Clifford Spring Co. developed an energy absorbing spring for the oil and gas industry that is non corrosive, chemical resistant, with high and low temperature resistance. The company selected a Vitrex Peek to develop the spring.

Victrex Peek (polyaryletherketone) polymers is said to be a good choice when replacing metal wind-turbine components. The high performance and light-weight material allows up to a 70% weight reduction. This can lower stress on the components and reduce energy needed to power the turbine. The tribological characteristics of this thermoplastic compared to metals also helps reduce downtime due to the inherent ability to perform with or without lubrication.

The polymers are useful in wind turbine applications such as bearing separators, connectors, braking systems, and pitches and yaw drive components. The material can be applied to wind equipment to create products that are more corrosion and high temperature resistant, light-weight, durable and stable. Most notably, wind turbine products benefit from PEEK’s strength and wear properties. Victrex polymers also prevent galvanic corrosion, and are an exceptional insulator for generators, motors or transformers. The polymers help extend equipment life, reduce product failures, improve thermal performance and material strength.

Victrex Corp.
Victrex.com

Windpower Engineering & Development

-NSK

Machines that manufacture advanced wind turbines and towers depend a lot on conventional yet also advanced manufacturing methods, such as welding. One welding-machine manufacturer recently called on a linear motion and assembly-technology company to help improve custom welding machines for the wind industry. Such welding equipment is used to build turbine towers up to 100-m high.

Typically, a machine rolls a metal plate, often 709 grade 50 carbon steel. into a cylinder called a “can” that measures about 9-ft long by 8 to 15-ft dia. Another machine then welds along longitudinal seams to complete the can and then circumferentially to join them with multi-pass butt welds made by submerged arc welding.

The weld head is suspended from a cantilevered guide rail for outside welding. Most of the machine is stationary while the weld head moves short distances on two and three axes, both along and across a seam. A linear control actuator at the end of a horizontal arm determines the motion of the weld head. Smaller can sections are welded on a large assembly line, called a growing line.

Welding procedures and consumables can vary based on tower requirements for height, design, and location.

After assembling the sections and adding internal tower equipment, such as ladders, they are transported to the installation site, lifted into place, and bolted together.

Welding requirements for offshore tower construction are impacted by the tower’s large size and associated nacelles, as well as the thicker steel required for strength and fatigue resistance. Joining thicker steel sections with larger weld joints requires using a greater volume of welding consumables, thus requiring additional welding passes. This adds time and cost to the job.

Fabricating towers capable of resisting extreme environmental conditions requires thicker plate, or higher-strength steel, or both along with higherstrength weld deposits. Welding such material requires welding procedures and filler metal with a chemical composition that delivers the same mechanical properties in the weld deposit.

Using consumables intended for offshore towers minimizes the associated welding problems, such as cracking. Submerged arc-welding flux and electrodes have been developed to provide the strength and impact properties required for onshore and offshore towers, including the more rigorous requirements of coldclimate towers.

A recent welder is said to give operators the flexibility to control every aspect of the welding output to provide the best results for an application. Enhanced control over the welding waveform let operators weld at significantly higher deposition rates than comparable conventional power sources, thereby improving weld productivity and reducing costs. In addition, multiple power sources can be used to weld with multiple arcs to increase deposition rates and reduce the number of passes required to fill the joint. This decreases production time and consumables, contributing to lower overall wind project costs.

Windpower Engineering & Development

Portable circular mill. -Climax Portable Machine Tools

The portable circular milling machine is said to expedite on-site machining of large flanges from 73.5 to 199-in. diameter. The manufacturer says the mill is capable of extremely tight flatness tolerances required for wind-tower flanges as well as a surface finish of 63Ra (1.6Rm). The circular mill can be configured for milling or single-point machining as well as grinding operations.

Circular mills also are used on assembly lines in wind-tower fabrications and in-field services to machine flanges to spec that may have warped in welding. Multiple mounting options are another feature. It includes ID/ OD or face-mounted configurations, and a tubular rigid chucking system with adjustable feet. These allow leveling the machine quickly and precisely in the flange for simple and speedy setup.

A special compact gear hobber may let shops generate splines, spur, or helical gears in one operation. An adjustable tool holder eliminates having to transfer rough gears on one machine to another for gear hobbing. To compensate for different types of grooves or pitches in splines and gears, users simply set a vernier dial to ± 20°. The machine’s a compact design lets it operate in most instances without interrupting neighboring tool stations.

The gear-driven gear hobber is built for heavy machining loads and delivers 45 Nm torque and speeds to 3,000 rpm for hobs or slotting saws up to 2.480-in. dia (63 mm).

Arbor diameters are available for all standard sizes for use of slotting saws and gear hobs. Changing tools takes just seconds by removing the yoke plate and sliding out the arbor. The base of the tool holder remains in its station.

Abrasive water jets, the third item in this short list, can cut a wide variety of materials, including composites (turbine blades) and metals such as aluminum, stainless and mild steel, and titanium with an accuracy of motion up to ± 0.003 inches (0.076 mm). A cutting head that tilts on one waterjet cutting machine is said to make a cost-efficient, productive jet-cutting center with a multi-axis accessory and a direct-drive pump.

Manufacturers say abrasives waterjets are well suited for precision machining of larger or multiple parts. One manufacturer says it product is equipped with a drive system, developed for abrasive waterjet machining to ensure high accuracy. The drive is enclosed inside coated steel covers, making it well suited for harsh environments and requiring little maintenance. A recent design allows faster traverse speeds than traditional drive systems that reduce processing times when machining multiple or nested parts.

Windpower Engineering & Development

The closed-mold doctors will be "in" at the COMPOSITES 2012 show in Vegas. 15 partners to demo different tech and materials for a range of products.

Composites One, along with the Closed Mold Alliance and over 15 industry partners, will host  comprehensive, ongoing demonstrations of closed-mold technology –on the show floor – during COMPOSITES 2012 in Las Vegas, Nevada. Presentations will take place in a specially designed staging area at Booth #629, Wednesday, February 22, and Thursday, February 23.

At the event, manufacturers can experience work cells demonstrating closed-mold processes such as Light Resin Transfer Molding (Light RTM), the Vacuum Infusion Process (VIP), and Flex Molding to produce replica wind-turbine blades, a half hull, and a mini boat hull. Highlighting this year’s event will be the latest technologies that enhance closed-mold production.

New this year will be the introduction of a specially formulated CCP Composites OptiPLUS infusion resin for tooling to the Vacuum Infusion Process. Vacuum Infusion, ideal for making large and small part tooling, has benefits traditional tool manufacturing does not.

“The importance of a quality manufacturing process is key to successful tooling,” says Composites One VP Greg Shymske. “With infused tooling, manufacturers find improved heat resistance, extended mold life, faster build times, as well as a significant reduction in styrene emissions.”

Also featured this year will be Flex Molding Technology, developed by Magnum Venus Plastech, and improved upon by the Closed Mold Alliance. The program will feature a video demo of how to make a silicone bag using the Flex Mold Process. Afterward, a live demo using the same silicone bag will feature production of a replica wind blade. In addition, new Flex Molding Controls will be featured in all work cells during the two-day demonstration.

This year, the Lean Mean Closed Mold Machine will feature demonstrations of advanced composite technologies, including Axiom Prepreg, Huntsman Epoxies, MIT Recycled Carbon Fiber Preforms, and Bayer Polyurethane Resin Systems. These presentations will showcase a number of different parts including a tractor hood and a motorcycle engine cover.

“We recognize the importance that emerging technologies have to composites manufacturers today,” says Shymske.  “And by including products that offer high performance properties, no styrene emissions, and environmentally-friendly features, we will demonstrate that these products have a place in many composites markets, as well as being a perfect complement to closed mold processes.“

New to the demonstrations this year will be the launch of the Sprayomer technology by SR Composites.  This flexible bag system is well suited for a variety of parts. The demonstration will also showcase the CARTM process and benefits it offers to those manufacturers using closed molding today.

The Lean Mean Closed Mold Machine at COMPOSITES 2012 will also showcase a micro-infused resin technology that can be used in closed molding. MIRteq is a highly versatile material in so far as it is viscous at room temperature and can be poured, pumped, sprayed and machined to deliver a wide range of engineering solutions.  Access to the technology is available exclusively through Composites One.

All closed mold demonstrations will feature Magnum Venus Plastech (MVP), the industry’s leading meter/mix equipment manufacturer with specific expertise in closed mold processes and a member of the Closed Mold Alliance.  The program will also be presented with the assistance of Alliance member RTM North Technologies, North America’s leading Light RTM experts. Composites One is a member of the Closed Mold Alliance. Throughout the event, industry experts from the Alliance, along with the Composites One Closed Mold Team, will be on hand to answer questions about closed-mold processes, discuss equipment and materials, and help manufacturers learn how to put closed mold to work in their operation.

The live demos at COMPOSITES 2012 are the culmination of a joint effort between Composites One, the Closed Mold Alliance and its supplier partners: Airtech Advanced Materials Group, Airex Baltek, Arkema, Axiom, Bayer Material Science, CCP Composites, Chemtrend, Chomarat, Huntsman Advanced Materials, ITW Plexus, JRL/Marine Composites, Kit Concepts, Magnum Venus Plastech, MIRteq, MIT, Owens Corning, RTM North Technologies, RTM North Solutions,  Sprayomer, Syrgis, Vectorply, and Wacker Silicones.

“Composites One and the Closed Mold Alliance is the one place where manufacturers can find leading industry closed mold experts who can offer them a roadmap to successful closed mold conversion,” says Shymske.

Composites One
www.compositesone.com

Closed Mold Alliance
www.closedmoldalliance.com

Windpower Engineering & Development

The main toolbar of GL Bladed gives users access to data entry screens which allows defining various turbine components.

Software called Bladed provides wind turbine and component manufacturers, certification agencies, design consultants, and research organizations a design tool that has been extensively validated against measured data from a wide range of turbines. The developer says the software is the industry standard for the design and certification of onshore and offshore turbines. It lets users conduct the full range of performance and loading calculations. Based on Windows, it supports calculations of combined wind and wave loading, with full aeroelastic and hydroelastic modeling. It has been validated by Germanischer Lloyd for the calculation of wind-turbine loads for design and certification.

Bladed uses a self-consistent and rigorous formulation of structural dynamics. This provides consistently reliable and accurate results, and forms a solid foundation from which to continue to extend the structural model with features as part of the ongoing development program.

The software has several specialist bolt-on modules covering steady state analysis, dynamic-load simulations, analysis of loads and energy capture, batch processing and automated report generation, interaction with the electrical network, and model linearization for control design.

The developer says the software is the industry standard for the design and certification of onshore and offshore turbines. It provides a design tool extensively validated against measured data from a wide range of turbines and lets them conduct a range of performance and loading calculations. Bladed offers a Windows-based interface and supports calculations of combined wind and wave loading, with full aeroelastic and hydroelastic modeling. It has been validated by Germanischer Lloyd for the calculation of wind turbine loads for design and certification. GL Garrad Hassan’s approach to the calculation of wind turbine performance and loading has been constantly evolving since 1984 . The corresponding ongoing software development has maintained GL Garrad Hassan’s reputation for delivering reliable tools for use in the design and certification of wind turbines.

Bladed software includes comprehensive models of complex wind fields which can excite the turbine.

Bladed V4 uses a new, completely self-consistent, and rigorous formulation of the structural dynamics. This provides consistently reliable and accurate results, and forms a solid foundation from which to extend the structural model with many new features in the ongoing development program. New features for Bladed V4 include:

• Modeling of Individual blade modes, valid for pitch angle
• Allowance for non-symmetrical rotor
• Fully coupled flapwise, edgewise, and torsional degrees of freedom in three-dimensional blade modes
• Advanced definition options for blade geometry and structure
• Torsional degree of freedom modeling for all tower types

Bladed is used by wind turbine and component manufacturers, certification agencies, design consultants and research organizations across the world. An educational version provides a world class tool for teaching wind turbine technology.

GL Garrad Hassan
www.gl-garradhassan.com

Windpower Engineering & Development

The green material indicates where Masterflow 9500 could be used in wind turbine towers.

“This ultra-high strength grout demonstrates pioneering properties and will be a welcome addition to the range of specialized grouts we mix and pump for clients,” said Jim Bell, Managing Director for FoundOcean.

The grout has been tested and validated by licensing bodies for use in grouted connections of offshore foundations, and is the only product that comes with a detailed and grout specific ‘Statement of Compliance’ by DNV.

This ‘fit for purpose’ grout demonstrates good properties such as low heat of hydration thus eliminating the risk of thermal cracking, rapid strength build-up even at low temperatures to support increased installation rates and 28 day compressive strengths of 140 MPa,” says Charles Elins, BASF Regional Projects Manager UK and Ireland.

In addition, Masterflow 9500 can be pumped at temperatures as low as 0ºC which means the available installation season can be extended and offshore wind farms can be operational sooner. Lastly, the grout is said to exhibit zero autogenous shrinkage, a factor which when significant enough is proven to cause cracking in high-strength concrete structures.

BASF
www.windfarmfoundations.co.uk

Windpower Engineering & Development

VABS V3.6 provides optimized meshes for FEA work especially on thin structure such as wind turbine rotor blades.

A provider of efficient high-fidelity modeling software for aerospace, energy composites, and other advanced materials has released VABS 3.6. The developer says the software is the tool of choice for efficient and accurate modeling of composite slender structures such as wind-turbine blades, helicopter rotor blades, high-aspect ratio wings, composite bridges, and other slender structural components.

The main feature of VABS 3.6 is an improved method of optimizing the finite-element mesh.  V3.6 is several times faster than the previous version for large problems. The slower I/O (Input/Output) performance reported by some users was corrected. Furthermore, V3.6 can handle larger models, which cannot be analyzed by previous versions.

“For a realistic blade meshed with 200,000 degrees of freedom (DOFs), using a typical laptop, VABS 3.6 takes less than 20 seconds for constitutive modeling (Timoshenko model), while VABS 3.5 takes about 4 min. for constitutive modeling,” says AnalySwift CTO Dr. Wenbin Yu. “Of course, if one uses Dynamic Link Libraries, it will be even faster because a significant portion of time for large problems is spend by I/O with hard drives.”

“While VABS is already known for its efficiency in realistic multiphysics blade modeling, this version is even more appealing by taking it to the next level,” says AnalySwift President Allan Wood. Yu adds that VABS is the only tool capable of rigorously modeling 3D slender solids with complex buildup structures, such as composite wind-turbine blades. The efficient high-fidelity tools offered through AnalySwift let companies bring products to market more quickly and at a lower cost with the best available compromise of accuracy, efficiency, and versatility.

The technology in VABS is said to make it the first efficient high-fidelity modeling tool for composite beams, saving users many orders of magnitude in computing time relative to more complex and time-consuming 3D finite-element analyses, without a loss of accuracy. Engineers can now confidently design and analyze real structures with complex internal construction due to this unique efficient high-fidelity feature.  For instance, structures as complex as real composite rotor blades with hundreds of layers are easily handled by a laptop computer.

AnalySwift LLC
www.AnalySwif

Windpower Engineering & Development

The company says it is making the move in response to the growing demand of a low-cost carbon fiber prepreg supply in wind energy and other applications. “Our strategy has been to commercialize carbon fiber and broaden its use in industrial applications through low-cost and supply availability”, says CEO Zsolt Rumy. “Unfortunately, the current carbon fiber prepreg supply is fragmented and geared towards aerospace markets rather than industrial use. We are addressing this shortfall by consolidating the supply chain and forward integrating into prepreg manufacturing for select industrial applications.”

St. Louis is home to Zoltek’s headquarters and one of their four carbon fiber manufacturing facilities. The new location will also serve as a technical center for carbon-fiber applications, specifically targeting wind energy and automotive applications.

Wind energy is a leading application for Zoltek’s prepreg carbon fiber due to its unique and inherent characteristics (high-stiffness, high-strength, lightweight). Recent trends in wind energy have spurred wind-blade manufactures to create longer turbine blades. Carbon-fiber composites have proven ideal for wind blade turbine reinforcement, letting longer blades capture more wind energy, even at lower wind speeds.

Automotive is a growing application for carbon fibers, where the strength-to-weight ratio of carbon fibers enables vehicles to be lighter weight and therefore more fuel-efficient. Other applications include offshore drilling, infrastructure repair, marine, and other applications requiring a high strength and light-weight material.

In addition to the two production facilities in St. Louis, Zoltek has carbon fiber manufacturing facilities in Hungary, Mexico, and Texas.

Zoltek Corp.
www.zoltek.com

Windpower Engineering & Development

Until recently, copper has been the predominant material in wire and cable used to grounding of electrical systems. But the cost of copper fluctuates substantially. This is bad news for windfarm developers, and electrical and construction contractors who are under increasing pressure to control costs.

For instance, there are several solutions to the climbing cost of all copper. One for wire is in copper-clad steel. It is said to be reliable, cost effective, and can provide the wind industry with a smarter alternative to copper-based grounding systems. With respect to electrical conductors, aluminum in wires is also substituting for copper as its cost climbs.

The financial crisis has altered the trajectory of wind-farm projects by tightening developers’ budgets with a need to control costs, an increasing priority even as the industry expands.

Given the cost sensitivity of any wind project, the idea of burying a precious metal (copper) underground makes little economic sense when less expensive, alternatives are readily available. Copper-clad steel has been around for decades and is a practical option to consider in grounding applications. It offers an alternative to copper by combining the strength of steel with the conductivity of copper through a cladding that delivers comparable performance.

Windpower Engineering & Development

Rare earths: The neodymium used in permanent magnets deserves attention. The rare earth and others have been supplied from mines in China but that country has restricted their exports, driving up generator costs. As a result, other sources of rare earth materials will enter world supply in the next year or two, which should keep material costs on the recent downward trend.

Metals: The most used metal in a wind turbine is steel in the tower and other components. But a few more recent material formulations deserve mention. For instance, one solution to the climbing cost of all copper wire is in copperclad steel. It is said to be reliable, cost effective, and can provide the wind industry with a smarter alternative to copper-based grounding systems.

A good grounding system plays a critical role guarding against catastrophic damage to blades, electronics, transformers, nacelles, and collector systems out to substations.

Until recently, copper has been the predominant material in wire and cable used to ground of electrical systems. But the cost of copper fluctuates substantially. This is bad news for wind-farm developers, and electrical and construction contractors under increasing pressure to control costs.

Given the cost sensitivity of any wind-farm project, the idea of burying a precious metal (copper) underground makes little economic sense when less expensive alternatives are readily available. Copper-clad steel has been around for decades and is a practical option to consider in grounding applications. It offers an alternative to copper by combining the strength of steel with the conductivity of copper through a cladding that delivers comparable performance.

Polymer adhesives: Because of a large spectrum of possible polymer architectures, polyurethane adhesives have been used as bonding agents in many different industrial sectors for more than 30 years. Construction, automotive, transportation, and shipping vessels have all benefited from the use of polyurethanes.

A recent polyurethane (PUR) adhesive satisfies particular mechanical requirements for use in the wind industry while improving the long-term reliability of rotor blades. It also makes rotor-blade production faster and less expensive. The adhesive is said to provide superior dynamic fatigue strength and increased resistance to crack propagation, while making the production of rotor blades more efficient than with epoxy technology. For instance, says the supplier, the PUR adhesive requires fewer curing steps than epoxies, resulting in reduced production costs and production cycles 15 to 30% shorter.

In addition to blade bonding, the two-component polyurethane adhesive is also used in other structural bonding applications on turbines including bonding components to the rotor blade, performing field repairs of blades, and securing various components inside the tower assembly.

GL’s requirements for the adhesive primarily relate to its tensile-shear strength, long-term durability, creep behavior, and glass transition. The adhesive’s physical properties are temperature-dependent. Within a temperature range known as glass transition (Tg), the change in the adhesive’s mechanical properties is considerable. The glass-transition temperature separates the lower, brittle, or glass range from the upper, flexible, or rubbery-elastic range.

Windpower Engineering & Development