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pageIcon-ElectricalIt’s a fact: the higher the PCB (Printed Circuit Board) temperature, the lower the electrical performance of an electronic device. With electronic component and power density on present-day PCBs being higher than ever, it's difficult for a PCB designer to ignore thermal effects. Thermal analysis assists the designer in determining the electrical performance of the components on the PCB, and it also helps the designer determine if the component or PCB will burn up due to high temperatures.

Natural or forced convection from the front and back surfaces, conduction from the edges of the PCB to walls of an electronics box, conduction through rigid or flexible connectors to other PCBs, conduction from PCB to mounting frame and conduction to heat sinks are just some of the scenarios that can be analyzed using NISA. The NISA product line has been helping the electronics industry for the last two decades in designing and analyzing safe and efficient products.

Please click the tabs below to navigate through the Electronics Packaging case studies.
 

Cooling Analysis/PCB
Thermal Analysis/PCB

PCB housing cooling analysis

Objective:

Overheating of electronic components in an enclosed geometry is an important study in today’s age of miniaturization. A manufacturer needed to determine the amount of thermal power dissipation into the resistor (in yellow in “FE model”), in order to maintain the IC (in green) temperature of 85°C, at different atmospheric temperatures.

Methodology:

Passive electronic components were modeled with beam, shell and solid elements. The heat transfer coefficient was calculated analytically for different ambient temperatures. Combined conduction and convection heat transfer modes are considered. Steady state heat transfer analysis was carried out for the heat dissipation into the resistor so as to maintain the IC at 85°C. The heat flux to be transmitted to the resistor at an ambient temperature of 25°C was found, so as to maintain the temperature of the IC at 85°C.

Thermal and stress analysis of a PCB

With component density on PCBs on the rise, thermal failure of these boards needs to be studied. A large computer PCB manufacturer needed to determine the optimum number of components and their layout. Thermal stress analysis was conducted to qualify the PCB board for various service conditions.

pageIcon-AutoWith new models of cars and SUVs doled out by manufacturers every day, engineering lead times have been reduced significantly. The budget slice for physical testing has been drastically reduced, and in some cases physical testing is just not an option. Lead times for automotive majors have been reduced from 50+ months in the 1990s to 15 months with the adoption of CAE. Physical testing which used to involve large investments and 4-6 months has been replaced by CAE simulation which can accomplish the same task in 1-2 months with much smaller investments. The NISA product line has been helping the automotive industry for the last two decades in analyzing many complex problems.

Please click on the tabs below to navigate through the Automotive case studies.

Heavy Truck
Alternator
Chassis
Rod & Crankshaft
Instrument Panel
Bus Body
Motorcycle Crank Case
Motorcycle Exhaust
Scooter Wheel Hub
Shear Pin Assembly

Design analysis of heavy duty truck cab

Objective:

A Canadian logging truck manufacturer needed the cabins of its trucks designed for crushing loads from falling trees and impact from logs being carried on the trailer. The truck cabins needed to pass a beam penetration test.

Methodology:

All cabs are required to pass several different operating loads as specified by the manufacturer and governmental regulations.

Crush analysis was conducted, which simulates forward moving logs penetrating the cab from the rear panel if a fully loaded truck were to stop suddenly. In addition, depending upon the application of truck, the cab is required to withstand localized loads such as roof crush, snow load and beam penetration due to either falling trees or light/sign poles. The model consisted of shell elements for the cab. The panels were connected using rigid links for spot-weld simulation. The frame and suspension were included using beam elements.

The truck cabins were suitably reinforced and the manufacturer passed government regulations.

Airflow and thermal analysis in an automotive alternator

An automotive alternator manufacturer re-engineered an alternator which was to be fitted into a popular car. The highlight of the alternator was its fan-less design. Fins on the stator and rotor moved relatively to each other creating a natural suction for air. In order to determine if the device would cool itself suitably in all thermal conditions, computational fluid dynamics analysis was conducted to qualify the device.

Analysis of an automobile chassis for various road conditions

An automobile manufacturer was to launch a sports car for Indian road conditions. Indian roads are notorious for deep pot-holes which can cause extensive damage to suspension and chassis. The stress/vibration analysis was conducted on the chassis, and various g forces were simulated in the process.

Fatigue analysis of an automobile connecting rod and crankshaft

An automobile engine manufacturer complained of premature failure of a connecting rod and crankshaft. Stress/fatigue analysis were conducted to determine the life of the components after redesign.

Vibration analysis of an instrument panel of an automobile

A major SUV manufacturer complained of unnecessary vibration of the instrument panel, especially in the region of the entertainment center. Modal analysis was conducted to identify this vibration and miniscule design changes were made to nullify it. This SUV in full-scale production is now commended for having one of the quietest cabins.

Random vibration analysis of a bus body

A bus body manufacturer was to launch a local transport bus for Indian road conditions. Indian roads are notorious for deep pot-holes which can cause a vibration of the bus body. The random vibration analysis was conducted on the body to check structural integrity during most service conditions.

Vibration analysis of a motorcycle crank case

A motorcycle manufacturer complained of excessive vibration/ sound from the crankcase at certain throttle levels. Vibration/modal analysis was carried out and it was determined that the cause was a mass imbalance inside the crank case. A small mass in the form of a plate was fitted inside the crank case and the vibration was eliminated at all throttle levels.

Vibration analysis of a motorcycle exhaust system

A motorcycle manufacturer complained of premature failure of an important rubber washer at the flange connecting the exhaust to the engine outlet. Vibration/modal analysis was carried out and to determine that the cause was unwanted vibration of the exhaust pipe. The bracket connecting the exhaust to the main body was shifted by a small degree and the vibration was eliminated.

Structural analysis of a scooter rear wheel hub during acceleration and braking

A scooter manufacturer complained of premature failure of a wheel hub under certain road conditions. Stress and Vibration Analysis determined that it was the clamp joining the hub to the wheel rim that was the cause for failure. A new clamping mechanism was designed to re-qualify the vehicle

Structural analysis of a shear pin assembly for a bucket excavator

A major manufacturer of heavy machinery complained of the failure of the shear-pin assembly of one of it bucket excavator models. Stress Analysis was conducted on the assembly and it was determined that the geometry of the shear pin needed change.

pageIcon-AerospaceBudget squeezes in the military and commercial aerospace industry are here to stay. For the military, efficient product development management and product life cycle costs are the key in awarding contracts; whereas, for the commercial sector it is necessary to build larger, faster and more economical planes with the same constrained budgets. The bottom line is the aerospace industry is looking at affordability. The NISA product line has been helping the aerospace industry for the last three decades in analyzing complex problems which in many cases would be prohibitively expensive to test physically.

Please click on the tabs below to navigate through the various Aerospace case studies.

SDP Unit
Antenna
Ground Radar
Antenna Housing
Gimbal Systems
Aircraft Wing/Composite Material
Antenna Support
Satellite/Thermal Management
Tire Contact
Antenna Cabin
Avionic Instrument
Helium Balloon
Stage Separation

Conjugate heat and fluid analysis of SDP unit

Objective:

A surveillance data processor (SDP) processes radar and surveillance data. It performs tracking and alert processing for aircraft violating separation minima with other aircraft or restricted airspace. The SDP typically has many heavily componentized cassettes in series and in close proximity to each other. When in operation the device generates copious amounts of heat, therefore making it essential that the instrument cool itself satisfactorily to avoid burnout. A fluid-heat analysis was to be conducted to make the instrument airworthy.

Methodology:

A conjugate heat and fluid analysis was to be conducted on the SDP unit to check the airflow pattern and temperature distribution within the unit. It was modeled with 3D hexahedral elements by an iterative process for several modifications in the flow domain to optimize the flow pattern and temperature distribution. Flow of air was considered incompressible and steady. The instrument was declared airworthy.

Structural analysis of planar printed array antenna

Objective:

Printed array antennas are one of the most sensitive devices on an aircraft, having sensitive electronics on their surfaces that process the data they receive. An antenna needs to be designed optimally and perform satisfactorily in adverse conditions.

Methodology:

The antenna structure was idealized using shell, beam and mass elements. Static analysis was carried out for a range of operating ambient temperature. Dynamic analysis was carried out for shock, sinusoidal and random vibration for the flight envelope.

It was determined that the fundamental frequency was greater than the upper limit specified for frequency sweep. The maximum deflection occurred in crash hazard loading conditions, and the maximum von Mises stress occurred during temperature loading and was a highly localized phenomenon restricted to the fixity region. The antenna was redesigned and passed as airworthy.

Conjugate analysis of C and X band array assembly of ground radar

Objective:

Phased array antennas that can be steered electronically are finding increasing applications in both radar and communication systems. Phased array radar systems offer many advantages over mechanically swept antennas, the most notable being their ability to select a given azimuth and elevation pointing angle without physically moving the antenna. This is probably the best way to track or search many targets widely separated in space. The phase control module (PCM) forms the core element of the phased array radar and helps it in electronic scanning of an RF beam.

PCMs generate heat and many of them in close proximity can increase the surface temperature of the radar surface. Conjugate fluid-heat analyses needed to be carried out on C- and X-band array assemblies to check the flow pattern and temperature distribution within the array housing.

Methodology:

The assemblies were modeled with 3D hexahedral elements and modified iteratively to optimize the air flow pattern and temperature distribution between the PCMs and radar surface. Natural airflow and force airflow from a fan were studied.

The defense department saved on time and expenses by analyzing the simulation rather than physical testing.

Lift and drag analysis of aircraft antenna housing

Objective:

Radar attached to the top of the fuselage of a surveillance plane was to be analyzed for lift and drag force due to the slide of aircraft in the air, at different altitudes, speeds and slide angles.

Methodology:

3D external compressible fluid flow analysis was carried out. The analysis was carried out at different mach numbers, different altitudes and different slide angles. The analysis was carried out at a height of 50,000 feet, Mach number of 0.7 and slide angles of 0°, 5°, and 10° and 20 °. Increase in the slide angle increases the force. The drag forces obtained by parametric study were presented in the table.

Frequency-based composite design for multi-axis gimbal systems

Objective

A company in the USA has developed a line of lightweight, advanced composite, multi-axis gimbals for use in precision applications. A gimbal is a device using Euler angles to measure the rotation of an object in three dimensions and to control that rotation.

To ensure that the structural frequency of the high-modulus gimbal meets the control system specifications, finite element analysis is required to accurately predict its structural response.

Methodology

FEA models are first generated to include composite shell elements, solid bricks for the drive components, and general springs for bearings and fasteners. Spring constants are calculated to represent bearing axial and radial stiffness values, and the fasteners used within the structure. Mass elements are added as required to represent the payload, motor and other ancillary equipment embedded within the gimbal.

Eigenvalue analysis is conducted to extract eigenvalues using the Lanczos method, with stress, strain and displacements saved for post-processing. Composite ply schedules are varied until the first participatory mode meets the control specifications.

The company now has a convenient spreadsheet which has a listing of the modal participation factors of the critical modes. The company saved time and costs by not fabricating a gimbal using a complicated manufacturing process.

Vibration analysis of an aircraft wing and fuselage made of composite material

The use of composites in ultra-light aircrafts is only natural. Low weight and high strength are two attractive features which make them highly desirable. A newly designed all-composite aircraft was to be launched in the market. Stress and vibration analysis was conducted on the wing and fuselage section of the aircraft, after which it was approved for production. The manufacturer saved on time and physical testing costs.

Analysis of an antenna support platform for flightworthiness

The electronics on a satellite antenna are extremely sensitive and delicate. Because of this they need to be supported on a structure which is robust and undergoes minimal deformation during flight. Vibration analysis of an antenna support platform was conducted to qualify the assembly for flightworthiness.

Analysis of satellite for thermal management

A satellite in orbit around the earth is exposed to different temperature conditions at various positions. Any excessive absorption of solar flux by the satellite will result in malfunction of the electronics on board or even compromising of the mission in extreme cases. Thermal analysis was conducted to study the amount of heat absorbed by the faces of the satellite during various orbit positions, to qualify the satellite for safe deployment.

Aircraft tire contact analysis

Aircraft tires are made of multiple plies of composite materials, both metallic and non-metallic, making them extremely difficult to study. An aircraft tire making contact with the tarmac during landing is a high-energy elasto-plastic process extremely detrimental to the tire. Tire contact analysis is paramount to tire companies who would like to increase the durability of their tires. Contact analysis was conducted on the tire under various loadings (aircrafts types, speeds, ground conditions, etc.) to the satisfaction of the manufacturer. The manufacturer saved on exorbitant testing costs associated with these types of physical tests.

Random vibration analysis of antenna cabin

The antenna is an extremely sensitive and delicate part of a satellite. Because of this it is generally placed inside a cabin when being transported and when it is deployed in space. The structural integrity of the cabin is paramount if it has to protect the antenna. Random vibration analysis was conducted on the cabin in the transportation and deployed mode to ensure safe passage of the antenna. The agency saved on time and physical testing costs.

Analysis of an avionic instrument for flightworthiness

Avionics equipment in supersonic combat aircrafts is subject to extreme gravitational forces during certain maneuvers. Any damage to important instrumentation can turn detrimental to the mission. Stress analysis, vibration analysis and modal analysis were conducted to ensure the flightworthiness of an instrument. Various gravitational forces were simulated and design changes to the housing and supports were suggested. The air force saved on time and testing costs.

Analysis of a helium balloon

Hot air balloon enthusiasts need to have an inner helium balloon inside the normal hot air canopy when traveling at high altitudes. The area below the helium balloon forms a cone into which hot air is fired through gas tanks. A hot air balloon enthusiast wished to make a record breaking attempt at flying around the globe non-stop. Computational fluid dynamic analysis was conducted on the balloon which consisted of studying the effect of the sun’s heat on the helium at various times of the day and the optimum amount of heat to be fired into the air cone below the helium balloon to maintain optimum altitude. Highly expensive and cumbersome physical testing was avoided in this case.

Stage separation in space vehicle

Stage separation after lift-off is one of the most crucial maneuvers a space vehicle has to undergo during its mission. Improper separation can cause the space vehicle to go off course and compromise an entire mission. The reactionary force on the two separating surfaces due to a controlled explosion is an important aspect to study. Computational fluid dynamic studies on the two separating surfaces were performed to ensure perfect separation. The agency saved on time and exorbitant testing costs.

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