I'm Hira Polat, an M.Eng. Automotive Engineering student at the University of Michigan. With three years of experience across student engineering teams and two industry internships, my main focus is electrified powertrains and battery technologies for EVs, covering everything from cell chemistry and pack architecture to structural design and performance characterization (SOC, SOH, charge discharge curves). That focus took me from leading battery systems on a world record breaking human powered vehicle to sizing high voltage accumulators for Formula SAE, and now continues at Michigan through Solar Car and MRacing. I'm most at home somewhere between a CAD assembly and an FEA solver, and I'm looking for what's next in EV battery engineering.
Quality & Manufacturing Engineering Intern at Parsan
Improved inspection throughput 10% on a 2M+ parts/year production line
Graduated B.Sc. in Automotive Engineering, Politecnico di Torino in 3 years
GPA 97/110, ranked 1st on Italy's national engineering entrance exam
Presenting Policumbent's world-record vehicle prototype (Cerberus)
Battery Lead behind 3 consecutive IHPVA World Records
Set in Nevada on Sep 12, 2024, the fastest arm-powered vehicle record.
Set at Balocco on Oct 18, 2025, as part of Cerberus's arm-powered record run.
IHPVA World 10 km Record — 13:56.94
Set at Balocco on May 23, 2026, completing Cerberus's third consecutive world record.
Since joining Policumbent in November 2023, I have contributed to three consecutive IHPVA World Records set by the Cerberus prototype, spanning the Speed, Hour, and 10 km categories. On Cerberus, my work included chassis FEM analysis, composite lamination of the wheel hubs, and supporting CAD designs.
The team's newest prototype, Pegasus, shifts from arm-powered to leg-powered propulsion with the goal of reaching 150 km/h and breaking the unfaired Land Speed Record of 144.17 km/h. On Pegasus, I designed and machined the fork components (CAD) for the driving wheel and ran topology optimization on structural parts to reduce weight while maintaining safety margins. In parallel, I led battery pack architecture and cell chemistry decisions across the team's platforms. Each of these contributions is detailed in the project sections below.
Designed a 12V LiFePO4 battery pack to power Pegasus's onboard electronics
Powered gearbox controllers (Omero/Vertigo), position-feedback board (Refuso), telemetry, and vision system
Benchmarked 26650 and 18650 LFP cell formats against capacity, discharge current, and cost
Selected a 4S configuration to reach the required 12V nominal output (3.4 x 4)
Split power into a 2S pack for Telemetry/Whereami and a 4S pack for Omero/Vertigo/Refuso to isolate sensitive signals from motor circuits
Modeled the pack enclosure in Siemens NX
Kept telemetry and GNSS signal cabling electrically isolated from high-current gearbox circuits
Reduced electromagnetic interference risk across the CAN bus network
Balanced capacity, discharge rate, and cost in the final cell choice
Optimized the fork joint (steering-to-fork connector) for Pegasus, designed for SLM 3D printing
Reduced part mass while maintaining structural safety under load
Defined design space in SolidWorks and ran topology optimization in Altair Inspire
Switched material from Al7075-T6 to AlSi10Mg (SLM-compatible)
Validated with FEM under a 1000N load, simulating full rider + prototype weight
Cut mass from 216.3g to 59.79g, a 72.36% reduction
Maintained a safety factor above 1.5 with stresses well below yield strength
3D-printed a prototype for fit-checks prior to SLM production
Investigated materials engineering strategies to improve lithium-ion battery cold-weather performance and thermal safety
Compared advanced LFP/carbon strategies against solid-state batteries (SSBs) as a long-term alternative
Analyzed particle size reduction and purity control effects on Li-ion diffusion path and capacity retention at sub-zero temperatures
Evaluated Super P carbon coating via mechanofusion on LFP cathodes, assessing rate capability, cycle life, and thermal runaway margin
Conducted a comparative Arrhenius-based analysis of ionic conductivity between liquid electrolytes and solid-state electrolytes (sulfide, oxide, polymer) across temperature
Purity control drove a 43.9% capacity gain at −20°C, confirmed in 18650 cells
Optimal carbon coating gave a 58.2% capacity gain at −10°C and raised the TR trigger temperature by +43°C
Combined strategy reached ~3x baseline capacity at −20°C
Concluded LFP/carbon is the strongest near-term path; SSBs remain the long-term solution pending cold-conductivity breakthroughs
Located the most critical stress location in a bicycle rear-hub assembly (drive-side female thread run-out)
Evaluated static and fatigue safety factors, and predicted fatigue life, under combined axial, bending, and torsional loads
Note: analysis performed using AISI 4130 steel properties as an academic substitute; the actual hub material is typically Ergal (7075-T6 aluminum)
Built a free-body diagram to extract axial force, bending moment, and torque at the critical section
Calculated static von Mises stress and safety factor (FoS = 3.33) using stress concentration factors
Ran fatigue analysis: computed corrected endurance limit, Goodman safety factor (nf = 4.72), and predicted life (~5.9×10^10 cycles, infinite life)
Validated hand calculations with FEA stress mapping
Redesigned the critical region (shortened bearing overhang, added fillet/relief at thread run-out, increased thread root diameter, specified rolled threads + shot-peening)
Recalculated stresses and safety factors on the redesign
Improved static safety factor from 3.33 to 5.63 (+69%)
Improved fatigue safety factor from 4.72 to 8.14 (+72%)
Reduced bending moment at the critical notch by ~25% and lowered stress concentration factors (Kt: 2.3→1.7, Kts: 2.0→1.6)
Raised corrected endurance limit from 31.8 to 37 ksi through surface treatment improvements
Built a complete equivalent circuit (OCV-R) model for an NMC 18650 cell: current integration, SOC tracking, and terminal voltage prediction
Characterized voltage behavior across three C-rates, a pulse current profile, and three constant-power discharge levels
Built in overcharge/overdischarge protection logic that halts the model when safety bounds are violated
Implemented the model in MATLAB/Simulink as dz/dt = -I/Qmax with Vt = OCV(z) - IR, using Qmax = 5.2 Ah, R = 0.009 Ω
Added overcharge (>3.6V) and overdischarge (<3.15V) cutoffs wired through comparator logic to a stop condition
Simulated constant-current discharge at 0.4C, 1C, and 2C to isolate the resistive (IR) contribution from the SOC-dependent OCV baseline
Simulated a repeating pulse current profile (5A charge / 1A discharge, 20s each, from SOC = 0.5) to capture transient voltage response
Derived discharge current as a function of demanded power and terminal voltage by solving P = I·Vt as a quadratic in I
Implemented the power-driven current relationship in Simulink so current self-adjusts as terminal voltage sags, then simulated constant-power discharge at 5W, 15W, and 25W
Delivered a working OCV-R model validated across constant-current, pulse, and constant-power operating modes
Discharge time scales inversely with C-rate, from roughly 9000s at 0.4C to roughly 1800s at 2C, with proportionally larger voltage sag at higher rates
Cleanly separated the resistive voltage drop from the OCV baseline, both in steady discharge and under pulsed loading
Derived and implemented I = [OCV(z) − √(OCV(z)² − 4RP)] / (2R) for constant-power discharge
Higher power levels reach the voltage cutoff far sooner: roughly 2300s at 25W vs. roughly 12500s at 5W
Designed a complete constant-mesh transmission system: helical gear train, intermediate shaft, and bearings
Specified all components to safely transmit 6 hp at 1,750 rpm input speed across multiple gear ratios
Built the full gear-mesh, shaft, and bearing analysis in MATLAB, solving stress, deflection, and fatigue equations programmatically
Solved gear mesh geometry (pitch, pressure angle, helix angle) and calculated bending/contact stress factors of safety for all six gears using AGMA methods
Modeled the intermediate shaft under combined bending, torsion, and thrust loads from helical gear forces, evaluated for both possible engaged gear-pair conditions
Performed static and fatigue failure analysis, deflection checks, and critical speed analysis on the shaft
Selected commercial ball bearings (sealed R12-series) and other real components by cross-referencing U.S. supplier catalogs, sourcing exact part numbers and links
Delivered a fully specified transmission design meeting all strength, deflection, and fatigue safety requirements across both gear-engagement scenarios
Selected bearings that minimized shaft span and bending moment while maintaining adequate load capacity
Produced a complete, sourceable bill of components with direct links to U.S. supplier catalogs, ready for procurement
Ran FEM analysis on the Cerberus chassis as a sandwich carbon-PVC composite structure under pedaling loads
Assessed composite ply failure risk across the frame's carbon fiber layup
Applied pedaling load case to simulate real riding conditions in Hypermesh
Evaluated results using the Tsai-Wu failure criterion for maximum ply failure across the composite layup
Maximum composite failure index reached 2.126E-02, far below the 1.0 failure threshold, indicating a large safety margin
Confirmed the chassis layup safely withstands combined bending-axial-torsion pedaling loads without static ply failure
Validated structural integrity ahead of Cerberus's world-record attempts
Laminated the wheel hubs in carbon fiber for Cerberus, following composite manufacturing standards
Ensured consistent fiber orientation and resin distribution for structural strength
Cut and laid up carbon fiber plies onto the hub mold according to the specified layup sequence
Applied vacuum bagging over the laminate to compact plies and remove trapped air and excess resin
Cured the part under vacuum, monitoring resin flow through the bagging film
Wore respiratory protection (mask) to safely handle resin fumes during the process
Produced lightweight, structurally sound wheel hubs used on Cerberus during its world-record attempts
Ensured consistent lamination quality through controlled vacuum-assisted resin removal
Designed the front fork assembly connecting to the driving wheel of Pegasus
CAD-modeled and assembled the full fork sub-system in SolidWorks
Produced the 2D drawing with GD&T for the fork-to-hub joint for production
Modeled structural parts (clamps, brackets, steering knuckle, column) in Ergal (7075 Al-alloy) for strength, and the handlebar in carbon fiber for weight savings
Assembled all parts, checking fit and interference between components
Generated orthographic views, sections, and GD&T callouts (flatness, parallelism, profile tolerances) per ISO 2768-mK and ISO 8015
Delivered an assembly-ready fork combining high-strength Ergal and lightweight carbon components
Produced a fully toleranced, manufacturing-ready drawing ensuring proper fit with adjoining components
Provided the mechanical basis for further structural validation (FEM/topology optimization)
Quantified how four heat treatments (normalize, water quench, oil quench, quench + temper) shift the hardness–toughness–strength trade-off in AISI 1045 CD steel
Verified the tensile fixture's bolts were safe at the machine's maximum load
Prepared and stamped dog-bone and Charpy specimens, austenitized at 850 °C, then cooled by the assigned route
Ran Rockwell C hardness (3 indentations per specimen), Charpy impact, and tensile-to-failure testing; pooled results across all lab groups to compare treatments
Calculated bolt shear and bearing safety factors using Von Mises, with Tresca as a conservative check
Mapped the trade-off: water quench 50 HRC / 2.2 ft·lbf / 0.8% elongation; normalizing 16 HRC / 35.6 ft·lbf / 7%
Identified quench + temper as the best operating point, 37 HRC with 18.4 ft·lbf and 175 kpsi UTS
Flagged an anomaly: oil-quenched UTS (180 kpsi) exceeded water-quenched (85 kpsi), likely quench-induced defects causing early brittle fracture
Fixture bolts ran at a shear safety factor of 1.008, effectively at the material's shear limit
Performed Brinell hardness testing on forged parts before machining, including a train piston head and a crank-shaft as part of post-forging property verification
Confirmed the forging + controlled cooling cycle delivered the hardness specified for the grade, and that the part was within the machinable window
Took multiple indentations across the cut face (crown toward hub) to check through-section uniformity rather than a single spot reading
Measured indentation diameters and converted to HB, logging each location
Compared readings against the grade's specified hardness band from the material data sheet
Piston head measured 262–284 HB across five positions (mean ≈ 271 HB), well inside spec and tight enough to indicate uniform cooling with no soft or over-hardened zones
Cleared the part for machining, avoiding downstream tool wear from an over-hard forging
Linked hardness back to approximate tensile strength (~900–950 MPa) as a quick property check before destructive testing
Ran FEM analysis on the Cerberus chassis as a sandwich carbon-PVC composite structure under pedaling loads
Assessed composite ply failure risk across the frame's carbon fiber layup
Applied pedaling load case to simulate real riding conditions in Hypermesh
Evaluated results using the Tsai-Wu failure criterion for maximum ply failure across the composite layup
Maximum composite failure index reached 2.126E-02, far below the 1.0 failure threshold, indicating a large safety margin
Confirmed the chassis layup safely withstands combined bending-axial-torsion pedaling loads without static ply failure
Validated structural integrity ahead of Cerberus's world-record attempts
Designed and manufactured a three-part cast aluminum hog assembly (hog, acrylic base, screw) as a personalized keepsake
Applied full GD&T control across the assembly to ensure proper fit and function
Modeled the assembly in SolidWorks and produced 2D drawings with dimensional and geometric tolerances
Cast the hog in 356 aluminum, then applied a T5 heat treatment (440°F for 6 hours, air-cooled) to increase hardness and strength
CNC-milled, turned, and laser-cut the base, screw, and acrylic plaque
Performed tolerance stack-up analysis to confirm secure fit and assembly
Delivered a fully assembled, functional cast aluminum hog trophy meeting all specified GD&T requirements
Demonstrated integration of four distinct manufacturing processes (casting, CNC milling, CNC turning, laser cutting) into one cohesive assembly
Validated that base thickness, hole location, and thread engagement provided secure mechanical assembly and consistent part-to-part fit
Simulated open-die upsetting of a cylindrical billet using QForm forging simulation software
Analyzed stress distribution and barreling behavior during compression
Modeled the billet and die geometry in QForm and ran the compression simulation
Tracked mean stress evolution and barreling as the billet deformed between the dies
Captured the classic barreling pattern expected in frictional upsetting
Validated peak stress concentration at the billet's equatorial bulge, consistent with forging theory
Completed simulation with full solver convergence
Designed the closed-die forging cavity for a 42CrMo4 steel connecting rod, including flash and gutter geometry
Modeled the finished part in SolidWorks, then applied machining allowances and thermal shrinkage to derive cavity dimensions
Designed the full cavity cross-section (land, flash, gutter) with fillet/draft callouts, breaking it into discrete volumes (V1-V7) for load calculations
Delivered a complete, dimensioned die cavity design ready to guide die manufacturing
Defined a 238.5mm cavity length (with flash/gutter) from a 186.5mm net forged part length
Established a repeatable allowance and shrinkage methodology for part-to-cavity dimensioning
Learned fluorescent magnetic particle inspection (MPI) to detect cracks on forged transmission components
Performed dimensional inspection of finished shafts against engineering drawings
Applied fluorescent magnetic solution and inspected parts under UV light, where crack indications glow due to magnetic flux leakage
Flagged forged shafts showing crack indications before further processing
Measured critical dimensions with a height gauge and cross-checked against GD&T callouts on the drawing
Gained hands-on exposure to NDT crack-detection methods used in OEM quality control
Helped prevent defective forged parts from advancing in production
Practiced linking dimensional measurements to GD&T requirements on real production drawings