📋 Case Study

Desert Valley 200MW Tracker Array Wind-Induced Torsional Failure Mitigation

Repeated torsional resonance at 0.8–1.2 Hz causing torque tube weld fatigue cracks after 18 months

🏗️ Project Overview

200MW utility-scale solar plant in Arizona desert with high diurnal wind gusts

🎯 Challenge

Repeated torsional resonance at 0.8–1.2 Hz causing torque tube weld fatigue cracks after 18 months

🔧 Design Approach

Redesigned support spacing from 12m to 8.5m; added tuned mass dampers (TMDs) at mid-span; upgraded tube wall thickness from 4.8mm to 6.4mm

📐 Design Diagram

AI-generated project design illustration

📐 Key Calculations

Natural Frequency Shift

f_n ∝ 1/L² × √(EI/GJ)

Result: 1.2 Hz → 2.1 Hz

Moved away from dominant wind energy band

TMD Tuning Ratio

ω_damp / ω_system

Result: 0.98

Optimal energy absorption at resonance peak

📊 Results

Zero torsional failures over 36-month post-remedy period; 92% reduction in strain amplitude at critical welds

💡 Lessons Learned

• •Field-measured wind spectra must drive modal analysis—not just code wind speed
• •TMD mass must be ≥1.5% of span mass for effective suppression

✅ Key Takeaways

• 1Field-measured wind spectra must drive modal analysis—not just code wind speed
• 2TMD mass must be ≥1.5% of span mass for effective suppression