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Mechanical System Design, or ME 329, is a Cal Poly class in which students learn to design mechanical systems using machine elements such as threaded fasteners, power screws, springs, gears, bearings, and clutches. The course emphasizes decision-making based on technical and economic feasibility, integrating concepts from material mechanics, statics, dynamics, and design for strength and stiffness. This class has been particularly meaningful to me, as the projects I completed closely align with the type of design work I aim to pursue professionally. These projects involved using a computer-aided engineering (CAE) tool, such as MATLAB, to develop a program that allows an engineer to quickly iterate and finalize a design. On this page, I will present the design requirements and project reports that showcase my work from the course.Â
Mechanical System Design, or ME 329, is a Cal Poly class in which students learn to design mechanical systems using machine elements such as threaded fasteners, power screws, springs, gears, bearings, and clutches. The course emphasizes decision-making based on technical and economic feasibility, integrating concepts from material mechanics, statics, dynamics, and design for strength and stiffness. This class has been particularly meaningful to me, as the projects I completed closely align with the type of design work I aim to pursue professionally. These projects involved using a computer-aided engineering (CAE) tool, such as MATLAB, to develop a program that allows an engineer to quickly iterate and finalize a design. On this page, I will present the design requirements and project reports that showcase my work from the course.Â
Turbine Shaft System Design
Turbine Shaft System Design
Design Rationale
Design Rationale
"Wind energy is a growing industry. It is very exciting as offshore wind leases were sold for off the Morro Bay coast. Recently, turbines in Lompoc, just south of us, started generating energy. Cal Poly offers a wind energy tech elective and has a research turbine located on university lands east of the Dairy Creek golf course. A wind turbine is a classic machine system that incorporates many elements directly aligned with the curriculum of this course. " (Taken from Lab #2 – Turbine Shaft System Design, ME 329 Mechanical System Design, Dr. Joseph Mello, Cal Poly)Â
Design Requirements
Design Requirements
Size the stainless steel shaft and determine design details
Select and size bearings
Select a concept commercial coupling for generator attachment
Complete the shaft design by “fitting” components to the shaft and communicate the design details in a drawing suitable for a design review
Design Specifications
Design Specifications
Shaft Material Properties
Material: CRES 303
Yield Strength (Sy): 35,000 psi
Ultimate Strength (Su): 60,000 psi
Estimated un-modified endurance limit: Se' = 0.35 * Su
Design Speed and Loads
Nominal Operation Speed: 230 rpm
High Wind Cut-Off Speed: 300 rpm
Mean Torque on Shaft (Tm): 4,800 lb-in
Alternating Torque on Shaft (Ta): 2,400 lb-in
Constant Vertical Gravity Load on Blade Rotor (Fr): 160 lb
Constant Vertical Gravity Load on Brake Rotor (Fb): 20 lb
Constant Thrust (Shaft Axial Load): 500 lb
Torque and bending stress fluctuations are conservatively assumed to be in phase
Geometric and Manufacturing Data
Shaft Length: 12 inches between bearings
Distance from Front Bearing Center to Blade Rotor Centerline: 14 inches
Shaft Diameter: 40 mm at generator input end
Key Width: 12 mm to match the generator
Use metric bore bearings for design due to availability
Desired System Life
Shaft Reliability: 99% with a safety factor (SF) of 1.50 for infinite life
Bearing Design Life:
6 hrs/day generation
100 generating days/year
10 years at nominal speed
95% reliability per bearing
Final Design Report
Final Design Report
ME329-ShaftDesign-final.pdfMachine System Drive Concept Design
Machine System Drive Concept Design
Design Objective
Design Objective
"Design the power transmission system to drive the conveyor shown schematically below. The primary objectives of this lab are to:
Select a gear motor
Determine the power transmission drive ratio
Choose a timing belt that meets the desired system performance
The key performance parameters are achieving a target top speed and minimizing machine acceleration or time-to-speed (TTS).Â
 (Taken from Lab #3 – Machine System Drive Concept Design, ME 329 Mechanical System Design, Dr. Joseph Mello, Cal Poly)Â
Design Requirements
Design Requirements
Select a standard electric gear motor ratio/size and timing belt ratio to meet the top speed and acceleration (TTS) requirements
Research concept belt systems
Research possible gear motors
Design Data
Design Data
Total package weight on the conveyor: 325 lbf
Belt friction (static and kinetic): 0.30
Conveyor belt roller radius: 3.0 inches
Total conveyor roller/shaft inertia: 40 lbf·sec²/in
Conveyor target nominal speed (4% tolerance): 470 fpm
Conveyor time-to-speed (TTS) (maximum): 2.85 seconds
Additional Design Data
Additional Design Data
Motor type: Pole AC Induction Motor with a theoretical synchronous speed of 1800 rpm:
Note: 94% of synchronous or a 1690 rpm rated speed corresponds to the full load torque.Â
Typical motor sizes and rotor inertias:
Final Design Report
Final Design Report
ConveyorSystem.pdfPiping Flange Assembly Design
Piping Flange Assembly Design
Motivation and Objective
Motivation and Objective
Safe, high-pressure flange joints are a necessity in many ME industries.
The objective of this lab is to develop a CAE tool for designing the flanged joint concept shown below, which can be applied in high-pressure piping systems.
Design Requirements
Design Requirements
Maximum Expected Operating Pressure (MEOP): 5,000 psi
Minimum Safety Factors:
Yield: 1.25
Ultimate: 1.50
Bolt fatigue: 1.50
Proof Pressure: 1.25 * MEOP (not "person" rated)
Tube ID: 1.24 inches
Flange and piping material: 304 Stainless Steel
Sy = 35 ksi
Su = 85 ksi
Use NAS/MS 12-point A286 material fasteners:
Sp = 132 ksi
Sy = 155 ksi
Su = 180 ksi
Required CAE Tool Features
Required CAE Tool Features
Tube wall thickness sizing away from the joint (for yield and ultimate only)
Specify the flange geometry (diameter and thickness)
Specify the size and number of fasteners and bolt circle
Include a seal compressive zone check using an equation or plotting routine
Define the seal feature "E-Seal" flange gland dimensions
Specify assembly torque/lube settings and conditions to achieve the desired preload
Check fastener sizing for preload, proof pressure, and MEOP fatigue cycles (infinite life design—focus only on bolts, not flange or piping)
Perform leak or flange separation check with safety factor
Ensure socket or wrench assembly clearance
Final Design Report
Final Design Report
FlangedJoint.pdfMachinery System Spring Design
Machinery System Spring Design
Design Objective
Design Objective
Design a spring for a cam lobe and flat tappet follower used to create oscillatory motion for use in a manufacturing machine.
The machine is similar to the below image, though will be used in the horizontal plane.
Design Specifications and Requirements
Design Specifications and Requirements
Specifications
Specifications
Cam rotation frequency: 10 Hz
Follower and oscillating component mass: 9 kg
Total lift of oscillating components: 20 mm
Minimum spring ID: 25 mm
Maximum spring OD: 50 mm
Maximum spring free-length: 75 mm
Spring material: ASTM A-228 wire
Requirements
Requirements
The follower must remain in contact with the cam
For infinite life, design the spring's:
OD
ID
# of coils
Solid length
Free length
Final Design Report
Final Design Report
SpringDesign.pdfPage updated
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