Portfoilo-mechanical-engineering-design.pdf
- 1. Mechanical Engineering Design Portfolio Subash Pradhan Master of Mechanical Engineering, Lamar University Beaumont, Texas, 77705 Email:soobash191@gmail.com
- 2. Mode Shapes of Cantilever and simply supported beam using analytical and numerical approach (with 1D, 2D and 3D elements) Objective: Performed a modal analysis of Euler-Bernoulli’s beam using different element types (1D, 2D, and 3D) to study transverse vibration modes under cantilever and simply supported boundary conditions. Beam Model: Dimensions of 4.5 m x 0.4 m x 0.4 m. Material: aluminum for the cantilever and stainless steel for the simply supported beam. Modal Analysis: Conducted using ANSYS to determine natural frequencies and mode shapes. Theoretical frequencies were derived from beam theory for comparison. Boundary conditions: cantilever and simply supported beam Results:- -Modal frequencies were calculated analytically and compared with the numerical results obtained. Also, the participations factors were obtained. -Cantilever Beam: ANSYS results closely matched theoretical frequencies, with 3D elements showing the highest participation factor. -Simply Supported Beam: Minor discrepancies between simulation and theory, with better results from 3D elements.
- 3. Design and dynamic analysis of the electronic packaging using Ansys Fig: Mode shapes Objective: Design and analyse the mechanical integrity of an electronic assembly on a PCB, focusing on vibration effects and stress distribution in solder joints to ensure durability and reliability. Role:- Lead CAD modelling and FEA simulation and validation of results. Tool:-Ansys Actions:- -Performed modal analysis to identify natural frequencies around 128 Hz, 307 Hz, 474 Hz and 556.32 Hz corresponding to their first 6 mode shapes. -Conducted harmonic analysis in the range of 50-1000 Hz and obtained the frequency response (acceleration) plot, revealing critical resonance at 128 Hz. Fig: Frequency response plot -Modeled solder joints under mechanical loading to evaluate stress distribution, with maximum stress of 34734 MPa identified. -Recommended using SAC105 alloy for improved strength (up to 120 MPa) and redesigned joints to reduce stress concentration. Results:- -Identified the critical areas of stress concentration especially for solder (found to be higher for 4 corner solders in corner sections) -Enhanced solder joint reliability by switching to SAC105 alloy, increasing strength by 33% and reducing fatigue risk.
- 4. Vibration Testing (Sine Sweep Testing and Random Vibration Testing) Fig: Sine sweep testing and the frequency response plot of the DUT (here Ch1 is the input signal and ch2 is the response) Fig: Electrodynamic Shaker (Crystal Instruments) Fig: Device Under Test Fig:Modal Shaker Fig: random vibration testing Task: Design and execute a testing framework using industry-standard equipment and methodologies to conduct sine sweep and random vibration testing Action: Set up the testing environment with an Electrodynamic Shaker and accelerometer sensor to measure precise vibration responses. Tools/Software: Uniaxial accelerometer sensors, Crystal Instrument Electrodynamic shaker, CI control software, CI data acquisition system, MTS Modal shaker Sine Sweep Testing: --Monitored amplitude and phase response curves in real-time, analyzing peaks in the frequency response graph to locate natural frequencies. Random Vibration Testing: --Simulated real-world vibrational conditions by applying a randomized input signal across a defined frequency spectrum. --Observed time-domain response and tracked parameters like RMS peak acceleration (0.5998 g), frequency distribution, transmissibility and elapsed cycles. --Adjusted test parameters iteratively to ensure accurate data acquisition and compliance with testing standards. Conclusion: Identified key resonance frequencies and critical dynamic behavior of the module, providing actionable insights for design optimization.
- 5. Design and analysis of fixture for vibration testing Fig: Drawing and CAD model of final fixture design Situation:- -Tasked with designing a test fixture for an event recorder (Black-Box) to ensure it remained stable during vibration testing and maintained its specified orientation. -Required to avoid fixture resonance below 1200 Hz and ensure minimal transmissibility. Actions:- -Developed multiple CAD models using SOLIDWORKS, iterating on design by adding ribs and stiffeners for dynamic performance improvement. -Performed modal analysis using Ansys to ensure natural frequency exceeded 1200 Hz. -Conducted harmonic analysis to validate fixture's vibration response with mounted UUT. -Applied GD&T principles to the mounting holes, surfaces, and interfaces to ensure correct assembly and fixture performance under vibration condition and created 2D drawings for the final model. -3D model of fixture along with attached UUT was developed and analyzed using Ansys for further validation of the design. Results:- -Fixture design met all vibration test specifications, including first natural frequency exceeding 1200 Hz, ensuring no interaction and no resonance. -Results confirmed the fixture's capability to support accurate vibration testing for critical components. Table: Modal analysis results Fig: Final CAD model of the designed fixture Fig: 1st, 2nd and 3rd mode shape of the designed ficture
- 6. Bolted Joint Analysis in Ansys Fig: CAD model of pipe flange and bolt assembly (up) and deformational plots for bonded and frictional contacts (down) Objective: To analyze the stress distribution across the bolted joints and flange, ensure structural integrity under operational loads, and assess the effect of bolt pretension and friction at the contact surfaces. Actions:- -created a detailed 3D model using SOLIDWORKS of the flanged pipe assembly, including bolts, flanges, and pipe segments. -Defined frictional contacts at critical interfaces to accurately capture the interaction between bolts and flanges. -Applied bolt pretension to replicate initial bolt tightening, and external loads (e.g., internal pressure, external forces) were applied to the assembly. Fig: stress plot for bolts and flange assembly and the contact status plot -Used Ansys to conduct a static structural analysis, solving for stress, strain, and deformation and obtained mesh independent results. -Applied boundary conditions, pretension in the bolts, and external loads (internal pressure and external forces) to simulate operational scenarios. Outcomes:- -Status of different contacts was demonstrated using Contact Tool for further validation of results -Maximum von Mises stress was found to be around 237 MPa, which was below the material's yield strength confirming the design’s safety. -Stress concentrations around bolt holes were identified and deemed acceptable, with recommendations for increasing the bolt diameter to improve load distribution
- 7. Dynamic analysis of 5 MW NREL Wind turbine to understand failures in wind turbine blades Objective: Conduct CAD modeling, modal, harmonic, and random vibration analysis on a turbine rotor to assess dynamic behavior. Turbine Specifications: (NREL , 5MW) Blade length: 28 m, Hub diameter: 4.2 m, Rated wind speed: 11 m/s, Startup wind speed: 3 m/s. RPM at rated power: 800 RPM, Survival wind speed: 45 m/s, Furling method: Spring/hinge tilt-up. Modal Analysis:- -Determined natural frequencies and obtained mode shapes in edgewise & flapwise directions -identified critical speed at 2.2973 rad/s.Performed single-blade modal analysis for operational speeds (1-5 rad/s) and created a Campbell diagram. Fig: Campbell Diagram Harmonic Analysis:- -Analyzed turbine response in edgewise (X-direction) and flapwise (Z-direction), identifying harmful resonant frequencies at 3.72 Hz, 59.62 Hz (edgewise), and 1.10 Hz, 4.11 Hz, 58.32 Hz (flapwise). Random Vibration Analysis: Evaluated turbine blade response to random vibrations using PSD displacement data. Key Findings: Identified critical speeds and resonant frequencies to avoid, and demonstrated the effectiveness of tip mass in vibration suppression Fig: Frequency response plot (acceleration) for edgewise and flap-wise excitation(top & bottom resp) Fig: Model with added tip mass Fig: 1st, 2nd and 3rd modeshape Fig: Frequency Response (random vibration) Fig:PSD input
- 8. Structural Design and Fluid flow analysis of Penstock Bifurcation Fig: drawing for bifurcations and welding sequences Project: Hydraulic and Mechanical design of Penstock Bifurcation Role: Mechanical Design Engineer, Entegra Sources Pvt Ltd Objective: Design the penstock bifurcation to withstand dynamic pressure changes caused by water hammer effects due to sudden valve closures. Actions:- 1)Hydraulic Design: Designed the bifurcation to handle a gross head of 362.29 m and included surge head for transient pressures; || Modeled the bifurcation for an even flow split between two outlets (Outlet 1: 452.86 m³/s, Outlet 2: 5800 kg/s).’ || Accounted for the water hammer effect from sudden valve closures, ensuring the design withstood maximum internal pressures. Fig: Deformation and Von-Misses plot of different bifurcation designs 2)Structural Analysis: Calculated allowable stresses using ASCE standards based on yield and tensile strength; || Identified critical stress zones and optimized the design to ensure stresses remained within safe limits || Addressed local membrane stresses at geometric discontinuities, allowing up to 1.5 times general stress limits. 3) Design Optimization: Set shell thickness to 48 mm, considering dynamic load conditions || Added sickle plates, C-rings, and stiffeners to reduce stress concentrations and improve structural integrity. Conclusion:- The final design (Option 4), including the sickle plate, C-rings, stiffeners, and flanges, provided the best balance between stress reduction, structural reinforcement, and efficient flow division. with maximum deformation reduced to 0.356 mm Fig: velocity and streamline lot
- 9. CFD analysis of 2D incompressible flow using MATLAB and OpenFOAM Objective: Objective: Simulate incompressible fluid flow using Navier-Stokes and continuity equations ,solving for velocity and pressure fields using MATLAB and OpenFOAM. Actions- -Implemented FDM approach in Matlab with a staggered grid to solve the velocity & pressure fields. -Used Predictor-Corrector method for iterative updates of fluid properties. -Applied no-slip boundary conditions and inlet velocity of 2 m/s. -Applied PISO algorithm using the finite volume method for solving the flow equations in OpenFOAM. -Simulated incompressible fluid flow and visualized results using ParaView. Results:- -MATLAB: Showed parabolic type velocity profiles and consistent pressure gradients, confirming correct boundary conditions. -OpenFOAM: Produced detailed velocity and pressure fields, closely matching MATLAB results while providing better scalability for larger domains. Outcome:- -Demonstrated effective use of numerical methods for solving fluid dynamics problems. -Both methods confirmed accuracy of boundary conditions and provided insights into flow behavior and pressure variations. Predictor Pressure Poison Corrector
- 10. Design and Analysis sub-soil model and heat pipes using Ansys Fluent Objective : Tasked with designing and optimizing a geothermal heat exchanger system for a residential building at Beaumont, Texas, with a focus on improving thermal performance through pipe design. Actions:- -Created 2D/3D models in ANSYS and performed transient thermal analysis using Ansys FLuent. -Applied realistic temperature profiles (daily average temperature for 5 years) for Beaumont, with house temperature fixed at 25°C and sub-soil at 15°C at 10 m depth. -Conducted mesh refinement, grid and time-step independence check for accurate results. -- Investigated the impact of spacing (1m, 1.5m, 2m) and orientation (horizontal vs vertical) on heat transfer rates and thermal conductivity. -Analyzed the effect of different diameters (32mm, 50mm) on temperature distribution and heat transfer rate. Findings: -The heat flux is higher under the house in summer (6.866 W/m² vs. 5.849 W/m²), but lower in winter (1.917 W/m² vs. 3.419 W/m²). This suggests better thermal performance under the house in warmer months, but reduced efficiency in colder months due to a smaller temperature gradient. - Thermal performance is significantly influence by pipe distancing and position but further and more accurate and long-term simulation need to be conducted for more accurate4 results.
- 11. Advanced Heat transfer analysis through letter blocks using OpenFOAM Situation/Objective: To investigate heat transfer from a solid copper block (L,U,E,N shapes) maintained at 500°C) to ambient air (at 20°C) via forced convection. The goal is to compute the total heat transfer rate and the average heat transfer coefficient for each shape. Actions: Geometries: Simulated four shapes (L, U, E, N) to analyze heat transfer rates and coefficients. Mesh Setup: Created meshes with blockMeshDict, defined computational domain, and placed the copper block using createObstacle.set. Boundary Condition: Configured temperature, velocity, and turbulence parameters in Pressure, Velocity , K, epsilon, alphaT file Simulation Parameters: Ran simulations for Reynolds numbers 5,000 and 10,000, testing mesh sensitivity while configuring ControlDict File Findings: -Calculated heat transfer coefficients for each geometry, averaging -2.79 W/m²°C, with a 7.2% error compared to theoretical values. -The study demonstrated how different geometries and Reynolds numbers affect convective heat transfer, successfully simulating forced convection and validating the numerical approach against theoretical predictions using OpenFOAM.
- 12. Additive Manufacturing (FDM , fabrication, testing and numerical analysis) Objective:-a) To perform an experimental investigation and numerical analysis of ASTM standard additively manufactured specimen; b) To design an FDM printed bridge model and perform structural analysis and topology optimization. Methodology:- Specimen: Dog-bone shape (ASTM D638 Type I) designed in Autodesk Inventor. Materials & Printing: 1.75 mm PLA, ABS & TPU filaments, 0.4 mm nozzle on Prusa-i3; two specimens in each orientation (horizontal/vertical).; printed in horizontal and vertical orientation and different fill-pattern Testing: Tensile tests performed per ASTM D638; strain rate 5.1 mm/min. FEA: ANSYS Workbench for modeling stress and deformation. Result and Conclusion: -Vertical orientation showed higher deflection; slight variation in tensile strength by orientation. -Similar deformation (0.479 mm) and stress (57.49 MPa) for both orientations. -Build orientation affects tensile properties; horizontal and vertical orientations impact strength and deflection. Orientation must be considered in design for FDM 3D-printed PLA parts.
- 13. Non-destructive Testing (Ultrasonic Testing and Liquid Penetrant Testing) Fig: Pulse-Echo and Through Transmission Ultrasonic Testing Fig: Liquid Penetrant Testing and Visual Inspection Objective: Conduct Pulse-Echo and Through Transmission Ultrasonic Testing for crack detection. Materials/ Apparatus Used: Krautkramer USN 60 (Pulse-Echo), Proceq Ultrasonic Test Device (Through Transmission), Couplant (water), Calibration tools, Test specimens (Steel block, Concrete cylindrical block). Pulse-Echo Ultrasonic Testing:- Calibration: Using ultrasonic calibration block, velocity verified;|| Frequency: 5 MHz.; Measured Distance: 4 inches (thickness/crack location). Through Transmission Ultrasonic Testing:-Equipment: Proceq Ultrasonic Test Device.; Calibration: Velocity set to 4650 m/s.; Frequency: 40 kHz. Objective:To assess the surface integrity of an aerospace Aluminium component using Liquid Penetrant Testing (LPT) to detect any surface-breaking defects. Materials Used: A liquid penetrant (Spotcheck-dye penetrant and developer Actions: -The test was carried out as per ASTM E165 standard. -Cleaned the part to remove contaminants, then applied the dye penetrant and allowed it to dwell for 10 minutes and then developer was applied. Finding:- -Some cracks were visible throughout the thickness of the part,
- 14. PID Controller Design Objective: Design and simulate an active suspension system using MATLAB Simulink to improve vehicle ride comfort and stability. Simulation Parameters: Mass (Ms = 241.5 kg, Mu = 41.5 kg), spring constants (Ks = 6000 N/m, Kt = 14000 N/m), damping coefficients (bs = 300 Ns/m, bt = 1500 Ns/m). Input Parameters: Step input (0.1m) and sinusoidal input for system testing. Transfer Function: Derived transfer function for the system from input (ground vibration) to output (sprung mass displacement) using Simulink. Controller Design:Designed and implemented PID, P, PI, and PD controllers to optimize system performance.PID controller tuned with Kp = 10, Ki = 5, Kd = 400 to meet design specifications (overshoot < 40%, settling time < 5s). Simulation Results:- -Passive suspension system had overshoot of 63.1% and settling time of 7.07s. -PID controller reduced overshoot to 39.3% and settling time to 4.75s. -PD controller also achieved 39.3% overshoot, with similar performance to PID.
- 15. Design of Integrated Solar Power Systems Role:- Electro-mechanical Engineer || Sunbridge Solar Nepal Pvt Ltd || Kathmandu, Nepal Actions:- System Design and Engineering: -Designed Single Line Diagrams (SLDs) for efficient interconnection of solar panels, inverters, charge controllers, and batteries. -Performed load analysis and energy demand estimation using tools like PVsyst and HOMER for optimal solar array and battery sizing. Component Specification and Selection -Selected high-efficiency solar panels, MPPT/PWM inverters, fuses, breakers, surge protection devices and lithium-ion/lead-acid batteries for performance, durability, and cost efficiency. System Integration Integrated and configured solar components (panels, inverters, batteries) for optimal energy production and efficiency. || - Set up SCADA and IoT-based monitoring systems for real-time performance tracking and system optimisation. Installation, Commissioning and Performance Monitoring and Optimization -Conducted component testing (voltage, current) and full-system integration to verify performance. -Monitored system performance using IoT sensors and cloud tools for real-time data analysis. -Optimized inverter settings and charge controller configurations to improve system efficiency. -Diagnosed and resolved operational issues to ensure continuous, efficient performance.
- 16. Multistage Lift station projects Fig: layout, piping design, cable sizing for the solar lift project Role:- Electro-mechanical Engineer || Sunbridge Solar Nepal Pvt Ltd || Kathmandu, Nepal Projects:- Piluwakhola Solar Lift Project (60,000 KWP) AEPC; Saplakhola RSDWP (30, 000 KWP)- AEPC; Sunkoshi Solar Lift and Irrigation project – 4800 KWP, Nepal (AEPC) Actions:- 1. System Design and Selection: Perform demand and load calculations to assess power needs for solar-based systems (e.g., mini-grids, irrigation). || Design pump systems (AC, DC, submersible) based on hydraulic calculations and select pumps that match the required flow rates and head. 2. Component selection and Sizing: Select components like valves, flanges, surge protection devices, and cables based on system requirements, voltage, and environmental conditions. || Properly size cables for power transmission and select Variable Frequency Drives (VFDs) to optimize pump speed. Fig: Performance curves for selected pump and the design summary 3. Structural Design and Analysis: Design solar panel mounting structures and pipe support systems, ensuring they can withstand environmental conditions (e.g., wind, seismic activity) complying AEPC standards. 4. System Testing and Commissioning: Oversee pretesting of individual components (solar panels, inverters, pumps) to ensure they meet technical specifications. || Perform system integration testing and site verification to ensure proper operation after installation. 5. Troubleshoot, Maintenance and Optimization : Provide post-installation support, troubleshooting issues and ensuring the system operates efficiently. || Continuously monitor system performance, optimizing energy efficiency and pump operation. 6. research and Development: Conduct research to explore new materials, design techniques, and methodologies to reduce costs, improve system reliability, and develop innovative solutions for solar-powered water lifting systems.
- 17. Detailed Kinematic analysis of Theo-jansen Linkage and 4 bar mechanism (analytical approach and numerical approach) Project Title: Kinematic and Motion Analysis of Theo-Jansen Mechanism Situation: Analyzed and simulated the motion of the Theo-Jansen walking mechanism, using SolidWorks for CAD modeling and motion simulation, and MATLAB . Action: -Developed a CAD model in SolidWorks and conducted motion simulations to study angular displacement, velocity, and linear displacement. -Used MATLAB to generate a code for solving equations using Jacobian approach and plot the mechanism's path and position. -Solved vector loop equations in Mathcad for comparison and obtained various results across different tools. Result: -Generated and visualized kinematic data (e.g., angular displacement, linear velocity, power consumption) from both SolidWorks simulations and MATLAB analysis. -Achieved consistent results across all methods, demonstrating proficiency in using CAD and computational tools for motion and kinematic analysis.