Mechanical Engineering Portfolio

Rohit Bhagat,

Master of Science in Mechanical Engineering,

University at Buffalo, State University of New York

Phone: 858-249-8569

Email: rohitbhagat6@yahoo.com

LinkedIn: www.linkedin.com/in/rohitbhagat611

1. Design and Fabrication of Automated Grinding and Fan Winnowing Station (Freelancer) April 2015-

Present Aim: To design and fabricate a cocoa bean grinder and winnowing station with a capacity to hold 50 kg beans.

Implementation: Design and selection of the components like hopper, crusher, structural members, motors,

controller, vibrating table, sieves, vacuum unit, etc. Created a 3D model and performed FEA on critical parts.

3D model of the vibrating system

3D model of the grinder and winnowing station assembly

Conclusions:

The design satisfies the customer requirements.

FEA shows the design is safe.

The project is still in progress and would be manufactured soon.

Vibrating

table

Sieve

Chute

Vibrating

Motor

Spring &

Standoff

assembly

Hopper

Crusher

Vacuum

Unit

2. Design and Fabrication of Vertical Reciprocating Conveyor (VRC) (Fall 2012-Spring 2013, DECON Pvt

Ltd, India)

Aim: To design and fabricate a semi-automatic material handling lift with a capacity of 1000 kg.

Implementation: Developed an optimum design procedure for a semi-automatic material handling lift with a payload of 2

ton. Created a 3D model of the VRC and performed FEA on the critical parts. Incorporated safety features including safety cam, chain tensioner, electro-mechanical door locks & top/bottom safety switches.

3D Model of VRC and its carriage

Drive assembly and Safety cam

Stress and Deformation analysis on the carriage using ANSYS workbench

Stress and Deformation analysis on the drive assembly using ANSYS workbench

Stress and Deformation analysis on the structure using ANSYS workbench

Layout showing the safety and control features incorporated in the system

Conclusions:

• Safe and reliable design.

• Satisfies the problem statement.

• Safety of structure was also verified by Simulation tools.

• High positioning accuracy obtained.

• Less noise during operation.

3. Cable Driven 3D Printer: a Novel Additive Manufacturing Machine (Spring 2014, University at Buffalo)

Aim: To develop a novel 3D printer concept which doesn’t exist in the commercial market.

Implementation: Cables were implemented for extruder motion in order to provide large work space, faster posiitioning,

eliminate moving platform and for simple and reconfigurable design. The concept was inspired from cable driven robots

and the sky cam. Modeling and control of a cable driven 3D printer were studied in detail. The printer was designed for 3

degree of freedom, with motion of the extruder in X, Y, Z directions. Kinematic and static analyses were performed on the

cables and the extruder mounting plate to determine the position of the printing head and the force exerted on it to

maintain static equilibrium.

Cable Driven 3D printer

Extruder

Spool & its shaft

Outer frame

Spool mounting rod

Bottom Frame

Top Frame

Protective Glass

Heating Bed

Extruder

Stepper Motor

Extruder Frame

Heating Coil

Nozzle

Spur Gears

Mounting plate

Cable attachment screws

Filament carrying tube

Cooling Fan

Exploded view of Extruder & the whole assembly

FEA on 3D printer frame, printing platform and platform mounting plate

Conclusion:

Inexpensive, simple and lightweight 3D printer.

Flexibility to print large as well as small objects, even of irregular shapes.

The setup is easily reconfigurable and any addition of cables, motors or pulleys can be done effortlessly

Would provide faster build rate.

Extruder motion would be very precise considering the Kinematics and static analysis.

4. Shark Skin Structure on a UAV to Reduce Drag: 3D Printing Approach (Spring 2014, University at

Buffalo)

Aim: Investigating the optimization of shark-mimicking riblet structure geometry for Unmanned Aerial Vehicle (UAV)

wings to be fabricated using additive manufacturing. Studying the drag reduction after the incorporation of scales.

Implementation: The effect of shark-mimicking riblet structure geometry for drag reduction in UAV design were

modeled and simulated. This modeling phase was then linked to an optimization process to derive optimum riblet

structure geometry parameters. In addition, preliminary results of 3D printed shark riblet structure geometry were also

outlined.

For optimum riblet geometry, a part of the wing was considered.

3D Model of (a) Blade (b) Scalloped (c) Saw tooth geometries

3D Model of UAV wing with blade riblets

Modeling and FEA of UAV wing, with & without scales

Conclusion:

• Incorporation of blade riblets on the UAV wing reduces drag by approximately 7%.

• A 7% reduction in drag can have a considerable impact on fuel consumption of the aircraft and help lower costs.

• In future, this result could further be validated by a wind tunnel test.

• Fused Deposition Modeling gives relatively poor precision and hence other printing methods can be looked into.

• Blade riblets can also be incorporated on fuselage and the tail of the aircraft to further improve efficiency.

• Parts can be optimized for the FDM process such that only build material is required without any support

structure, thus giving considerable cost savings.

5. Optimizing Number & Placement of Dampers in Earthquake Prone Buildings (Fall 2014, University at

Buffalo)

Aim: To optimize the number and locations of tuned mass dampers that are installed in high-rise buildings.

Implementation: A model presenting the connection between drifts and the number of tuned mass dampers for an n-

storey building was developed. Then genetic algorithm method was used to optimize the total number of dampers in the

building and some tests were applied to optimize the location of dampers. A comparison was set up between a 10-storey

building optimized using the proposed method, and same building with all floors damped.

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The above equation was used to find out the minimum number of dampers using Genetic Algorithm toolbox from

MATLAB. Bounds were set on the damper and building parameters to find the minimum number of dampers. A state

space model was created and trials were performed to try out different orientations of dampers. The optimum combination

found out was 2 dampers on each of the 10th, 9th& 8th floors, 1 damper on 7th & 5th floors and none on the remaining floors.

This was then compared with a full damped building consisting of 1 damper on each floor to check the responses.

Response of the 8th floor with full damped building

Response of the 8th floor with the proposed approach

Conclusions:

A 10 storey building model under seismic excitation was used for comparison. Genetic algorithm provided an

effective way to minimize the number of dampers. It also allowed us to set the bounds on the parameters. The

minimum number of dampers obtained was 8.

A state space model was used to plot the response of each floor.

The comparison between the 2 methods showed us that the relative drifts for all the floors are within the limits

even after reducing the number of dampers. This would result into significant cost saving.

Choosing the best damper and its installation location is very crucial for structural safety, this general approach

can surely form the basis of calculations for the same.

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6. Automated Manufacturing Process of a Lifting Trolley (Fall2014, University at Buffalo)

Aim: To develop a manufacturing plan and implement automation for production of an industrial lifting trolley.

Specifications:

It can lift up to 1000 pounds of load.

Platform dimension:48 x 38 inches

The maximum height of the scissor is 46 inches.

The motion of platform is achieved with a single cylinder.

Minimal finish requirement.

Implementation: The topics covered in this project were final design, parts to be manufactured/sourced, process plan,

factory layout, machine quantity and production timings, optimization of process, automation and its implementation,

prototyping.

3D Model of the lifting trolley

Fabricated prototype of the lifting trolley

Conclusions:

Implemented automated process for production of lifting trolley.

Successfully incorporated cellular manufacturing in process plan.

The optimization model can be used to reduce total production time.

Automation processes can be easily modified as per the requirement.

Platform

Mounting

Plate

Cylinder

Base Frame

Scissor Arm

Handle

Wheel

7. Modeling and FEA of a Plane and a Power Drill (Spring 2014, University at Buffalo)

Aim: To create 3D models of airplane and power drill and to perform FEA on the same.

Implementation: 3D models for airplane and power drill were created using SolidWorks. Isometric and exploded

views were also obtained. Bill of materials was generated.

Stress and Deformation analysis on the airplane

Isometric and Exploded View and BOM of airplane

Stress and Deformation analysis on the power drill

Isometric and Exploded View and BOM of power drill

Conclusion: 3D modeling and FEA analysis was effectively carried out using SolidWorks

8. Implementing Arduino microcontroller to calibrate a thermistor and control a stepper motor (Spring 2014,

University at Buffalo)

Aim:

a) To calibrate the thermistor to provide an approximate temperature reading.

b) To create 2 modes in arduino sketch, one that will light up the LED when the thermistor is touched and giving the

temeprature reading continuously. Second mode would allow to send the steps for the stepper motor.

c) To make the LED blink which is connected to port no.13 when the motor is moving.

Implementation: Online arduino tutorials were followed to make the proper connections and to write a code to fullfil the

aim of the assignment.

Thermistor calibration

This assignment was performed to calibrate the thermistor with the help of Arduino Microcontroller. A code was written

in the Arduino sketch, such that, the Led light up when the thermistor was touched also giving the temperature reading

continuously.

Output:

Code written in the Arduino sketch and its output

Connections

Control of stepper motor

The assignment was to control the stepper motor with the help of Arduino microcontroller.A code was written to send

steps manually and the LED should light up when the motor is in motion.

Connections

Conclusion: The thermistor and the stepper motor were effectively controlled with the use of Arduino.

9. Design of a Conveyor System for a Coal Handling Plant (Spring 2013, University of Pune)

Aim: To design a trough belt conveyor system with a load carrying capacity of 70 TPH.

Implementation: Selected a suitable standard belt for the given load and speed. Designed the Head pulley, tail pulley

and snub pulley. Calculated the number and size of idlers required and selected the standard sizes for carrying and return

idlers. Selected the drive system based on the load capacity and pulley dimensions. Calculated the different resistive

forces acting on the conveyor and also designed the takeup pulley and counter weights to maintain tension in the belt.

Designed the frame to support the structure.

Conveyor assembly drawing

Conveyor Part Drawings

FMEA on the system

Conclusions:

Designed a standard trough belt conveyor system for a coal handling plant.

Performed Failure Mode Effects Analysis (FMEA) on the system.

10. Modeling, Simulating & Controlling a Servo Motor using LabView (Fall 2013, University at Buffalo)

Aim: To simulate the mathematical model of servo motor and compare it with an actual motor. To control the motor.

Implementation: Simulated mathematical model of servo motor from derived transfer function and studied the results for

different frequencies, keeping the amplitude constant. Compared the input voltage/signal, simulated model position and

actual motor position. Found proportional and derivative gains to meet design specifications and verified these results in

Simulink; simulated this PD controller and implemented the controller to evaluate its performance.

Main VI to control the simulated motor

Conclusions:

Succesfully simulated the mathematical model of motor and compared it with the actual motor position and the

reference signal.

Found the PD gains according to the design specifications and implemented this controller. Using the PD

controller, these three signals overlap as the derivative action produces faster response and so simulated and

actual motor positions match with the reference signal.

11. Miscellaneous

3D Model of a rim and a tire

Planetery Gear Drive

Components of IC Engine

Random Model Bracket