal service. It was even possible for the train to remain in service as the data was acquired which helped the client maintain his train availability and service levels.

POST-PROCESSING OF TEST SIGNALS
1) FILTERING NOISE
When all the train systems were started up in the depot it was noticed that some noise was picked up by the strain gauges. The characteristic of this noise was very high frequency (greater than 500Hz). The hammer test has shown that the predominant structural frequency was less than 50Hz so frequencies of over 200Hz were taken out using software filters.
2) DAMAGE CALCULATION
The filtered signals were the assessed using rainflow counting techniques to reduce the signals to stress histograms. The fatigue life could be calculated from the stress histograms.

CONCLUSION
Local vibrations due to the resonant response of the raft resulted in higher levels of load than was assumed in the design loadcase. This gave rise to a premature bolt fatigue failure.

SOLUTION
MoreVision working together with the depot mechanical engineering team devised an end support bracket for the antennae. MoreVision prepared a finite element analysis justification for the new end support bracket together with revised bolt calculations and the solution was also proven by further on track testing.

 
VIDEO: Gas Industry
Engineering Services

What is LNG and how is it stored?


MoreVision supply analysis services to the gas industry and have undertaken structural analysis to validate the of design of liquid natural gas (LNG) storage facilities.

Structural Analysis:

The lining of a vast concrete tank is required to provide a vapour barrier for the entire life of the LNG storage facility. Unfortunately concrete shrinks with age and a special cruciform joint was designed by MoreVision so that the lining could accommodate this movement. The analysis required a complex large deflection plastic analysis.

Pipework Stress Analysis:

Stresses in pipes and pipe attachment points are assessed against the requirements of ASME.

 

Thermal Analysis:

Components are exposed to liquid natural at temperatures down to  -160°C. It was necessary to build thermal models to check the effectiveness of the heat break designs and determine the temperature distribution throughout the tank roof equipment. This was required to ensure that the operational temperature limits of constituent parts are not exceeded or to determine the need for safety guards to protect personnel from extreme heat (or cold).

Typically model includes boundary temperatures, heat fluxes, the relevant conduction properties, convection surface details and radiation surface details.

ANSYS Script Generators

Often a large number of items require assessment and Morevision have developed ANSYS script generators to speed up the process of assessment. Most of the finite element models could be reduced in size by taking benefit of axi-symmetry and the time to complete an analysis was remarkably fast.

 
Oil Industry
Engineering Services
MoreVision supply analysis services to support the oil industry and have undertaken a number of projects to validate of design of oil extraction equipment.

Subsea Equipment Assessment of Trawler Snagging Loads:

Sub-sea oil equipment may be snagged by fishing trawler nets. Our assessment considered if the equipment was capable of withstanding such loads. Forces on the leg joint to the main structure was stressed beyond yield but the analysis showed acceptable levels of plasticity and the permanent set in the leg.

Sleeve Analysis:

These analyses consider one concentric part within another. Its is possible to make use of axisymetric models which allows for very detailed modelling without a massive computational effort. Often it is necessary to use contact elements as an inner part subject to a high internal pressure may expand and be supported by the external part. Sometimes the analysis is used to consider the performance of a seal as each part deflects.

Pipe Stress Analysis:

Stresses in pipes and pipe attachment points is considered to the requirements of ASME.

Valve Stress Analysis:

Valves are subject to enormous pressures, this analysis ensured that stresses remain within the limits prescribed by ASME III.
 
VIDEO: Construction Equipment & Excavators
Engineering Services

MoreVision has a particular expertise in the structural design of construction equipment. We provide the "Design of Construction Equipment" course to leaders in the industry.  We have devised new methods of assessment for our clients and invested in software to speed up the assessment procedure. This software is available for use and/or modification as required by new contracts. 

Kinematics Analysis of an Excavator Arm:
MoreVision built a mathematical model of complete vehicles (see our excavator arm example ). The model could calculate any geometrical configuration of the excavator arm. Digging and dipping forces would be calculated for each geometric configuration. The model calculated geometry envelopes, digging force envelopes and lifting force envelopes. The performance of competitor machines could easily be assessed and compared on a like for like basis because the model was fully parametric.

Assessment of a Loader Arm:
MoreVision developed an ANSYS script to generate a simple beam model of a loader and chassis which could be positioned in any geometric configuration (loading position, raised position etc.). The model was used to determine free body forces acting on each component in the machine (Chassis, arm, links, rods and buckets). The free body forces could be extracted from the beam model and applied to a detailed solid finite element model of each component (the picture opposite shows the arm component). The solid models were used to perform a detailed static strength and fatigue strength checks. A non-linear plastic analysis of this arm was also performed for an overload case to determine the permanent and magnitude of residual stresses.
 
Claas Teleporters:
Claas had acquired a business which manufactured telehandling vehicles. Traditionally telehandling vehicles have been designed without any particular structural design methodology. MoreVision were commissioned to develop a structural design performance specification for the vehicle, this included the telescopic arm and the vehicle chassis. Subsequently a full static and fatigue assessment against the specification was undertaken and a summary of design change recommendations were delivered to the client.
 
VIDEO: Theme Park Engineering
Engineering Services

Fatigue assessment of rollercoasters.
Fatigue assessment of rollercoasters. 
Bruce's articulated head at Disneyland Paris.
Bruce's articulated head at Disneyland Paris.
Pinned articulated joint in wagon at Disnetland Paris.
Pinned articulated joint in wagon at Disneyland Paris.
Pinned joints on the London Eye dummy pods.
Pinned joints on the London Eye dummy pods.

Building and managing a theme park is clearly focused on visitor safety. MoreVision are often called to assess the strength, fatigue strength and safety of new attractions.

The Hong Kong Disneyland Railroad Vehicles

The Hong Kong Disneyland Railroad vehicles carry guests between attractions on the resort and requires extensive analysis to satisfy the local regulatory bodies. The train comprises a loco, tender vehicle and coaches. Each vehicle has its own bogie and wheelsets and all items of equipment required assessment. Finite element analysis and calculations considered the static strength and the fatigue strength of the railroad vehicles. Analysis covered many combinations of vertical loads (tare to crush), longitudinal loads (braking, vehicle recovery) and transverse loads (curving, wind and slope). MoreVision worked closely with the vehicle manufacturers transferring data via the internet. MoreVision gave further support by assisting in the client design scrutiny process.

Static strength and fatigue strength analysis was required for the Main Street Vintage Vehicles in Disneyland's new Hong Kong Resort. These included a paddy wagon and a double deck omnibus vehicle.

MoreVision have done a great deal of railway bodyshell analysis but analysis for the Theme Park industry is actually more like crane design than railway design. MoreVision prepared calculations for TUV approval using German DIN standards. MoreVision were also required to take the calculations through the client scrutiny process.

 

      

The picture above shows Disneyland's 'Catastrophe Canyon' ride. A burning petroleum tanker about to falls onto a crowd of onlookers... a job for Superman? No MoreVision! We undertook a loading analysis and a stress and fatigue assessment of the wagon kingpin joint to ensure spectator safety.

Pinned holddown connection for Indiana's bi-plane at Tokyo DisneySea.Remember when Indiana Jones escaped a band of marauding natives by swimming to his bi-plane floating of a river.  Disney wanted to recreate the feel of the film and bought a identical plane for use in their  'Indiana Jones and the Eye of the Temple' attraction. These planes have a take off speed of 30 miles per hour so the problem given to MoreVision was to stop the plane from taking off in strong winds. We undertook some aerodynamics calculations and designed an anchorage system for the plane.
Pinned hold down connection for Indiana Jones's bi-plane at Tokyo DisneySea.

A market stall cart conceals a giant airbag to break the fall of a stunt man. It was particularly difficult to design a light weight but rigid frame.

Consultancy Projects...
Pinned joints in Volvo loader arm.
Pinned joints in Volvo loader arm.

Pinned joints in Claas Tele-handler.
Pinned joints in Claas Tele-handler.

Bruce's articulated head at Disneyland Paris.
Bruce's articulated head at Disneyland Paris.

Pinned articulated joint in wagon at Disnetland Paris.
Pinned articulated joint in wagon at Disneyland Paris.

Railway rod end investigation.
Railway rod end investigation.

Pinned joints on the London Eye dummy pods.
Pinned joints on the London Eye dummy pods.

Pinned holddown connection for Indiana's bi-plane at Tokyo DisneySea.
Pinned hold down connection for Indiana Jones's bi-plane at Tokyo DisneySea.


Consultancy Projects - Fatigue Analysis Of Welded structures


Finite element stress analysis.
Finite element stress analysis.

Understand fatigue classification of welds.
Understand fatigue classification of welds.

Understand how to select appropriate stress from finite element model for fatigue assessment.
Understand how to select appropriate stress from finite element model for fatigue assessment.

Software developed by MoreVision to take benefit from fatigue enhancement methods (like toe grinding, TIG dressing and stress relieving).
Software developed by MoreVision to take benefit from fatigue enhancement methods (like toe grinding, TIG dressing and stress relieving).

View fatigue classification directly on finite element model.
View fatigue classification directly on finite element model.

View damage directly on finite element model.
View damage directly on finite element model.

Export results to spreadsheet for detailed analysis and verification.
Export results to spreadsheet for detailed analysis and verification.

Fatigue assessment of rollercoasters.
Fatigue assessment of rollercoasters.

Fatigue assessment of railway bodyshells and running gear.
Fatigue assessment of railway bodyshells and running gear.

Our Consultancy Projects - Random Vibration Analysis
Shock loads to meet IEC61373 (category 1 class A).
Shock loads to meet IEC61373 (category 1 class A).

Vibration levels to meet IEC61373 (category 1 class A).
Vibration levels to meet IEC61373 (category 1 class A).

Finite element model.
Finite element model.

Frequency assessment.
Frequency assessment.

Calculation of Acceleration Spectral Densities (ASD)
Calculation of Acceleration Spectral Densities (ASD)

Bolt assessment.
Bolt assessment.

Eurocode 3 fatigue assessment.
Eurocode 3 fatigue assessment.

View fatigue classification directly on finite element model.

View fatigue classification directly on finite element model. Shake table testing and analysis verification.
Shake table testing and analysis verification.
Related Consultancy Work
Strength of composite partitions.
Strength of composite railway vehicle partitions.

Testing of composite panels.
Testing of composite panels (see video).

Tram way composite floor study.
Tram way composite floor study.

Composite construction for toilet module.
Composite panel construction for toilet module.

Dynamic analysis of composite structure.
Dynamic analysis of composite structure.

Rod end investigation.
Rod end investigation.

Thread SCF study
Thread SCF study

Key slot fatigue study
Key slot fatigue study
 

 

 
VIDEO: Lightweight Design & Rail Vehicle Interiors
Engineering Services

Assessment of the interior of a railway vehicle is required to ensure the safety of passengers, particularly in a crash situation. MoreVision have extensive experience in supplying these calculations in particular for the refurbishment of London Underground's 73 tube stock (shown opposite) and the refurbishment of the Stansted Express. In addition MoreVision supports equipment suppliers in the preparation of calculations for new vehicles.

MoreVision has expertise in the analysis of composite honeycomb panel structures. These lightweight materials are commonly used for galley areas, toilet modules, doors and partitions.

The animation opposite shows the first mode of vibration of a ceiling hung steam oven unit made from honeycomb panels (shown transparently to view mounting brackets and body structure). The steam ovens were very heavy and our client was not only concerned about the strength of the honeycomb panels but also the strength of the body structure. Resilient mounting brackets were included to isolate the unit from high frequency vibrations to reduce noise levels in the galley.

Interior Doors, Partitions and Luggage Stacks. The picture opposite shows a finite element model of a full wall partition with a central door and two luggage stacks. It is constructed from composite honeycomb material, glass, aluminium and steel. The assembly included a number of bolted and riveted joints. The model was used for a static strength and fatigue strength check.

Another relatively simple analysis but the strength of the table could be very important in a crash situation

Toilet modules will contain walls, doors and various pieces of equipment that each require assessment.

 
Engineering Management
Engineering Services
On many occasions clients have asked MoreVision to bring their specific  technical expertise to help supervise and support mission critical projects. By working together from the outset and by being specific about requirements we help our clients achieve successful outcomes in managing complex engineering issues.

Given our experience in structural calculations for the railway industry the class 222 project team asked MoreVision to head up the structural design validation process and support them through the Vehicle Acceptance Body design scrutiny process. The whole project involved the co-ordination of project engineers and subcontractor organisations to produce 75 document packages covering the vehicle interior and externally mounted equipment. Initially a guidance document was written and sample documents circulated so that subcontractor has a clear idea of what was required. As documents were supplied an audit process was established which raised over 500 scrutiny comments. Each comment was closed out individually and the document package was submitted to the Vehicle Acceptance Body. The activity was controlled using a database system and reported to the project director on a month by month basis until all documents had been accepted. Typically we would spend one day every fortnight at the clients premises in Belgium to report progress and discuss issues with each system engineer.

It is always late on Friday afternoons when something fails, or something is manufactured incorrectly, or some accident happens. We can't tell you why it is always Friday afternoon but at MoreVision we are well practised at working into the weekend to ensure that a situation is made safe in the short term and if necessary devise plans to ensure that a long term solution. Some cracks were found in the corner of a cross tube which the materials lab had said were formed during the manufacturing process. The cross tubes had been used in a whole fleet of bodyshells and it was necessary to demonstrate to the client that crack growth could not take place when the bodyshells were in service. MoreVision determined the stress levels in the cross tube from the global bodyshell finite element model, then used sub-modelling techniques to determine a detailed stress analysis of the cross tubes. MoreVision's Fracture Mechanics Software was then used to show that there was no danger of the cracks growing in the structure.

 
Processing of Test Signals
Engineering Services

Get the Most Out Of Your Test Data.
 

Rainflow Counting.
The rainflow-counting algorithm is used in the analysis of fatigue data in order to reduce a randomly varying stress into a set of simple stress reversals. It is required to allow the application of Miner's rule in order to assess the fatigue life of a structure subject to complex loading.

Spectral Analysis
A time domain graph shows how a signal changes over time, whereas a frequency domain graph shows how much of the signal lies within each given frequency band over a range of frequencies. A time frequency plot is particularly useful when cyclic loads are run up from start to maximum speed. It can be used to determine which modes of vibration are significant.

 

Filtering
Filtering signals can be particularly useful to remove the effect of signal drifting or remove high frequency noise.

 
Strain Gauge Testing
Engineering Services

Strain Gauge Testing Compliments Our Analysis Services Perfectly
After manufacture test techniques can be used separately or in conjunction with finite element analysis. It is an essential tool for failure investigations or validation of design.
 

DYNAMIC 'HAMMER' TEST
Equipment struck with a rubber hammer will vibrate at its natural frequencies. This response will be seen by the strain gauges and sensors. A spectrum analysis of the test signals will yield the frequencies associated with the natural modes of vibration. Damping characteristics can also be measured in this way.

IN-SERVICE TESTING
The data acquisition equipment and computer can be installed at any location and is self powered. The photo opposite shows an installation in a railway vehicle. Testing does not necessarily mean that equipment needs to be taken out of service. 

DESIGN AND CALIBRATION OF STRAIN GAUGE BOLTS
After disappointing performance with commercially available bolt sensors MoreVision devised and produced special test bolts by introducing flats on the shank of the bolts and attaching standard linear gauges (photo on the left). The bolts were calibrated in a laboratory load cell shown in the photo on the right.

BOLT RELAXATION TEST
Bolted joint performance is a common source of problems for mechanical engineers testing a jointed assembly can help us understand poor joint performance. Preload in bolts can be measured using load cells or strain gauged bolts. It is possible to obtain a preload/torque diagram and joint relaxation over a given time period.

SIGNAL PROCESSING AND ANALYSIS
Once data has been gathered from test the process of analysis of test results and signal processing can begin.
 
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