In this work, the stress distribution along cylindrical composite pressure vessels with different dome geometries is investigated. The dome contours are generated through an integral method based on shell stresses. Here, the influence of each dome contour on the stress distribution at the interface of the dome-cylinder is evaluated. At first, the integral formulation for dome curve generation is presented and solved for the different dome contours. An analytical approach for the calculation of the secondary stresses in a cylindrical pressure vessel is introduced. For the analysis, three different cases were investigated: (i) a polymer liner; (ii) a single layer of carbon-epoxy composite wrapped on a polymer liner; and (iii) multilayer carbon-epoxy pressure vessel. Accounting for nonlinear geometry is seen to have an effect on the stress distribution on the pressure vessel, also on the isotropic liner. Significant secondary stresses were observed at the dome-cylinder interface and they reach a maximum at a specific distance from the interface. A discussion on the trend in these stresses is presented. The numerical results are compared with the experimental results of the multilayer pressure vessel. It is observed that the secondary stresses present in the vicinity of the dome-cylinder interface has a significant effect on the failure mechanism, especially for thick walled cylindrical composite pressure vessel. It is critical that these secondary stresses are directly accounted for in the initial design phase.

In the field of textile technology, this study centers on towpreg—an integral component utilized in production techniques like tape laying and filament winding. Here, fibers are pre‐coated with resin, typically epoxy but not exclusively. Notably, towpreg retains a partially cured state, maintaining tackiness throughout the processing stages. The ultimate quality of the product manufactured with this towpreg is highly dependent on this initial material. This research highlights the importance of considering various factors that impact product quality. While not exhaustive, a systematic analysis of diverse towpreg parameters, including tack, resin content, and width, is provided. The work encompasses findings, challenges, and insights derived from towpreg manufacturing, incorporating the investigation of various experimental methodologies. The study also evaluates methodologies for laminated coupon production with towpreg, assessing their applicability in characterizing filament‐wound components. Although the article seems like a review, the authors aim to give a clear and holistic picture in one work instead of spreading information across many articles.Highlights: Techniques for the quantification of towpreg tack are presented. Resin content distribution along towpreg length is presented. Towpreg width variation was investigated, seen to be one of the major causes for the gaps and voids in a filament wound composite. Coupon‐level characterization of towpreg through filament winding approach is presented. Other filament winding parameters influencing the quality of the manufactured composite are discussed.

Woven composites are widely used across various applications, characterized by the warp and weft tows that intersect perpendicularly to form a weave pattern. Often, the weave architecture is neglected during analysis. This study explicitly models the weave pattern and the undulation of the tows using the NASA Multiscale Analysis Tool, incorporating statistical constituent material properties and measurements of unbalanced composite microstructures. Experimental data and multiscale modeling results were compared for carbon fiber composites manufactured with different tow sizes in the two in-plane directions, resulting in four distinct unbalanced reinforcement patterns. Multiple tensile tests were conducted for each pattern. Using statistical input data, 1000 random model instances were created for each unbalanced composite, predicting distributions of the composite’s Young’s modulus and tensile strength. The predictions demonstrated good agreement with test data, highlighting unique aspects of the modeling approach.