How do applied stresses and residual stresses interact?

Paper from ECOROLL AG Tool Technology

Surface properties - Subsurface properties - Residual stresses - Information/Know-how.

How to estimate the effect of residual stresses.

It is not always easy to estimate the effect of residual stresses during the design phase. It is generally known that residual stresses can significantly influence the service life of components. For this reason, processes such as deep rolling, machine hammer peening, and shot peening are used repeatedly. They generate the necessary compressive residual stresses in the subsurface area and are thus largely responsible for extending the service life of a dynamically loaded component. However, it is still difficult for design departments to take this into account in their calculations. In the following, we will explain how an initial rough estimate can be made and how residual stresses actually affect dynamic strength.

Residual stresses are internal stresses in the structure.
First, we need to understand what residual stresses actually are. Residual stresses are stresses in the microstructure of a component that are present even when no external forces, torques, or temperature gradients are acting on the component, i.e., when the component is completely free of any load. They can occur anywhere in the manufacturing chain and are the result of mechanical and thermal loads during the individual manufacturing steps. For example, so-called casting stresses can arise during casting because the component cools at different rates in different areas. They can arise during machining due to the strong thermo-mechanical stresses caused by the cutting edge, or they can be generated specifically by means of mechanical solidification processes.

As with residual stresses, intrinsic stresses are generally divided into tensile and compressive stresses. Tensile stresses are described mathematically by a positive figure, while compressive stresses are described by a negative figure. In general terms, it can be said that compressive stresses extend the service life of components, while tensile stresses shorten it.

The reason for this is the initiation of cracks by stress peaks. If the tensile stress in one part in a component is too great, a crack will form at this point. Initially, this crack is small, but it grows larger and larger with further loading until the component finally fails. In simple terms, tensile residual stresses pull on the crack, causing it to grow faster. Compressive residual stresses counteract crack propagation and thus slow down crack growth.

Superposition of load stresses and residual stresses.
Like all stresses, residual stresses can also be superimposed with load stresses. This can be done by simple superposition. In other words, the load and residual stresses are simply added together. The result is then a resulting stress.

We can easily understand this using the example of a uniaxial stress state, i.e., a bar. If a uniaxial tensile stress of sload = 600 MPa is applied to this component and it has no residual stress, then the resulting stress is still sres = 600 MPa. If, on the other hand, the bar is subjected to a compressive residual stress of sESP = -200 MPa in the same direction, then mathematically the 200 MPa is subtracted from the 600 MPa and the resulting stress is sRes = 400 MPa. A bar that would fail at 550 MPa, for example, could therefore be used in the second case, but not in the first case. This explains the effect of residual stresses in a comprehensible way.

But what about a multi-axial stress state? Here, of course, the concept must be applied to the entire stress tensor. In this case, the corresponding residual stress values must be used for each component of the stress tensor. For example, in the x-direction, the principal stress of s(x) must be calculated with the principal stresses in the x-direction. If this is done for all components as well as the shear stresses, the result is a complete stress tensor with principal stresses.*

In order to estimate the effect on strength, the concepts of equivalent stress can be applied. This compresses the stress tensor to a single stress value and allows it to be compared with the strength characteristics from the stress-strain diagram.

Of course, the method presented here is not a complete service life assessment, and further calculations or tests must always be carried out to estimate dynamic strength. However, the method presented here allows the effect of residual stresses to be roughly estimated. Effects such as additional strengthening of the microstructure or residual stress reduction during loading are not taken into account, however.

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* Mörke, T.: Randzonenanalyse zur Bestimmung mechanischer Belastungen im Lebenszyklus spanend gefertigter Bauteile. Doctoral thesis, Leibniz University Hannover, 2016.

@PresseBox @UnnGmbh #Ecoroll #Stress #Manufacturing

Young stress analysis!

The Young Stress Analyst Competition (YSA20) will take place as an independent event, online via Zoom on Wednesday 16th September 2020.

Although the British Society for Strain Measurement (BSSM) had to cancel their conference this year, they are opening the Young Stress Analyst of the year 2020 competition (YSA20) and will run this as a purely online event this year.

They want to give a forum for early career researchers to share their work in this annual competition, despite the ongoing and understandable restrictions on face-to-face conferences.

Many were hoping to compete this year and so they decided to run an online event in September for the finalists of YSA20.

To enter applications should be submitted by 10th August, ready for peer review. A shortlist of 4 finalists will be invited to present their work during an online event held in September.

@BSSMStrain #YSA20 

Structural health monitoring.

New from Leine Linde and available with full support from Mclennan, the ESR strain sensor is measurement concept that offers a novel alternative to conventional strain gauges through improved accuracy, signal quality and especially durability. Particularly suited to large-scale machine structural health tasks where load or force needs to be reliably monitored, the ESR utilises Leine Linde’s robust optical encoder technology coupled to a mechanical measuring arm arrangement which is fixed to the structure’s strain-prone components.

With its integral EnDAT bi-directional digital interface, the ESR’s high resolution output of 0.025 μɛ (μm/m) can be connected to almost all available machine control systems and additionally can offer stored application-specific data that may be used for machine functions, for instance for safety or other operational tasks. Application areas for the ESR can include but are not restricted to structural monitoring on bridges, cranes and towers, wind turbine blades, large machine frames, construction equipment, bulk material conveying lines and more.

The strain sensor arm design features passive temperature compensation, and its stress-free measurement principle offers a practically unlimited operation life. Operational temperature can be designed for -40°C to +100°C and the measurement range covers ± 5 000 µɛ with a working range of ± 17 500 µɛ. The unit will fit into a volume envelope of approximately 340 x 80 x 85 mm (L x W x H). The ESR also boasts an impressive shock and vibration rating to ISO 60068-2-26, and its IP66 environmental rating offers trouble-free use in harsh environmental conditions.

For use as a temporary strain measurement tool or for permanent installation, the ESR’s measuring arm design and mechanical interface can be custom-adapted to the application with variant options and accessories available for adhesive, screw, or magnet installation. Other options include various measurement reports, quality control certifications or DAkkS calibration.

 #Mclennan #BAS @LeineLinde @mepaxIntPR

Strain sensors in concrete pumps.

The trend on truck-mounted concrete pumps is for greater reach with less weight. Technical advances at Schwing are currently making it one of the market leaders in this field. In order to raise operator comfort levels on truck-mounted concrete pumps with large booms, the company has launched an innovative vibration damping system. In partnership with Baumer Electric, the company has developed a new strain sensor with an IP69K protection rating and an exceptionally broad measuring range to provide precise signaling of deflections as they occur in the boom.

Since its formation in the 1930s, they have been designing, constructing and selling pumps, machines and plant equipment for the production, transport and reprocessing of concrete: batching plants, truck-mixers, stationary and truck-mounted concrete pumps as well as recycling plants. Whether concreting a swimming pool in the front garden of a family home or realizing prestigious public projects such as the One World Trade Center in New York (USA), or the third Bosporus bridge in Turkey, the machines and plant are deployed wherever concrete is used to provide permanent stability. With six manufacturing sites and subsidiaries or representatives in more than 100 countries, the company provides efficient, reliable and long-term solutions throughout the world. Extensive in-house production capacity for core components guarantees strict inspection processes and high product quality.

Truck-mounted concrete pumps of various sizes and types are manufactured at sites in Herne (D), Chennai (Ind), and Sao Paulo (BZ). The models with the longest placing booms are manufactured at the Group’s German headquarters. With a new boom drive concept, high-strength steel, less weight, and more operator comfort, they are Schwing’s answer to the market's increasing demands in terms of economics, ecology and ergonomics.

Modern placing booms have a reach of almost 65 meters. With highly efficient twin cylinder piston pumps and a pressure of up to 85 bar, they pump concrete at up to 164 m3 per hour. This obviously causes vibrations in the boom. In order to be able to offer end users improved operator comfort at the end hose, Schwing has developed an innovative vibration damping concept which has included a complete revision of the hydraulic elements. A precision transducer was required which could pick up the elongations from the signal boom caused by movement of the whole placing boom, and which would then transmit the command variables for the vibration damping. A force sensor would have to be mechanically built into the direct flow of forces from the arm and then exactly matched to the machine geometry. It was possible to significantly reduce the development effort by absorbing the movement over the elongation. The effect of a force always produces elongations in a mechanical structure. These elongations depend on the geometry of the structure to be measured and the modulus of elasticity.

“We developed a customer-specific, innovative strain sensor in close collaboration with Baumer Electric AG which comfortably overcomes all the challenges,” explains Reiner Vierkotten, Senior Engineer Control Systems at Schwing GmbH. “The new high-strength steels we have used allow the mechanical stresses and elongations to take place in higher areas than in previously used materials. Conventional strain sensors cannot operate in these areas.”

A completely new set of sensor mechanics was developed using FEM simulations with a measuring range of ± 2000 µm/m. The easy-to-mount sensor with long-term seal functions perfectly in multi-shift operation in spite of the tough conditions on building sites. It is calibrated at the factory which speeds up installation and any possible replacement work. The new sensor, with its on-board electronics, supplies a high-resolution digital CANopen signal directly to the truck-mounted concrete pump’s control system.

Compared to force sensors, which have to be precisely adjusted to the machine geometry, the strain sensor can be easily mounted at the optimum position with just two bolts. This does not affect the structure of the machine, save times in development and makes mounting easy. The robust design of the sensor makes it impervious to shocks, impacts, and other mechanical influences and is therefore ideal for use in the construction environment. At the same time, it is very gentle, reacts quickly, and can accurately detect even the slightest elongation or compression. It is resistant to wind and weather due to its a corrosion-resistant housing. With a certificated protection class of IP69K, its seal is absolutely guaranteed and can be cleaned with high-pressure or steam cleaning systems.

“We are very pleased with our collaboration,” confirms Vierkotten. “The innovative damping system is also available for the latest S 65 SXF truck-mounted concrete pump from SCHWING which was launched at the beginning of 2018 at the World of Concrete trade fair in Las Vegas. Following comprehensive prototype testing and optimization during the development phases, the new DST55R strain sensor was successfully put into volume production by Baumer. We can imagine using Baumer sensors for future projects on our truck-mounted concrete pumps.”

@BaumerGroup #PAuto #Construction

Measuring stress under pressure!

When Terex Pegson® MPS needed a reliable and flexible system to measure stress on its LJ5139 stone crushing machine, it turned to HBM to provide a comprehensive and effective solution.

Following a thorough study of the issues faced by Terex Pegson® MPS, HBM specified its rugged DAQ, SomatXR series, which is particularly suitable for use in harsh environments. To compliment this package, HBM also suggested the Somat MX1615B-R module and related accessories, which included RF-9 strain gauge rosettes.

Given the demanding environment, it was important that Terex Pegson® MPS specified the correct equipment. “Often faced with wet and arduous conditions, the ability to operate reliably under harsh conditions and sudden impacts was a key consideration for the customer when it came to suggesting the SomatXR system” explains Gregg Todd, HBM Mobile Data Acquisition Specialist.

The powerful SomatXR data acquisition system is specifically developed for use in harsh environments. The modules provide a wide temperature range and are protected from humidity, dust, shock and vibration.

The data acquisition system provides a web interface for simple operation without any software installation. This allows for convenient channel parameterisation, monitoring of measurement jobs and visualisation of measured data far away from the measuring point. This was a particularly significant feature for Terex® MPS, given the nature of the measurement task.

Another factor which was taken into consideration when specifying the Somat XR series was the operating conditions. For instance, when operating under such extreme conditions, it’s often hard to anticipate all of the problems that may occur, such as losing measurement data due to unforeseen events, such as a power failure. The SomatXR system enables data to be continuously recorded. This means that should a failure interrupt a test, recorded data up until that point will be saved. This was a particularly relevant feature in terms of the long term tests, typically performed by Terex® MPS.

HBM data acquisition systems are suitable for a wide range of mobile testing applications. Despite the immense load requirements and extreme environmental conditions, HBM was able to provide Terex® MPS with a reliable and flexible solution.

In addition to specifying and supplying Terex® MPS with a system to meet its needs, HBM also provided engineers with valuable training and continued support, where needed.

@HBMmeasurement #PAuto #Mining

Everything you should know about Aircraft Structural Testing!

As airframe structures must be thoroughly tested to ensure top performance through its operational life, ‘Everything you should know about Aircraft Structural Testing’, a webinar from HBM, is suitable for structural engineers who are working on the development of modern aircraft.

Webinar scheduled for June 27^th 2017 at 9am (GMT)

When it comes to aircraft design, extensive stress, quality and safety testing are all necessary to make sure the design will work, as even the tiniest defect can cost lives.

Split into four comprehensive categories, this webinar will start with looking at some of the reasons and common drivers behind aircraft structural testing and will move on to high-channel count testing. The webinar will then look at typical requirements of the testing engineers and a sketch of the workflow. Following this, it will conclude with a short introduction of CP52, the communications processor and participants will be shown a live demonstration with Catman Enterprise software suite, MGCplus data acquisition system and a wing model.

The MGCPlus from HBM supports a wide spectrum of sensors, transducers, fieldbus connections and standard PC interfaces, making it a suitable choice for aircraft structural testing. In addition, its modular design ensures that it can be easily expanded or modified should requirements change.

Structural tests, even on a prototype design, can often require the monitoring of many thousands of measuring points and this is where reliable, secure and flexible software is important.

Catman software, which can be used for configuring, visualizing and analyzing measurement, is specifically developed for high-channel count measurements using the MGCPlus DAQ. Secure, flexible and reliable, Catman software is suitable for projects ranging from as few as 30 measuring points to large scale tests demanding up to 20,000.

Each webinar, which normally takes a maximum of one hour, can be easily accessed at a later date or simply used as a refresher course. As an added benefit, all registered participants will receive a link to the webinar, via email, after the presentation. All HBM webinars are free of charge. However, spaces are limited and are available on a first come, first served basis.

Reserve your space by booking here.

Option for high-temperature experimental stress analysis.

Micro-Measurements®, part of the Vishay Group, have a new, optional pre-attached Teflon leadwire for its CEA- and WK-series strain gauges, Option SP35, in support of high-temperature stress analysis requirements to +400°F (+204°C).

A key benefit in the specification of pre-cabled gages for stress analysis is their efficiency during installation. With this new option, Micro-Measurements has extended this benefit into higher application temperatures. New Option SP35 includes ten feet (three meters) of 30-AWG, twisted, etched Teflon leadwires (330-FTE). The etching ensures that any protective coatings applied over the installation will bond and seal to the cable. Gauge leadwires are pre-attached via solder to the CEA- and WK-series strain gages, allowing them to support specific requirements to +350°F (+177°C) and +400°F (+204°C), respectively. Their three-wire quarter bridge configuration cancels any potential cable thermal output which may occur in response to temperature changes.

Option SP35 is ideal for the support of higher temperature stress analyses of automotive and aerospace components, or of any other structural material. It is particularly useful for higher temperature composite materials testing, eliminating the need for soldering on the test article, and thus the possibility of heat damage to sensitive surfaces.

In addition, Option SP35 has no impact on strain gage resistance tolerance or strain range specifications, allowing for continued seamless integration into the application environment. At the same time, it offers a viable leadwire solution with simplified installation requirements. With these combined features, Option SP35 now allows a customer to specify both Micro-Measurements CEA- and WK-series strain gages into an expanded number of higher temperature applications, particularly those where the limitations of traditional pre-gaged vinyl insulated cabling had previously limited their use.

@Strain_Gage #Pauto @VishayIndust

Monitoring bridges in all weathers

RDP products are frequently used to measure movements in the structure of bridges caused by the weight of traffic, environmental conditions and other factors.

Higher traffic loads and corrosion can lead to increased strain in bridge components, such as suspension cable fixing points. It is important for engineers to understand movements and loads imposed on the structure in order to predict potential problems and to maximise the safe working life of the bridge. Ageing bridge structures may be reaching overload due to the effects of increased weights and traffic volumes on steel structures that may be also weakened by corrosion or suffering early metal fatigue.

Very often the transducers used to monitor movements are installed on structures in coastal regions where the rain water must be considered saline and transducers are also exposed to chemical pollutants created by road vehicles. RDP Electronics Ltd offers many different types of products with a very high water ingress protection rating. Transducers can be supplied that are moisture resistant or fully welded for submersible applications. Thanks to a stainless steel construction these transducers are suited to operation in marine environments and also resist the corrosive effects due to winter road treatments for ice.

The LVDT monitoring approach is relatively inexpensive particularly when several points on a bridge need to be monitored, calling for long cable runs. By using a 4-20mA 2 wire loop, the wiring installation cost can be considerably reduced, as well as this offering the best interface to use with long cables for temperature drift reasons.

Reducing stress!

Westermo industrial Ethernet switch reduces the stress for ABB Force Measurement

ABB FM (Force Measurement) is using Westermo’s Redfox industrial Ethernet switch with its latest version of Stressometer system for measurement and control of rolling mills. The implementation of the Redfox Industrial device has helped to reduce the number of data communication products needed from six to one, simplifying the system and lowering costs.

ABB FM is a leading global supplier of control systems for rolling mills. The company’s Stressometer system, consisting of a variety of measuring and control instruments, optimises the process to produce the highest quality rolled products. When implementing a previous version of the Stressometer system, the rolling mill control network would often consist of up to six different networking devices. These included switches, routers, converters and firewalls that would invariably be supplied by different manufacturers. This could result in compatibility issues and a lack of critical networking functions such as secure VPNs and separation of networks. It also resulted in difficulties installing and maintaining these complex networks. The greater number of products needing to be configured meant it took longer to install and required a higher level of network knowledge. The need to use multiple products also contributed to a congested control cabinet, which would then need to be cooled. This leads to increased maintenance requirements as fans become worn.

The networking solution for Stressometer is now based on a single RedFox Industrial 18 port, layer 3 switch running Westermo’s WeOS operating system. The WeOS operating system has been developed to provide layer 2 and layer 3 functions, which means the RedFox Industrial device can be used as both a switch and a router. The WeOS operating system can also manage complex networking issues including advanced security. For example each port can be configured with individual firewall rules and support is provided for encrypted VPN tunnels, which means you can connect securely over the internet. These new functions provided by Redfox Industrial Are now enabling the Stressometer system to handle multiple data communication networks within the mill using a single networking device.

"We have been delivering this latest version of the Stressometer system incorporating the RedFox Industrial device since 2010 and we have had no problems at all with the data communications," says Christer Gustafsson, Data Communications Manager at ABB FM. "When we upgraded our system we wanted a more unified networking solution. The Westermo device helps achieve this by avoiding compatibility problems between products from different manufacturers. Because of this the system is now easier for us to install and maintain and costs less to deliver.”

The RedFox Industrial’s WeOS operating system enables the communication network to be subdivided into three Virtual VLANs: A protected VLAN, using an encrypted VPN tunnel that is not accessible by the client, connects all the measuring and control instruments. A second VLAN connects to the rolling mill control computer and the third connects to the mill's office network. This provides a link to the Internet and enables the system to be monitored securely from outside the industrial network.

The new network solution for the Stressometer system is delivered preconfigured and installation is as simple as plugging in a few cables. Once in place, it is virtually maintenance free. If the Stressometer system requires updates or servicing, ABB FM can simply access the protected part of the network over the Internet via the encrypted VPN tunnel. Although the system is pre-configured it is still very flexible. Should equipment be plugged in or moved Network Address Translation (NAT) rules can be applied without affecting the original configuration.

The ABB Stressometer systems are installed in tough industrial environments. Westermo’s RedFox Industrial switch has been designed specifically for such applications and will operate in environments with high levels of electromagnetic interference and in extreme temperatures of between -40 to +70degC.

"We have tried many different industrial data communication products from different suppliers, but none have been good enough for our demanding requirements. The new solution, incorporating the Westermo device, works very well and requires very little technical support," concludes Gustafsson.

Preventing deadly accidents

Systems from VPG Transducers help prevent deadly construction and heavy equipment accidents

VPG Transducers is working with heavy equipment manufacturers to create highly accurate and reliable systems that dynamically measure stresses in key vehicle components caused by such factors as overloading, vehicle tilt, and high winds.

Deadly and costly accidents occur each year worldwide involving cranes, telescopic handlers, and forklift equipment. Many of these accidents are the result of improper loading of the vehicle, driving on uneven or sloped surfaces, or environmental factors such as high winds. Now industry-leading companies who manufacture heavy lifting and construction equipment are turning to VPG Transducers for custom force-sensing solutions that help alert the driver when unsafe operating conditions exist on the vehicle.

VPG Transducers has partnered with equipment manufacturers to develop load moment indicators (LMIs), which are integrated into the vehicle design assembly, to dynamically measure the forces imparted on key components of the vehicle such as the rear axle. The signal from a VPG Transducers force sensor is sent to the LMI, which calculates and displays the current load seen on the vehicle and sets off an alarm if the vehicle is operating at an unsafe level. These levels are set in close coordination with the vehicle manufacturer. This system is also applicable for crane applications as well.

The sensors and LMI system are designed and manufactured by VPG Transducers to survive in the harshest of environments and have exceptional reliability and longevity, which are very important factors for equipment used in the agricultural industry.

The effect of girth tension on horse gait!

Ireland is famous for its livestock and the quality of its horses. This is an interesting application for the equine industry which is so important to both Ireland, Britain and throughout the world.

Using electrical systems for the measurement of mechanical forces is by no means limited to machines and laboratory based applications. In her recently completed research thesis ‘Girth Tensions and their Effects on Equine Stride Characteristics’, Sue Wright of Moulton College Northampton (GB) used load cells, motion sensors and GPS amongst other technologies to measure and record the tension within the girth strap used to hold the saddle in place.

The aim of the investigation was to determine if girth tension affects equine stride characteristics. The positioning and tightening of the girth strap has traditionally been based on the rider’s preference or own training, in the knowledge that too loose or too tight would be dangerous to both rider and horse.

It is well known that optimum girth tension varies between the size and type of horse, the activity –racing etc and the type of girth. However there is little if any published information on girth tension and how this may affect the locomotion of the horse, that is duration, stride length and speed.

A custom designed S-type tension load cell was used to continuously monitor the tension in the girth during the period under test. The load cell was mounted almost vertically alongside the chest of the horse where unwanted torsional effects on the load cell would be at their minimum, it was fitted to the strap via rod-end bearings and a cam buckle so that minute changes to the girth tension could be made.
This was connected to a T24 telemetry module, located in a pouch on top of the saddle which transmitted the force reading wirelessly to a telemetry base station located nearby. This was plugged into a laptop that served to both power it and log the tension reading.

Extensive testing on 19 horses at 4 girth tension settings were conducted resulting in definite conclusions on the effect of girth tension on the speed, stride length, stride duration and walk.

This application is typical of the way in which Applied Measurements’ custom force sensors are helping all sectors of research and development as well as solving the needs of industrial production.

New stress analysis service

Having built their first transducer in 1991, Applied Measurements of Reading (GB) now offer an ISO 9001 compliant stress analysis service to complement existing in-house manufacturing of strain gauge based sensors for the measurement of load, force, pressure, torque and linear displacement.

Increasingly measurements are required on parts that either cannot be moved or the application is for research and long term monitoring is required. This might include bonding of strain gauges directly to components, structures or machines.  The service can be tuned to suit specific customer requirements that may include installation and calibration only, design of bespoke transducers to run a test or full installation, testing and reporting on completion.

Applied Measurements can accommodate all measurement parameters including short as well as long term tests, harsh or potentially explosive environments, multiple measurement channels and extremes of temperatures. These include both fixed and rotating applications where wireless signal transmission may be required.

Typical applications include:

• Torque measurement on drives & PTO’s
• Static tests such as structural monitoring with remote data acquisition
• Fatigue tests for life estimations & equipment failure investigation
• Gravimetric level control of silos and hoppers
• Press force monitoring
• Residual stress analysis and crack propagation
• Custom sensors for automotive, marine, aerospace etc

Applied Measurements’ field service team travel throughout Britain and overseas and there are few applications the team haven’t seen before. “We are already highly experienced in the supply of sensors into industries as diverse as medical, marine and motor racing. We understand the needs of bespoke applications and what it takes to get reliable measurements in conditions that are often less than ideal,” stated David Johnson, Head of Business Development.

As Senior Structural Engineer Adrian Robinson at Wright Group says about the service supplied, “we find them to be very flexible and reliable in meeting our demanding needs. We would have no hesitation in recommending them to other companies”
And Airbus UK Launch Manager endorses these services further by saying “they have supported every aspect required of this program in a prompt, efficient and innovative manner whilst playing an integral part in supporting the most successful FTI program in Airbus UK’s history”

The British Society of Strain Measurement (BSSM) underpins installation standards, as the quality of the strain gauge application is vital to reliable long-term measurements. “As one of the most experienced manufacturers of strain gauge transducers in the country, we are grateful for this opportunity to partner Sensor Solutions Ltd - specialists in this type of work, as it is integral to the expansion of our skills base and adds to our continuing success. Additionally, launching of this service coincides with the increased traffic being seen amongst insightful engineering organisations for a service to qualify the actual performance of equipment against predicted, as well as audit of aging plant,” concluded Johnson.

Load cell for structural and fatigue testing applications

LCM Systems have just announced the new PTC-1 range of low profile, universal load cells. Ideal for many testing applications including structural and airframe testing, Jack Load monitoring and material and fatigue test machine feedback, this new series has been designed for use where high stability and low height are essential requirements.

These load cells are available with a rated load from 5 to 1000kN and offer high natural frequency, low deflection and excellent resistance to side and torsion forces thanks to the shear web internal construction. The stainless steel construction ensures corrosion protection both for the load cells themselves and the optional mounting base, which is necessary if the load cells are to be used in tension.

For use in a wide range of harsh and rugged environments, the PTC-1 load cells are supplied with both an integral MIL-SPEC connector and a mating connector. The cells are also sealed to IP66.

The cells can be supplied calibrated and the in-house technical department at LCM Systems can advise and provide a comprehensive range of load cell instrumentation for ‘ready to go’ systems.