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pageIcon-RailwayThe age of faster, longer, safer, quieter and more environmentally friendly trains is here. Safety is the paramount objective of any train design and cannot be compromised at any cost. Physical testing formed an integral part of design in the 1990s, until CAE demonstrated that many complex and unsafe tests could be simulated on a desktop. The NISA product line has helped the railway industry for the last two decades in analyzing many such tests and problems.

Please click the tabs below to navigate through the Railways case studies.
 

Locomotive Canopy
Break Resistor
Heat Sink

Structural analysis of a locomotive canopy made of composite material

Objective:

Composites are finding increased use in new age locomotives, because they are so lightweight and make more aerodynamic shapes possible. Structural analysis of a locomotive canopy was to be carried out to determine the static response of the composite structure under mechanical and aerodynamic loads.

Methodology:

The canopy of the engine was made of composite shell structure stiffened with orthogonal ribs on the interior surface. The entire unit was assembled from three sub-assemblies. The windshield of the canopy was made from laminations of bulletproof glass while rest is made of glass fiber reinforced plastic (GFRP). The canopy was fixed to the base frame of the locomotive by means of fasteners. The pressure field obtained from the CFD analysis was transferred to the structure to determine the static structural response. The stresses developed in the canopy skin and the ribs for the initial design at the front of the canopy were observed to be above the allowable limit. The skin thickness of the canopy including the bottom flange was therefore increased. The manufacturer saved on expensive physical trials.

Flow analysis of railway break resistor

The railways complained about the failure of a few electric locomotive brake resistors during certain braking conditions. Computational fluid dynamic analysis determined that inefficient cooling at the brake tips was the cause. A design change was incorporated which prolonged the life of the resistors considerably.

Cooling analysis of a heat sink

The above-shown heat sink allows the fast dissipation of heat from various electrical parts under a railway bogie. The fins of the heat sink point downwards and allow for air to pass through them when the train is in motion. A major railway parts manufacturer wanted to increase the efficiency of its heat sinks. Computational fluid dynamics and thermal analysis were conducted and a wavy-fin profile was suggested to increase efficiency.

 

pageIcon-MedicalMedical imaging provides important data on various body structures for diagnostic reasons. This data is now being used to obtain geometric information of body structures in 3D models, which can be analyzed through FEA techniques for the design of various products like coronary stents, pacemakers and orthopedic/dental implants. For device manufacturers there is a common goal, to introduce improved and safer products before the competition does while conforming to FDA standards. The NISA product line has been helping the medical industry for the last two decades in designing and analyzing many breakthrough products which can improve quality of life for many people.

Please click the tabs below to navigate through the Medical case studies.
 

Heart Valve
Inhaler
Lower Jaw
Coronary Stent
Orthodontic Wire Stress

Structural analysis of leaflet for mechanical heart valve

Objective:

A heart valve manufacturer in the USA needed a come-up with an optimally designed heart valve.

The most important component of a heart valve is a leaflet which regulates the flow of blood. The leaflet is hinged at the broad-end to the inside of the cylinder which sits inside the artery. Since it is a mechanical heart valve working without an external power source it is important to design the leaflet to reduce drag and mechanical losses at the hinges.

Methodology:

Finite element models were generated using parametric method to allow easy modification of the design parameters for optimal design. The profile of the leaflet was generated using ‘computational fluid dynamics’ to reduce drag. Several different mounting methods were studied to arrive at the optimal hinge mechanism. The manufacturer was able to launch a unique valve into the market in record time.

Flow analysis of medicine in an inhaler

For medical device manufacturers there is a common goal: to introduce improved and safer products before competition does while conforming to FDA standards. A leading pharmaceutical company needed to manufacture a medicinal inhaler in which medicine wastage would be negligible and delivery into the mouth would be highly efficient. Computational fluid dynamics analysis was carried out to accomplish this.

FE modeling of lower jaw

For medical device manufacturers there is a common goal: to introduce improved and safer products before competition does while conforming to FDA standards. A dental implant manufacturer needed to determine forces on a lower jaw bone during various chewing conditions. Stress analysis was conducted for various service conditions.

Nonlinear stress analysis and life estimation of a coronary stent

For medical device manufacturers there is a common goal: to introduce improved and safer products before competition does while conforming to FDA standards. A coronary stent manufacturer needed to determine the durability of the stent. Stress and fatigue analysis was conducted for various service conditions.

Structural analysis of a tooth subjected to orthodontic wire stress

For medical device manufacturers there is a common goal: to introduce improved and safer products before competition does while conforming to FDA standards. A medical university orthodontic department needed to study the effect of a wire and bracket on a canine tooth. Stress analysis revealed the stress distribution in the tooth and safe handling stress.

 

pageIcon-MarineToday's shipbuilders are required to bring out new, innovative designs to the market, that are faster, cheaper and better than ever before. Present-day defense ships need to carry large sophisticated communication systems on deck which need to be designed to function normally even during rough sea conditions. They need to design decks of aircraft carriers for aircraft/helicopter impact. The NISA product line has been helping the marine industry for the last two decades to analyze many such scenarios in commercial and defense vessels.

Please click the tabs below to navigate through the Marine & Naval case studies.
 

Marine Radar
Marine Radar Platform
Rotating Radar
Battery Tray

Structural analysis of a two-axis marine radar system

Objective:

Battleships rely on radars to capture enemy and navigation data accurately. The radar system consists of two parts: the payload, which is the receiver and its sensitive electronics, and the mechanical system that carries the payload. Mechanisms are of different types: single-axis, dual-axis, rotating and swivel. They need to be extremely robust for the payload to capture accurate data. A dynamic analysis of a two-axis radar system was to be carried out to determine the dynamic response at payload locations.

Methodology:

All major structural members were modeled with solid brick elements. Spindles were idealized using 3D beam elements and other major components were modeled using 3D point mass elements. Static analysis was performed for self-weight along with the wind loads. The equipment was also studied for dynamic response under frequency response and bump test conditions. In order to keep the natural frequency above operating range, the structure was modified by adding vertical stiffeners at the cradle. It was found that stresses and deformations under frequency sweep and bump test conditions were within allowable limits.

Structural analysis of a single-axis stabilizing marine radar platform

Objective:

Battleships rely on radars to capture enemy and navigation data accurately. The radar system consists of two parts: the payload, which is the receiver along with its sensitive electronics, and the mechanical system that carries the payload. Mechanisms are of different types: single-axis, dual-axis, rotating and swivel. They need to be extremely robust for the payload to capture accurate data. A dynamic analysis of a single-axis stabilizing platform system was to be carried out to determine the dynamic response at payload locations.

Methodology:

All major structural members were modeled with solid brick elements. Ball screws were idealized using 3D beam elements and other major components were modeled using 3D point mass elements. Static analysis was performed for self-weight along with the wind loads. The equipment was also studied for dynamic response under frequency response and bump test conditions. In order to keep the natural frequency above operating range, the structure was modified by adding vertical stiffeners at the cradle. It was found that stresses and deformations under frequency sweep and bump test conditions were within allowable limits.

Structural analysis of a single-axis rotating type marine radar system

Objective:

Battleships rely on radars to capture enemy and navigation data accurately. The radar system consists of two parts: the payload, which is the receiver along with its sensitive electronics, and the mechanical system that carries the payload. Mechanisms are of different types: single-axis, dual-axis, rotating and swivel. They need to be extremely robust for the payload to capture accurate data. A dynamic analysis of a single-axis radar system was to be carried out to determine the dynamic response at payload locations.

Methodology:

All major structural members were modeled with solid brick elements. Spindles were idealized using 3D beam elements and other major components were modeled using 3D point mass elements. Static analysis was performed for self-weight along with the wind loads. The equipment was also studied for dynamic response under frequency response and bump test conditions. In order to keep the natural frequency above operating range, the structure was modified by adding vertical stiffeners at the cradle. It was found that stresses and deformations under frequency sweep and bump test conditions were within allowable limits.

Structural analysis of a marine battery tray

Objective:

Battery power plays an important role in ships and submarines. Batteries are constantly charged by generators coupled with engines to provide constant reliable power. Since the number of batteries is generally large they are placed in arrays in trays. The trays need to be designed to withstand the heavy weight of the batteries and any impact they might experience during operation. A manufacturer needed to perform a finite element static and dynamic analysis for a battery tray for various loading conditions.

Methodology:

The whole structure was idealized using shell, beam and mass elements. Static analysis has been performed for self-weight and mass of the battery. Transient dynamic analysis was carried out to analyze the battery tray for shock and impact. A frequency response analysis was carried out for constant amplitude and acceleration vs. frequency.

Static analysis results were within allowable limits. Stress and displacement values for shock and frequency analysis (for ground excitation and amplitude) were higher along transverse directions. The tray was qualified for maritime use.

 

pageIcon-EnergyEveryone is inconvenienced when power plant equipment fails, and most importantly it affects the company’s revenues through productivity shortfalls. Steam turbines, gas turbines, axial/radial flow compressors, hydro-generators and boilers are extremely dynamic systems which need to be simulated and analyzed rigorously to avoid catastrophic failures. The NISA product line has been helping the power industry for the last two decades in analyzing a wide array of dynamic power equipment, including nuclear power.

Please click the tabs below to navigate through the Energy & Power case studies.
 

Hydro-generator Cooling
Buried Power Cables
Condenser Unit
Control Panel
DC Generator
Power Plant Rotor

Hydro-generator cooling analysis

Objective:

Depending upon rating and design, a hydro-generator stator core and windings may be cooled by air, oil, hydrogen or water. For direct-cooled generators, the coolant is in direct contact with the heat producing members such as the stator winding. For any generator, a failure of the cooling system can result in rapid deterioration of the stator core lamination insulation and/or stator winding conductors and insulation. A manufacturer needed to optimize the gap between fan blade-baffle and fan blade-air guide and parameterize the ventilation system of hydro generator for different blade configurations.

Methodology:

3.6° segment was considered for the analysis. A parametric 3-dimensional CFD analysis was carried out for different gaps and flow rates. Flow was considered steady and incompressible. It was observed that an 8-millimeter gap between fan blades and the air guide was optimum at all flow rates. Flow reversal was observed at larger gaps. This optimum cooling increased the efficiency of the generator.

Thermal analysis of buried power cables

Objective:

Underground power cables carrying high-ampere current generate large amounts of heat. The metallic wires are bunched in various geometries and are enclosed inside a polymer cladding which protects them from the elements such as water, heat, corrosive materials and fire. Cable manufacturers need to determine the heat flow inside the cable so as to prevent meltdown of the cladding. Cladding meltdown results in obvious risks such as electrocution and disadvantages such as power transmission loss. When these cables are placed together in groups, the problem of cladding meltdown is compounded.

Methodology:

Conduction is the accepted mode of heat transfer below ground level. Two-Dimensional Thermal analysis was carried out. For this evaluation of thermal capacitance for the model was done under steady-state equilibrium conditions. The analysis was carried out for single cables and a group of cables laid together. Different conductor shapes like round and oval were considered. Temperatures at steady-state were found to be well within limits for the cases discussed.

Structural analysis of 36-inch condenser unit for nuclear application

Objective:

This project was undertaken to understand the structural, thermal and seismic responses of a horizontally mounted condenser unit used for a nuclear waste treatment facility. The condenser unit was built in the northwest United States for the Department of Energy.

Methodology:

A finite element model of all the major components of the condenser unit was constructed using shell elements. The model consisted of the main vessel, channel shell, plenum shell and closures, heads, saddles, nozzles, tube sheet and internal baffles that support the tubes.

The assembly was subjected to nozzle loading, internal pressure due to various chambers being full or under vacuum, thermal loads and piping thermal loads as specified by the client in accordance with the ASME section VIII Division 1 guidelines.

The seismic response due to acceleration in all three directions was calculated and compared to the allowable stresses used as generally accepted practice in the nuclear industry. Fundamental frequency of vibration was calculated to meet the design requirements.

The unit conformed to the ASME Section VIII Div 1 guidelines.

Dynamic stress analysis of a control panel

During seismic activity, it is important that the control panels of a power plant do not lose their structural integrity. Dynamic stress and seismic analysis were conducted on one such control panel. The panel was qualified for installation thereafter.

Electromagnetic analysis of a DC generator

Determining magnetic vector potential and flux density distribution in a DC generator is crucial if the generator is to perform according to design and with minimum power loss. Electromagnetic analysis was conducted for a major generator manufacturer to qualify its design.

Dynamic analysis of 220-MW power plant rotor

Structural integrity of generator rotor shafts under any service condition is paramount. A major electric generator manufacturer needed a 220-MW rotor shaft qualified. Dynamic rotor analysis was conducted to determine if the shaft will survive most service conditions.

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