How the Test Setup Can Affect Single Fiber Tensile Testing

ABSTRACT

Tensile testing is the most common method to investigate natural fibers. The fibers’ mechanical behavior can be considered non-linear and is influenced by viscoelasticity, plasticity, and environmental conditions. Very often such fibers are tested by gluing them with an adhesive onto a sample holder. Such a system consisting of a polymeric sample holder, adhesive, and natural fiber is complex and there is a risk that the mechanical response measured is a mix of the different contributions of those components. In this work, the key components for tensile testing of natural fibers ‒ sample holder and adhesive ‒ are investigated, to determine their influence on the measurement results. In order to isolate the influence of the measurement setup, the natural fiber is replaced with a platinum wire, which is purely linear-elastic. Hence all non-linear contributions from sample holder or adhesive can be identified. The main influence factor on the results was the glue used for fixating the fiber on the sample holder. Epoxy resin was found to be best suited. Taking these findings into account, a series of tensile tests was performed on cellulose-based natural fibers for demonstration but is applicable to any natural fiber.

摘要

拉伸试验是研究天然纤维最常见的方法. 纤维的力学行为可以被认为是非线性的，并受到粘弹性、塑性和环境条件的影响. 这种纤维通常通过用粘合剂将它们粘合到样品支架上来进行测试. 这种由聚合物样品支架、粘合剂和天然纤维组成的系统是复杂的，并且存在测量的机械响应是这些成分的不同贡献的混合的风险. 在这项工作中，研究了天然纤维拉伸测试的关键部件——样品支架和粘合剂，以确定它们对测量结果的影响. 为了隔离测量设置的影响，天然纤维被纯线性弹性的铂丝取代. 因此，可以识别来自样品支架或粘合剂的所有非线性. 影响结果的主要因素是用于将纤维固定在样品支架上的胶水. 发现环氧树脂最适合. 考虑到这些发现，对纤维素基天然纤维进行了一系列拉伸试验以进行证明，但适用于任何天然纤维.

KEYWORDS:

• Cellulosic fibers
• tensile testing
• validation
• mechanical properties

关键词:

• 纤维素纤维
• 拉伸试验
• 验证
• 机械性能

Acknowledgments

The financial support by the Austrian Federal Ministry for Digital and Economic Affairs and the National Foundation for Research Technology and Development is gratefully acknowledged. We also thank our industrial partners Mondi Group, Canon Production Printing, Kelheim Fibres GmbH, SIG Combibloc Group AG for fruitful discussions and their financial support. Special thanks to Angela Wolfbauer of the Institute of Bioproducts and Paper Technology, Graz University of Technology for sample preparation and Dr. August Brandberg for helpful suggestions.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author’s contribution

M.Z. and C.C. wrote the main manuscript. M.Z., C.C. and U.H. outlined the experimental work. M.Z. performed most of the experiments and analyzed the data. Single fiber testing demonstrations were performed and analyzed by C.C. U.H. provided funding and supervised the work. All authors reviewed the manuscript and contributed to the interpretation of the results.

Consent

The work presented in this manuscript does not raise any issues concerning consent.

Data availability statement

The data that support the findings of this study are available from the corresponding author, U. H., upon reasonable request.

Ethical approval

The work presented in this manuscript does not raise any ethical issues.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/15440478.2024.2328264

Additional information

Funding

M. Z. and U. H. thank the EU Horizon 2020 Program under Marie Sklodowska-Curie Grant Agreement 764713, ITN Project FibreNet. C. C. acknowledges the Hertha Firnberg program [project no. T 1314-N] of the Austrian Science Fund (FWF) for funding.