Composite overwrapped pressure vessels (COPVs) – such as those used for hydrogen (H₂) storage and compressed natural gas (CNG) – are critical for clean energy and transportation. However, the high cost of carbon fiber and manufacturing means that reducing costs is a top priority for engineers and technical decision-makers in this sector. This article explores scientific and technical strategies to cut costs in COPV development and production, including simulation-driven laminate optimization, high-fidelity simulation to reduce physical testing, minimizing carbon fiber usage through better design (e.g. local dome reinforcements), early integration of automation and manufacturing considerations, resin uptake control in filament winding, and in-process quality monitoring (CWPWatch Technology). Throughout, we highlight how these approaches improve efficiency without compromising safety – and how a comprehensive engineering partner like CIKONI can support these endeavors from concept to production.
The Challenge: Cost and Complexity in Composite Pressure Tanks
Designing composite pressure tanks (Type III, IV, and upcoming Type V cylinders) is a complex balancing act. These composite materials systems must withstand extreme pressures (up to 700 bar for H₂, ~350 bar for CNG) while minimizing weight. Carbon fiber offers unparalleled strength-to-weight, enabling safe high-pressure storage. But carbon fiber is expensive, so using it efficiently is paramount. Moreover, the cylindrical geometry with dome ends, while simple-looking, involves complex fiber paths and anisotropic behavior. Small changes in fiber orientation or layer stacking can greatly affect performance. In fact, manufacturing-induced fiber misalignments or overlaps (e.g. in the dome) can significantly knock down the tank’s strength. Therefore, cost reduction must come from smarter design – using just enough material in the right places – and smarter processes that avoid waste and rework.
Key cost drivers for COPVs include the composite material itself, auxiliary components like On Tank Valves (OTV) and the development work, labor and cycle times for filament winding, and the number of prototype/test cycles required to qualify a design. Below we discuss strategies to tackle each of these cost factors:
- Advanced simulation and laminate optimization to minimize overdesign and material use while reducing development effort by identifying potential challenges early.
- Higher-fidelity simulations to reduce the number of physical test iterations.
- Advanced laminate design (e.g. local fiber placement in domes) to cut carbon fiber usage.
- Design for manufacturing and automation, implemented early, to streamline production.
- Process control (resin content, fiber alignment, gaps) to avoid inefficiencies that add weight to the pressure vessel.
- Quality monitoring to catch defects early and ensure consistency.
By addressing these areas, recent projects have shown double-digit percentage savings in material and improved performance. For example, CIKONI engineers integrated local dome reinforcements in an manufacturers vessel and optimizing the layup led to a 15% reduction in carbon fiber usage while actually increasing usable storage capacity by 17%. In the following sections, we delve into each strategy in detail.
Simulation-Driven Laminate Optimization
One of the most powerful tools for reducing COPV cost is FE simulation-driven design optimization. Instead of relying on trial-and-error physical prototypes, engineers use advanced finite element analysis (FEA) and optimization algorithms to fine-tune the composite laminate layup (the sequence and orientation of fiber layers) for minimal material usage while meeting all strength requirements. By iterating virtually, the design can be lightweighted without risking safety.
Modern composite simulation considers detailed failure criteria (e.g. progressive fiber/matrix failure modes) and can include optimization routines to automatically seek an optimal layer configuration. For instance, laminate optimization with physically based failure criteria allows finding the lightest combination of hoop and helical layers that still meets burst pressure targets. CIKONI’s engineering approach includes this kind of laminate design and optimization, leveraging both analytical and numerical methods. The result is a tailored layer structure for the tank’s cylindrical body and domes that uses material efficiently.
Critically, simulation-driven optimization is not done in isolation – it feeds on accurate material data and manufacturing knowledge. Engineers first create high-fidelity material models (“material cards”) from tests, capturing the anisotropic behavior of the carbon fiber composite. These models drive the FEA to predict stresses and strains in each layer and orientation. Then optimization algorithms adjust layer angles, thicknesses, and stacking sequence to reduce weight while maintaining a safety margin. Through this virtual process, multiple design iterations can be evaluated rapidly, something impractical if each iteration required winding and burst-testing a physical tank.
In addition to structural optimization, a critical advancement lies in the integration of winding simulation data into structural simulation. By transferring as-manufactured fiber orientations, overlaps, and potential gaps from process simulation into the mechanical model, engineers can better reflect real-world conditions. This coupling improves the accuracy of stress and failure predictions, particularly in critical regions like the dome. It also enables the identification of sensitivity zones where deviations from ideal fiber paths significantly impact performance. Such insights guide design and process refinements and help set realistic manufacturing strategies. CIKONI routinely leverages this data flow to bridge simulation and production, ensuring that optimized designs remain robust under actual manufacturing conditions.
In a recent collaborative project, this approach proved its value: CIKONI led the laminate design, simulation, and optimization for an improved H₂ tank concept, working through several virtual design iterations from winding simulation to structural assessment to find the optimal fiber layup. Only after simulation indicated the design met all criteria did the team proceed to manufacture and test – and they achieved the targets on the third iteration with minimal physical tweaking. Such simulation-driven workflows cut down the number of prototype cycles, directly reducing cost and development time and generating G-Code for the actual winding step.
High-Fidelity Simulation for Fewer Test Cycles – and More Demanding Load Cases
Increasing the accuracy of simulations is a powerful strategy to reduce both material costs and development time for composite pressure vessels. High-fidelity models allow engineers to reliably predict structural behavior, reducing the reliance on expensive and time-consuming physical testing. CIKONI has developed unique design and simulation capabilities in this field. This is particularly critical in safety-relevant applications like hydrogen storage, where tanks must withstand not only internal pressure but also external impacts, crashes, or ballistic threats. The better the simulation reflects reality, the fewer validation tests are needed — and the more robust the resulting design.
One major advancement in advanced simulation methods is the use of multiscale simulation for composite overwrapped pressure vessels (COPVs). In this approach, the material’s microstructure — including fiber, matrix, and interface behavior — is characterized at the mesoscale and fed into a macroscale tank model. This enables the finite element (FE) simulation to account for critical manufacturing effects such as fiber volume fraction gradients, resin-rich zones, and fiber overlaps and misalignments, especially in complex areas like the dome. Such detail enhances the precision of burst pressure and failure predictions, reducing the need for physical iteration.
An important enabler of this accuracy is compaction simulation, which models how fiber tows deform and consolidate during winding. This process helps derive realistic local fiber volume contents (FVF) across the vessel – capturing the effects of tow accumulation, inter-tow voids, and local thickening. Incorporating these FVF distributions into the structural simulation yields a more representative stiffness and strength profile of the actual laminate, leading to better predictions of failure modes and more trustworthy safety margins.
CIKONI integrates process simulation results — including fiber orientations, winding angles, overlaps, and gaps — directly into structural models. This data transfer allows as-manufactured geometries and deviations to be reflected in the simulation, closing the loop between design and production. As a result, the model doesn’t just represent a nominal ideal — it mirrors real tanks. This approach is especially valuable in assessing structural sensitivity to process variations, which helps define robust manufacturing tolerances without overconstraining production.
Beyond burst simulations, CIKONI extends its simulation capability to crash, impact, and ballistic events, including Burst-After-Impact (BAI) assessments. These scenarios are critical for transport applications, where tanks may be exposed to road collisions or foreign object strikes. In these cases, explicit FE simulations are used to evaluate how impact damage affects residual burst strength. This is a challenging task due to the localized, non-linear failure behavior of composites — but with accurate material models and a robust simulation methodology, it is feasible to predict impact damage zones and quantify safety margins post-impact.
The ability to simulate BAI and crash scenarios virtually enables OEMs to meet safety standards without exhaustive physical testing. For example, instead of manufacturing and bursting several tanks after impact or drop testing, a validated simulation can replace many of these iterations, saving time, material, and cost. Combined with multiscale laminate modeling and realistic compaction analysis, this expands the role of simulation from simple stress verification to a comprehensive safety assessment tool.
In summary, high-fidelity simulation — combining multiscale modeling, compaction analysis, process integration, and crash/impact prediction — dramatically reduces the number of required physical tests while increasing confidence in the design. For CIKONI’s clients, this means not only lower development costs, but also faster routes to certification and higher product safety.
Minimizing Carbon Fiber Usage through Better Design
Since carbon fiber is the single most expensive component of COPVs, reducing fiber usage has a direct impact on cost. The challenge is to do so without sacrificing strength or safety. This is where innovative design strategies come in – from tailoring fiber angles to adding targeted reinforcements only where needed. Two complementary approaches are: (1) optimizing the laminate architecture (redistributing fiber where it carries load best), and (2) introducing local reinforcements so that less material is needed overall.
Laminate architecture optimization might involve adjusting the mix of hoop vs. helical winding angles. For example, in some designs, a few high-angle helical layers near the dome can be replaced by more efficient reinforcement, allowing the removal of those layers. The provided whitepaper data indicates that removing high-angle helical layers yields more savings for longer vessels (higher length/diameter ratios) – i.e. a larger cylindrical proportion makes dome optimization even more beneficial. Thus, each vessel geometry has its own optimum, but in all cases the goal is to eliminate redundant fiber. Using simulation, one can iteratively remove or thin out low-effective layers and check that the design still meets burst requirements, thereby converging on a lean laminate.
Local Dome Reinforcement with Fiber Patch Placement (FPP) and other Approaches
One breakthrough method to cut fiber usage is local dome reinforcement (LDR). The dome ends of a pressure vessel experience complex stress states and traditionally are overwrapped with multiple layers of helical windings to ensure strength. LDR proposes applying extra composite material only on the domes in the form of patches, instead of globally overwrapping the whole cylinder with additional layers. In practice, this can mean a robot-driven system places tailor-made carbon fiber patches onto the liner’s dome (often using a resin-preimpregnated tape) in an automated sequence. These patches locally reinforce the dome’s stress hotspots. After patch placement, the standard filament winding of the vessel proceeds, tying everything together. CIKONI has developed several local reinforcement strategies and technologies with its clients based on both patch placement and preform technology.
The beauty of this approach is that it adds material where needed and removes material where it isn’t. By locally reinforcing the dome, one can reduce the thickness (or number of layers) of the conventional helical winding over the rest of the vessel. The net result is a significant material saving. In a recent award-winning project, this technique reduced the carbon fiber usage by about 15% while maintaining equivalent mechanical properties, by replacing some conventional layers with patch reinforcements. In fact, because the tank walls became thinner without loss of strength, the usable hydrogen storage capacity in the same volume increased by 17% (less wall = more internal volume). These are remarkable gains in both cost and performance.
It’s important to note that the LDR dome reinforcement concept has been known in theory for some time, but only recently has it become practical on an industrial scale. The key was integrating the LDR process with existing filament winding machines. In the project above, Cevotec developed a fully automated FPP system that can work in-line with standard winding equipment. The patches are placed on the liner, then the normal wet winding or towpreg winding continues right after. This integration means manufacturers don’t need an entirely separate production line – the FPP unit complements the filament winder, which is a cost-efficient way to adopt the technology. CIKONI’s role in that project was to ensure the design was optimized to take maximum advantage of the FPP reinforcement, and that the simulation predicted the burst pressure with the hybrid laminate. The success validated the approach.
Overall, minimizing fiber usage by improved design comes down to putting material exactly where it contributes to strength, and nowhere else. Techniques like LDR for domes, combined with computer-optimized winding patterns, enable this level of precision. As a side benefit, using less carbon fibers not only saves cost but also reduces the CO₂ footprint of production – for instance, saving ~9 tons of fiber per 10,000 tanks equates to avoiding ~234 tons of CO₂ emissions. Given industry concerns about increased sustainability regulations in the coming years, such material efficiency is increasingly crucial.
Early Integration of Automation and Manufacturing Strategies
A cost-optimized design is only as good as its manufacturability. If a theoretically optimal COPV laminate is hard to produce or slows down the production line, it could increase costs elsewhere. Design for Manufacturing (DfM) is therefore a critical aspect of cost reduction. This means considering automation, winding process constraints, and cycle times at the early design stage, and potentially adapting the design to fit efficient production methods.
One practical step is performing winding simulations and production feasibility studies in parallel with structural design and coupling them to cost predictions. For example, CIKONI’s development workflow for hydrogen tanks includes execution of filament winding simulations to evaluate producibility, machine control and feed cost models. By simulating the winding pattern on the dome and cylinder, engineers can detect if a proposed fiber path is feasible or if it would cause issues like fiber slippage or gaps. It also helps in estimating the winding time and identifying any need for special process routines. If a design is found to be difficult to wind, it can be re-optimized before any physical manufacturing – avoiding costly late design changes.
Automation considerations should also inform the design. Modern COPV production is highly automated (robotic winding machines, liner handling, automated logistics etc.), but introducing new features like patch reinforcements or non-traditional wind patterns means ensuring the automation can handle it. In the dome patch example, the team had to ensure the robot could place patches without collisions and that the winder could then overwrap them smoothly. By involving CIKONI’s automation engineers early, the design was engineered for seamless integration into large-scale production. This foresight addressed key cost drivers like material handling and processing time at the outset.
Another aspect is choosing the right machines, processes and materials for faster throughput. For instance, using towpreg (pre-impregnated fiber tow) instead of wet winding can speed up winding because it eliminates the resin bath variability. While towpreg material might be slightly more costly per kg, the time saved in production (and more consistent quality) can offset that. An optimal solution might involve hybridizing processes: wet winding for some layers and towpreg for others, or automated fiber placement for certain sections – whatever yields the best balance of material cost vs. labor and time.
Early integration of these manufacturing strategies ensures that when the design is finalized, it can be produced efficiently and with minimal hiccups. This reduces the risk of expensive redesigns or slow ramp-up during the industrialization phase. Engineering service providers like CIKONI emphasize this holistic approach: not just delivering a light design, but one that is production-ready. In practice, that means their project teams include experts in design, process automation, quality control, cost engineering and even machinery. They can, for example, custom-develop winding equipment or automation equipment to a given design. We will touch more on that comprehensive capability in a later section.
Process Innovations: Resin Uptake and Content Control
Material waste in composites can also occur through the resin system. In filament winding, especially wet winding, excess resin uptake can add unnecessary weight (and cost) without strengthening the structure — resin beyond what’s needed for fiber bonding simply increases vessel mass and can prolong curing times. Conversely, insufficient resin uptake can lead to dry spots, poor fiber wet-out, and internal voids, all of which degrade the mechanical performance and reliability of the laminate. Controlling resin content is thus a critical cost and quality factor. The goal is to achieve the target fiber volume fraction (typically around 60%) consistently throughout the vessel, ensuring optimal structural integrity with minimal waste.
There are a few strategies to control resin uptake:
- Resin bath calibration: In wet winding, the fibers pass through a resin bath. By adjusting resin viscosity, bath temperature, the resin gap, and pulling speed, manufacturers can control how much resin the fibers carry out. CIKONI’s self developed advanced systems use advanced design to eliminate excess resin, ensuring just the right amount remains on the fiber. This reduces resin waste (which is a direct cost) and prevents the composite from being heavier than needed.
- Fiber tension and winding speed: Higher fiber tension during winding compresses fibers together, which can squeeze out excess resin and result in a more compact laminate (higher fiber fraction). Conversely, if tension is too low, fibers may carry extra resin into the laminate. Proper control of tension and speed can thus influence resin content indirectly, optimizing the laminate quality.
- Pre-impregnated towpreg: As mentioned, using towpreg fiber (pre-impregnated with resin at a controlled fraction) virtually guarantees a consistent resin-to-fiber ratio. Towpreg winding has no open resin bath – the fiber comes with the resin content needed. This not only saves resin but also improves quality consistency at potentially higher winding speeds. The trade-off is the material cost of towpreg, but for high-volume production the cost is coming down, and the productivity gain can be worth it.
Maintaining the correct resin content improves consistency, reduces material waste, and shortens cure cycle times due to less resin mass to process. While advanced simulation models can account for localized fiber volume variations caused by inconsistent resin uptake, the preferred approach is to prevent these deviations at the source.
To address this, CIKONI offers a patent-pending in-process quality control system that continuously measures resin content during wet winding. This sensor-based system enables real-time detection of resin uptake fluctuations and dynamically adjusts resin bath parameters — such as doctor blade positioning, tensioning, and fiber pull speed — to maintain optimal impregnation. The result is a stable and well-impregnated laminate, with fiber volume fraction controlled to the design target across the entire structure. By closing the loop between process monitoring and control, CIKONI’s system ensures predictable laminate quality, avoids over- or under-impregnation, and helps manufacturers meet both performance and cost targets more reliably. This level of precision has become crucial in high-value industries such as aerospace, defense, and energy – and is increasingly indispensable for all safety-critical filament-wound systems beyond COPVs.
In-Process Fiber Alignment and Quality Monitoring (CWPWatch)
Even with the best design and process controls, quality variation can occur during manufacturing – a misaligned fiber, a wrinkle, or a gap can weaken a pressure vessel and lead to rework or scrap (which is wasted cost). That’s why in-process quality monitoring is crucial, especially for automated processes like filament winding. CIKONI addresses this with a technology suite originally called DrapeWatch, adapted for filament winding as CWPWatch (Composite Winding Process Watch). This system uses sensors and optical inspection to watch the fiber placement in real time during production.
CWPWatch monitors the fiber winding on the fly, checking for deviations in fiber angle, bandwidth, or gaps between roving passes. If an error is detected (e.g., a misaligned band or an overlap), the system can alert operators or even automatically adjust the process if possible. By catching issues during winding, CWPWatch prevents defective layers from being buried under subsequent layers. This can reduce scrap and rework significantly, as defects can be corrected on the spot rather than discovered in final inspection when the only option might be to scrap the vessel.
The benefits of such real-time monitoring are multiple. First, it ensures each tank meets the design intent, which maintains safety (critical for H₂ service) and avoids hidden flaws. Second, it provides a cost reduction by minimizing defects and rejects – fewer scrapped tanks means lower overall cost per good part. Third, it actually helps in process optimization: CWPWatch can feed data back into the design and simulation loop. For example, the recorded fiber orientations from production can be fed directly back into simulation, creating a closed loop between manufacturing and design. This means the simulation models can be updated with “as-built” fiber paths, improving their accuracy for future design iterations. Over time, this learning loop makes both the product and process more robust.
Quality monitoring systems like CWPWatch are part of a broader trend of Industry 4.0 in composites manufacturing – using sensors, vision systems, and data analysis to achieve zero-defect production. For COPV manufacturers, investing in such technology pays off by ensuring consistent product performance (essential for certifications) and by driving down the cost of non-quality. By catching a fiber placement error that might have caused a composite pressure vessel to fail burst testing, the system saves not just that tank but also the downtime and investigation that would follow a test failure.
In summary, real-time fiber alignment monitoring is a powerful tool to safeguard quality and cost in COPV manufacturing. CIKONI’s CWPWatch and ResinUptake systems exemplify this approach for filament winding, helping produce safe and lightweight pressure tanks with confidence.
CIKONI’s Holistic Composites Engineering Solution
As we’ve discussed, cost reduction in composite pressure vessels comes from a multidisciplinary optimization – spanning design, simulation, materials, process, and automation. CIKONI positions itself as a one-stop solution provider in composites engineering, able to support projects at each stage. By having expertise under one roof, the iterative loops between design and manufacturing can be closed quickly and efficiently.
From concept to detailed design: CIKONI assists with concept development and feasibility studies for high-pressure composite tanks. Early on, we consider different material options (carbon fiber, hybrid composites, liner materials) and geometry choices. Once a concept is chosen, our team carries out laminate design and optimization using advanced simulation techniques as described earlier.
Advanced simulation and testing: With specialists in FEA of composites, CIKONI builds simulation models to ensure load capacity in all scenarios, optimizes the vessel geometry and layer structure, and even predicts power-to-weight ratio and achievable material savings. We also coordinate physical testing programs for material characterization up to full system tests, ensuring the simulations are grounded in reality. Our multiscale simulation capability enables predicting failure (burst) accurately and reducing physical testing needs.
Manufacturing process development: Unlike purely design consultancies, CIKONI also delves into manufacturing engineering. We perform winding process development – whether wet, towpreg, or even thermoplastic winding – choosing what best fits the project. Winding simulations are used to link the manufacturing parameters with the structural performance. We pay attention to practical details like tool design and cycle time optimization. If needed, CIKONI can contribute to or design automation hardware: for instance, custom developments on filament winding machines, or integration of in-line measurement systems like CWPWatch into a production line. In the dome reinforcement project, CIKONI’s collaboration with machinery partners (like Roth Composite Machinery) is a testament to their automation integration expertise.
Prototyping and validation: CIKONI supports building prototype pressure vessels and planning the test campaigns (burst tests, permeation tests, fatigue, drop tests etc.). Our involvement ensures that any discrepancies between test and simulation are quickly analyzed and fed back into the design loop. Because we understand both the simulation and the manufacturing sides, we can pinpoint whether an issue is due to a design aspect or a manufacturing variation, and then resolve it efficiently.
Quality systems and optimization: Lastly, through solutions like DrapeWatch/CWPWatch, CIKONI provides the tools for in-line quality assurance in production that tie back into design. This closes the development loop – the as-built data improves the next design, and the design is made tolerant to manufacturing realities.
By offering this end-to-end service, CIKONI helps manufacturers of hydrogen and CNG pressure vessels achieve cost reduction targets faster. An integrated approach can streamline the whole project. The result is an optimized product and process that are ready for commercialization.
Conclusion
In the drive to make hydrogen and CNG storage more affordable and scalable, applying these cost-reduction strategies for composite pressure vessels is essential. Simulation-driven optimization, high-fidelity virtual testing, lean laminate design, early automation integration, careful resin control, and rigorous in-process quality monitoring together form a toolkit that can substantially lower material and development costs while enhancing performance. The examples discussed – from a 15% fiber savings via dome patches to faster development cycles using multiscale simulation – show that with the right expertise, cutting costs does not mean cutting corners on safety or efficiency.
For organizations looking to implement these advanced strategies, partnering with a knowledgeable engineering partner can make all the difference. CIKONI offers a comprehensive package in this domain, acting as a consultant and development partner from the initial idea through to manufacturing readiness. Our experience in composites, carbon fiber design, COPV simulation, automation equipment, and quality systems enables us to tailor solutions to each project’s needs.
If you are seeking to optimize composite pressure vessels – whether for fuel cell vehicles, gas transport, or any high-pressure application – and want to explore how these cost-saving approaches can apply to your products, we encourage you to reach out to us. With our end-to-end expertise, we can help turn ambitious targets into realized savings and performance gains. Contact CIKONI for a consultation on your composite pressure vessel project and take the next step toward a lighter, more cost-effective, and reliable product line.
(CIKONI GmbH, based in Stuttgart, Germany, specializes in composites engineering and automation. We can be contacted at +49 711 263756-00 or via email at info@cikoni.com for inquiries.)
