MSC Software Corporation

Welding is a common practice in the automotive, aerospace, railways, ship building, and machinery industries. It allows for the joining of components by subjecting them to intense localized heat which melts and coalesces the material in the welded region, forming a permanent joint. Multiple process parameters influence the effectiveness of the welding, which include energy source, shape and size of the melt zone, heat affected zone, and speed. Understanding and improving this challenging process through physical iteration can be time consuming and expensive. MSC’s Marc, a nonlinear finite element analysis tool, can provide the required insights needed to solve these parameters in a cost-effective manner.

The model demonstrated the effects of thermal contact at the joint interface during GTAW welding of the dissimilar materials, and the influence of transverse offsetting of the arc away from the weld line. “We found Marc to be very good in simulating the complex physics of the welding problems. Matching results with experimental data demonstrated that this approach can be used to significant costs by reducing material waste and improving life of the welded parts,” says Singh.

• Easily try alternative approaches without having to invest in physical experimentation
• Gain greater insight into temperature gradients with simulation, which are harder to measure in physical tests

Mankind has explored the galaxies, the depths of the sea, and looked back millions of years into the past. But, there are still some surprisingly large gaps in our understanding of the human body and how it works. For example, the knee joint is at the center of the kinetic chain running from the foot to the pelvis. But the connection between the tibia and femur provides very little geometric constraint. Knee stability is achieved through the operation of a multitude of soft tissue structures. The details of how these structures work are still largely a mystery. MSC’s Adams, a multibody dynamics simulation solution, can provide the right insights to help get a better understanding of the inner workings of the knee.

With the use of Adams, MAC researchers have begun to take the steps to grasp the complexity of the menisci function in the knee. They found that increasing the ligament length by about 20% will result in almost a complete loss of force transfer through the menisci during walking. The reduction in the forces absorbed by the menisci increases the forces that were directly transmitted between the tibia and femur, increasing the potential for joint damage and pain. These results will enable researchers and physicians to target and prevent future pain and damage more efficiently than ever before.

• Predicts ground reaction forces with over 90% correlation to physical results
• Accurately predicts internal contact forces
• Determines effect of slack in menisci

There are many coastal areas where local geography constrains the movement of ocean tides, resulting in very strong currents. Water is 800 times denser than air so these currents could potentially generate a lot of electricity. GE tidal turbine technology brings proven concepts and industry-leading knowledge to tap into this reliable and predictable energy source. The Oceade* tidal turbine features a buoyant nacelle that enables the turbine to be easily towed to and from the operating site. This eliminates the need for specialist vessels, reducing the cost of installation and maintenance. GE has proven its Oceade* turbine operating at a full 1 Megawatt, injecting over 1.2 GWh of electricity to the grid. This test program has enabled GE to validate the installation and retrieval processes, autonomous running, and the performance and power curve of the new turbine.

The simulation results provided the information to evaluate the dynamic response of the proposed design prior to investing in a physical prototype and testing. Based on the results, GE design assumptions and margins were verified and opportunities for optimization identified. The company is now moving forward to the testing phase confident that the design has been “de-risked” from a dynamic as well as a kinematic standpoint. “This project was a great working experience that allowed the GE team and MSC consultants to share knowledge and gain experience from their own respective expertise,” concluded Valentin Radigois, Lead Engineer, Mechanical- Components, GE Renewable Energy.

• Predict the dynamic behavior of the turbine including multiple flexible components
• Integrate real bearing and gear effect including 3D contacts
• Simulate various dynamic loads to evaluate complex behaviors and coupling effects
• Performed modal analysis of the full structure

Stamping operations used to form metallic automotive components can generate forces of thousands of tons. The tools (die components) that form these products must be able to withstand this cyclic loading environment for the life of the vehicle program. At the same time, it is important to optimize the tool design in order to be competitive. The evolution of higher strength materials also adds to the challenge. The large loads involved in forming these components increase the challenge of designing robust tools. Both linear and non-linear analysis must be used to support the tool design process.

“In order to get reliable predictions, we prefer to use the nonlinear software Marc to solve these types of problems because it accounts for the inherent nonlinearities of materials experiencing plastic strain,” said Yueming Cheng, Computer Aided Engineering Engineer at Tower International. “In years of using Marc and Mentat, I have found it to be capable of accurately simulating a wide range of nonlinear product behavior under static, dynamic and multi-physics loading scenarios. Marc is also one of the commercial solutions in markets I am aware of that has robust manufacturing simulation capabilities, with the ability to predict general damage, failure and crack propagation.”

• Accurate simulations help reduce risk of downtime and lost revenues, by predicting regions of potential failure
• Get the design right the first time with computer models and deliver reliable performance

Shanghai Jiao Tong University researchers including Dr. Gao Feng, Director of the Chinese National Laboratory of Mechanical System and Vibration at SJTU and Dr. Yang Pan, Postdoctoral Research Fellow at SJTU, have designed the Octopus III six-legged robot for moving, searching, detecting, repairing and rescuing in extreme environments such as nuclear radiation, fires, and underwater. The six-legged Octopus III robot takes advantage of the unusual capabilities of legged robots such as traversing uneven terrain, overcoming obstacles, performing vertical climbs, and righting themselves after turning over.

Legged robots are substantially more difficult to design than wheeled robots because they require complex mechanics and control strategies to maintain their equilibrium, orientation, efficiency and speed. The Octopus III’s six legs each have an identical drive mechanism consisting a parallel mechanism with three limbs. Each leg has one UP limb with a universal joint and a prismatic joint connected in series and two UPS limbs with a universal joint, a prismatic joint and spherical joint connected in series.

The robot is controlled by an onboard computer running the Linux operating system that communicates wirelessly with a remote computer running the Windows operating system. Orders such as move forward or turn left can be issued to the robot through a human machine interface (HMI) on the Windows computer. The onboard computer contains optimized kinematics and dynamic models of the robot and controls the robot’s 180 servo motors. The robot weighs about 270 kg, can climb a 20 degree slope and walks at 1.08 km/hr.

The SJTU researchers tested the prototype under a wide range of conditions such as turning valves and switches and carrying loads of up to 500 kilograms in order to evaluate its fitness for proposed missions. The physical experiments showed that the performance of the prototype closely matched the Adams predictions. “If we had not used Adams to optimize the design prior to building the prototype, we would probably have needed five additional prototypes at a cost of $100,000 each to get the design right,” Pan said. “With Adams, the first prototype worked exactly as intended so we did not have to make a single change.”

• The Adams/View command language works well for parametric modeling of robots
• The performance of the prototype closely matched the Adams predictions
• Applying Adams simulation early in their robot design saved five additional prototypes at a cost of $100,000 each

Auburn University fielded a senior design team working to compete in the 2016 AFRL University Design Challenge. The senior design team designed and constructed the TRIAD (Tactical Rope Insertion Assist Device) to assist soldiers in a rapid decent. During the design process, Adams was utilized to model the flexible rope and the TRIAD and simulate how the device would perform. The flexible rope was modelled using beam elements with material properties that replicated the behavior of the actual Nylon rope used in practice. An image of one of these simulations is provided in Figure 1. The weight of the person using the device is represented by the addition of the weight highlighted in green. Scripts were developed in the form of command files that would enable an Adams user to enter a variety of parameters for the rope for quick model building and further simulations. These simulations revealed some problems in the preliminary designs that were also seen in testing, and these problems were subsequently addressed for the final design and competition prototype.

Auburn University worked in developing user written subroutines and an Adams plugin that would predict the wear rates of objects rattling inside of an enclosure. An example of this includes a projectile with attached shoe (Figure 2), that can slide out from the enclosure upon release. During transport the projectile could rattle causing wear of the enclosure. An experimental wear study was performed to determine wear coefficients, which were employed in an Adams simulation to determine contact forces, contact area, wear rate and total wear over time.

We have worked with them on undergraduate capstone design projects and graduate student research projects, where we design and build a physical prototype, run experiments and performance studies on those, and virtual prototype in Adams.
David Beale, Professor, ME

The traditional approach for suppliers to the automobile industry has been to build parts according to drawings provided by original equipment manufacturers (OEMs). Today, OEMs are delegating much more of the design responsibility to suppliers. This trend significantly changes the role of suppliers who, instead of competing primarily on quality, price and delivery time, are now often judged based on their ability to develop an innovative design that can meet the OEM’s requirements and be produced at a high level of quality and a low cost.

As a leading supplier of gaskets to the automotive industry and other markets, Interseals responded to these trends by increasing the size and capabilities of its engineering team. Yet, in the past, the company still faced difficulties in meeting its customers’ requests for innovative and economical designs. Gaskets are difficult to design because rubber components can undergo large deformations under load, sustaining strains of up to 500% in engineering applications. The load-extension behavior of rubber is extremely nonlinear and time and temperature dependent. Previously, when Interseals engineers based their initial designs on experience and handbook formulas, they usually found that the initial prototype did not meet the customer’s requirements. Typically, it took two more iterations to get the design right. Each design iteration cost an average of 5,000 Euros in tooling expenses and took between six and eight weeks.

Interseals engineers shared the simulation results with the customer and the customer gave the go-ahead to build the mold. When the mold was completed, Interseals made a number of prototypes and provided them to the customer. “The customer tested the prototypes and said that they met every requirement,” Izzo said. “Getting the design right the first time saved an estimated 10,000 Euros in additional tooling costs and made it possible to deliver the gaskets 16 weeks earlier than if 2 additional prototype iterations had been required as was normal with our previous design methods.”

• Marc has been capable of predicting the complex nonlinear behavior, while taking into account time and temperature effects and calculate compressible and incompressible material models based on test data.
• Using simulation allowed the customer to save an estimated 10,000 Euros in additional tooling costs and made it possible to deliver the gaskets 16 weeks earlier than with the previous design methods

An automobile’s exhaust system is becoming more and more critical to its success in the marketplace. Most important, the sound produced by the vehicle serves to a considerable degree as the signature of the brand. For example, an auto enthusiast can recognize the approach of a Bentley or Ferrari with his or her eyes closed. Purchasers of lower-priced vehicles may not be quite so finicky but they still expect to hear a certain sound when they start up the engine. Meanwhile, automotive original equipment manufacturers (OEM) are being forced by government regulations to reduce the levels of noise emitted from the tailpipe. Automakers are also hoping to reduce the back pressure of exhaust systems in order to achieve improvements in fuel economy.

It’s becoming increasingly difficult to meet these often conflicting goals using conventional passive exhaust system technology which relies upon the use of perforated tubes and chambers to filter out acoustic waves. Automotive original equipment manufacturers (OEMs) are looking at active exhaust systems as a way to address these issues. Active exhaust systems use a loudspeaker driven by a microprocessor to cancel out unwanted sound generated by the engine as well as to produce more desirable sounds. A key advantage of active exhaust systems is that they can be controlled by software to adjust the output of the loudspeaker to deliver just the right sound under a wide range of different operating conditions.

“Actran has enabled Tenneco to develop a process for electroacoustic simulation of an active exhaust system including the loudspeaker and housing that correlates very well with physical experiments,” said Nicolas Driot, Senior Core Science Engineer for Tenneco. “We are now using simulation to develop our next generation active exhaust system. Simulation will make it possible to evaluate the performance of many alternative design concepts in a minimal amount of time without the expense of building physical prototypes. This should make it possible to improve the performance of the exhaust system beyond what can be achieved with the traditional process where only a few different design alternatives can normally be evaluated. Simulation will also make it possible to bring new products to market faster.”

• Actran results match very closely with physical test measurements both when modeling the loudspeaker alone and then when simulating the loudspeaker integrated it in a complete exhaust system.
• Simulation allows evaluating the performance of many alternative design concepts for active noise cancellation in a minimal amount of time without the expense of building physical prototypes.

As one of the UK’s leading manufacturing companies, Leyland Trucks Ltd. is PACCAR’s established center for light and medium-truck design, development, and manufacture. Leyland used MSC ADAMS to access ride behavior of trucks earlier in the design cycle. In addition to studies of detailed procedures such as cab tilt, lane-change maneuvers, and ride comfort, MSC ADAMS simulation allowed Leyland to rapidly assess the effect of minute changes in suspension, wheelbase, tires, or payload position. For Leyland, the use of VPD tools led to significant benefits in terms of final design quality and considerable time savings.

As design technology has improved, the details of the truck have evolved almost beyond recognition. For instance, new materials have been introduced in recent years, leading to global initiatives to reduce weight through the use of these advanced high-strength steels. Other design details are changing – trucks are now using disc brakes rather than drums – and Leyland engineers must balance incorporating these details while improving quality and still keeping costs under control.

• A full MSC ADAMS truck model contains a flexible body and chassis, springs, roll bars, axles, cab and engine suspension, the steering mechanism, and any frequency dependent rubber mounts. Extra detail, such as brakes, propeller shafts, and out-of-balance engine forces can be included on an ‘as needed’ basis.
• Simulation also allows several aspects of the operation of crane-bodied vehicles to be better understood, such as vehicle stability on slopes and uneven surfaces, the need for stabilizing legs, and the effects of loading and unloading.

• Significant benefit in terms of final design quality,
• considerable time savings
• A recent project named LF was completed two years faster than the previous equivalent one – in a four-year design cycle rather than six.

The amount of effort required to close the doors of an automobile is critical to the consumer’s perception of its quality. If too high a closing velocity is required, the customer may have a negative impression of the car and the potential also exists for an unpleasant noise to be created by closing the door. The goal for most automobile manufacturers is to require a relatively low effort to close the door while at the same time meeting weather sealing and acoustic insulation requirements.

“The results of the cosimulation were provided to our customer and helped win the order to supply seals for a new model vehicle,” said Dr. H. Tuncay Yüksel, Design Director for Standard Profil. “Now that the simulation process has been developed it will be possible to simulate new seal designs in much less time and at a lower cost than physical prototyping. This will make it possible to evaluate more design alternatives to improve door closing performance as well as reduce the time and cost of the product development process.”

• Adams-Marc cosimulation helps the engineers accurately evaluate the amount of effort required to close the doors, which is critical to the consumer’s perception of its quality
• Co-simulation helps MSC customer to win order to supply seals for a new model vehicle
• Users can now simulate new seal designs in much less time and at a lower cost than physical prototyping.

Mechanical joints with fasteners are widely used for aircraft primary structures to assemble composite parts. In the case of a pin-loaded joint, stress concentration takes place on each side of the fastener leading to the apparition of local failure before the final failure of the assembly. Depends on the geometry of the joint, different failure modes may appear.

Although tests are frequently conducted to support the design of such components, the benefits of a simulation tool such as Digimat is obvious if the material modeling used is able to reproduce properly the damage behavior of the composites (unidirectional or woven reinforcement) in order to predict accurately not only the failure load but also the failure mode.

• Definition of the Progressive Failure Material model for both the UD and woven reinforced composite
• Definition of a parameterized MSC MARC finite element model to seamlessly perform a coupled analysis with Digimat.

• Good reproduction of the failure mode for the tested configuration
• Good prediction of the failure load level
• Possibility to investigate any type of geometry with confidence at no cost.

Airframes are designed to deflect in response to aerodynamic and gravitational loads during flight. These deflections in turn load the mechanisms riding on the airframe that move the primary flight control surfaces to maneuver the aircraft. The airframe manufacturer must ensure that deflections of these mechanisms at any point in the flight envelope do not affect their operation. For example, the Airbus A400M elevator is connected to the horizontal tail plane (HTP) with eight hinges that form a straight line when the wing is undeformed. Seven of these hinges are floating hinges which can float in the hinge line direction. When the HTP structure is loaded, it deforms, deforming the hinge line. The multi body simulation (MBS) model here shows the location of hinge 7 which is used to move the elevator, and the drawing below the model shows a cross-section of the hinge. The gap g2 in the drawing allows the red lug to slide on the green pin.

”The replacement of the physical A350- 1000 wing bending test with simulation of the effects of deflection on the flight controls saved Airbus about €3 million and 4 months on the certification process for the A350,” said Michael Vetter, Project Leader Multi-Body Simulation with Airbus. Most of these savings were achieved by eliminating the need to build test fixtures. Similar savings will be achieved for each future aircraft model. Airbus engineers are also working to apply this same method to other mechanical systems of the aircraft such as landing gear and passenger doors.

• Saving significant time and costs by replacing expensive physical testing with Adams simulation
• Removing the limitation on the number of different load cases and configurations that could be tested by physical test rig
• The simulation results successfully correlated with all of the tests
• These results convinced European Aviation Safety Agency(EASA) that functional testing could be replaced with Adams simulation so simulation is used to certify the A350-1000 XWB wing

The primary function of heavy duty trailer suspensions is to link the trailer to its wheels. This provides a compliant connection which protects the trailer cargo from the shock and vibration inputs developed at the road surface. In addition, the suspension must meet the customers’ expectations for usable life, and do so while being economical to manufacture. One of the challenges of trailer suspension design is that these requirements often conflict with each other. Trade-offs are often required in order to meet these performance requirements over the suspension’s entire operating range.

“We can now simulate a new suspension, in a different trailer configuration, for a specific event, in a matter of hours as compared to the days or weeks that are required with physical testing,” Dr. Patterson said. “The fact that we can change the system much faster in the simulation than on an actual trailer makes it possible to evaluate the performance of our product in more configurations, all while spending less time and money building prototypes and performing physical testing. Of course, we always run a final physical test to ensure the accuracy of our simulations. The end result is that we are able to bring products to market faster, and generate larger revenues while reducing our product development expenses.”

• Simulation results make it possible to see every aspect of suspension behavior.
• Adams results match very closely with physical test measurements on numerous occasions comparing the tire loads, component forces, and suspension performance characteristics, such as ride height change.
• Simulation provides a much better understanding of how the proposed suspension design performs than can be obtained by physical testing.
• Loads determined by the simulation are used to design fatigue tests.

The defining characteristic of a zoom lens is that its focal length can be varied. The focal length determines the angle of view — how much of the scene will be captured — and the magnification —how large individual elements will be. The shorter the focal length, the wider the angle of view and the lower the magnification. The advantage of zoom lenses over lenses with a fixed focal length is that you don’t have to change lenses to achieve a tighter or a wider composition. Most zoom lenses, particularly those designed for consumer and professional photographers, lose focus when the focal length is changed. But high-end zoom lenses, especially those designed for producing films or television, can be zoomed in and out without losing focus. This type of lens is called a parfocal lens. The first parfocal lens capable of zooming in an out while maintaining precise focus to a degree acceptable for demanding cinema production was designed and built by Pierre Angénieux in 1956, a feat for which he received an Academy award for technical excellence. Parfocal zoom lenses are very difficult to design and build. Zoom lenses generally consist of three different groups; two of them are moving together (to change focal length) and the last one independently (to focus) and one stationary group of lenses with each group comprising two of more lens elements.

With the new method proven, Ayad simulated all of the company’s zoom lenses and found the worst-case position for each lens. Now inspectors are able to inspect the tilt simply by moving the lens to this position and making the measurements. The net result is that the time needed to inspect each lens has been reduced.

• Inspection time has been reduced
• Less experienced operators can perform the inspection
• Adams simulation accurately predict worst case position

It takes a 450 horsepower truck with an 80,000 lb. load roughly 90 seconds to accelerate to 50 mph but the brakes must be able to stop the truck in less than 5 seconds. Air brakes are used almost exclusively in heavy-duty trucks and trailers because they offer the following advantages. First, the air they run on is free. It only needs to be compressed, cleaned, stored and distributed. The air brake circuit can be easily expanded so trailers can be coupled and uncoupled from it. Besides providing the energy required to stop the vehicle, compressed air also signals when and with how much force the brakes should be applied in any situation. Finally, air brakes can be designed with sufficient fail-safe devices to bring the vehicle safely to a stop, even in the event of an air leak. Reinforced rubber hoses deliver air from fittings on the frame to brake chambers on the axles. In a typical tandem rear suspension there are typically 8 brake hoses plus additional hoses for the power differential lock and other features for a total of 11. The hoses must be routed through a tight space and accommodate the full range of steering gear and suspension travel. The hoses are required to avoid contact with components with sharp edges that might wear the hoses, maintain a specified minimum bend radius to avoid constricting flow within the hose, and avoid axial forces high enough to pull out the hose out of the fitting.

“Simulation makes it possible to try many different positions, orientations, and clipping options early in the design phase prior to the availability of a prototype,” said Stefano Cassara, Manager Vehicle Dynamics Simulation for Navistar. “New design iterations can be evaluated in a small fraction of the time required for physical testing. The new approach makes it possible to design new hose configurations in only about two weeks. Since the design process will be carried out early and outside the critical path we should be able to bring new vehicles to market six weeks faster than in the past. Another advantage of the new approach is that we can model loading scenarios, such as braking, that cannot be duplicated on the test rig.”

• Simulation of hose routing helps reduce time to market by six weeks
• Adams predictions perfectly matched test results in each steering position
• Simulation provides a much better understanding of how to route the braking hoses to avoid contact with components with sharp edges that might wear the hoses in response to suspension and steering movement
• New Adams FE Part provided a fast and accurate way to predict the large deformation of brake hoses in Adams environment