How SDC Verifier Helped Rable Optimize Solar Panel Frames for Weak Roofs

Solar panel frames must withstand heavy loads like snow, wind, and weight. Without precise engineering, they risk failure, inefficiencies, and unnecessary material use — leading to higher costs and reduced durability.

To solve this, RABLE developed a lightweight mounting system that allows solar panels installed on weak industrial and commercial roofs. However, ensuring these frames were structurally sound required advanced engineering validation.

SDC Verifier provided a detailed analysis and optimization process, ensuring the frames met strict industry standards while using the least material possible.

About RABLE

RABLE is a Dutch company pioneering solar panel mounting solutions designed for flat roofs, including those with weak structural capacity. Founded in 2022, RABLE aims to maximize solar adoption by eliminating traditional installation barriers such as heavy ballast and costly roof reinforcements.

The Engineering Challenge

Solar panel frames must meet exacting standards to endure diverse environmental conditions without failure. The engineering challenges centered around compliance with industry standards, optimizing structural integrity, and minimizing material usage.

Meeting Industry Standards

To ensure reliability and safety, the project adhered to rigorous guidelines:

• EN 13001 (2018): Linear static stress checks to verify the structural strength of components under load.
• Eurocode3 Member Standards (EN1993-1-1, 2005): Beam member checks to evaluate stability.
• DNV Buckling Strength of Plated Structures (2010): Analysis of plate elements to prevent structural buckling under compressive force.

Diverse Load Cases

The designs were tested against multiple load scenarios to simulate real-world conditions, including:

• Self-weight and solar panel weight: Ensuring the frames could effectively bear their load.
• Snow load accumulation: Different accumulation coefficients (15, 20, 25, and 50 years) were applied for varying environmental conditions.

Optimizing for Efficiency

A critical goal was to achieve the necessary structural strength while minimizing material usage:

• Excess material increases costs and environmental impact.
• Under-designed frames risk failure, jeopardizing safety and functionality.

The engineering solution required precise modeling and iterative analysis to strike the perfect balance between durability and efficiency. By addressing these challenges, the team set the foundation for a design that met regulatory standards and aligned with cost-efficiency and sustainability goals.

The Solution with SDC Verifier

SDC Verifier provided a comprehensive solution using advanced analytical tools and methodologies to address the complex demands of solar panel frame optimization.

Development of Beam and Plate Models

The engineering process began with the creation of two complementary models:

• Beam Models: These were designed to evaluate the frames’ global structural behavior, including load distribution, stress analysis, and overall stability.

• Plate Models: Used for detailed analysis of critical areas prone to buckling, localized stresses, and individual elements such as rivets and pins, ensuring the frames meet safety and performance standards.

Image: Detailed model overview of the solar panel frame, showcasing the structure’s key sections for analysis.

Image: Close-up views of plate elements used in the frame design, highlighting the connections and structural details.

Image: Comparison of beam and plate models used for detailed analysis, highlighting their role in accurately calculating axial forces and improving design precision.

Optimization Across Multiple Cases

The designs were optimized by testing various configurations to identify the most efficient layout for load distribution. As the number of rows of solar panels increased, the load concentrated more heavily in the center supports, requiring precise optimization to ensure stability and durability.

Scenarios with 2 to 6 frames in the transversal direction were analyzed to determine the most efficient layout for load distribution.

Configurations with several frames in the longitudinal direction

To optimize the structural integrity and efficiency of the design, various scenarios were analyzed with different numbers of frames in both longitudinal and transversal directions. This approach ensured a comprehensive understanding of how frame placement affects load distribution and stability under real-world conditions.

Constraint Setup and Visualization

Visualization of frame constraints used for optimization.

Image: Constraint setup for Case 1, illustrating basic boundary conditions.

Image: Constraint setups for Cases 2-5, representing intermediate boundary conditions.

Image: Constraint setup for Case 6, highlighting free constrained side frames.

The team simulated a range of real-world scenarios by applying different boundary conditions in both longitudinal and transversal directions. These variations enabled the identification of optimal configurations for stability, weight efficiency, and performance under demanding conditions.

Stress level

The images below compare the initial design with the optimized design, highlighting the improvements achieved through structural analysis and refinement.

Initial design

The initial design revealed high-stress concentrations in critical areas, such as connections, joints, and support elements. These stress points indicated a risk of structural weakness, particularly under heavy loads like snow accumulation.

Highlighted Issues:

• High stress at frame intersections and rivet locations.
• Uneven load distribution, leading to localized weaknesses.
• Excess material use without proportional strength benefits.

Optimized design

Through iterative analysis and refinements, the optimized design redistributed forces more efficiently, significantly reducing stress concentrations in critical areas.

Key Improvements:

• Enhanced load distribution across the entire structure.
• Reduction of peak stress areas, lowering the risk of failure.
• Material optimization, maintaining strength while minimizing excess usage.

• Iterative Refinement:
  Each case was evaluated for structural integrity, balancing the trade-off between weight reduction and stability.

This process highlighted configurations that maximized stability while minimizing material use.

Image: Beam and plate models for various configurations, showcasing design optimization and structural analysis.

To ensure durability and safety, detailed axial force calculations were performed:

• Forces in rivets, pins, and bolts were analyzed under shear, axial, and bending loads.

The analysis focused on critical structural components, including rivets, pins, and plates, ensuring accurate stress and moment evaluations. Local coordinate systems were applied for precision, enabling insights into load behavior across connections.

Image: Analysis of rivets components under various load cases, highlighting local coordinate systems for precise force distribution.

Image: Rivets in the center of the frame analyzed for forces under different constraints and snow load conditions.

Image: Pin components subjected to axial and shear force analysis under diverse loading scenarios.

Each element in the frame design inherently features a local coordinate system, which is crucial for the precise evaluation of stresses and moments in critical joints and connections. This localized approach allowed for detailed axial, shear, and bending forces analysis, ensuring every component’s behavior was accurately modeled under various load conditions.

Upon completing the detailed axial force calculations, which confirmed the frame’s durability and safety, the project team turned its attention to further innovations. These advancements included:

• Lightweight Design: The system’s weight has been reduced by up to 25 kg/m², making it 50% lighter than conventional solutions.
• Efficient Load Distribution: Optimizing the structural layout to manage forces effectively across the frame.
• Lattice Technology: Tension cables are strategically placed to support distributed loads effectively over strong roof areas.
• Fully Recyclable & Locally Produced: Panels and structures made sustainably in the Netherlands, reducing CO₂ emissions.

By leveraging SDC Verifier’s capabilities, the team achieved optimized, durable, and standards-compliant solar panel frames, paving the way for efficient and reliable installations.

Results

The collaboration with SDC Verifier yielded precise, effective solutions for optimizing solar panel frames and addressing structural demands and industry requirements.

Image: linkedin.com/rable-solutions

Optimized Designs for Various Scenarios

Through comprehensive analysis, the project delivered tailored designs for multiple configurations:

• Tested and optimized for 2 to 6 center supports, ensuring flexibility to accommodate various installation needs.
• Refined designs that balance minimal material usage with maximum structural stability, reducing costs without compromising safety.

Visualization of Load Distribution and Axial Forces

Detailed simulations provided clear insights into the behavior of the frames under different loads:

• Load distribution maps highlighted stress points, enabling targeted reinforcement where needed.
• Axial force analysis was performed on all components of the beam model, including rivets, pins, and bolts. This ensured robust connections and compliance with Eurocode 3 standards to prevent potential failure under long-term loads.

Compliance with Industry Standards

All designs were rigorously tested and verified to meet critical regulatory standards:

• EN 13001 (2018): Ensuring stability under linear static loads.
• Eurocode3 (EN1993-1-1, 2005): Meeting structural requirements for beam elements.
• DNV Buckling Strength (2010): Addressing buckling risks in plated structures.

The final designs achieved the dual goals of structural efficiency and regulatory compliance, ensuring reliable performance and extended service life for solar panel installations.