Skip to main content
SpringerLink
Log in

Experimental Strain Measurement for Fibre-Reinforced Finite Mulitlayered Composites with Cut-out Under Bending for Validating an Analytical Calculation Model

  • Published:
Experimental Techniques Aims and scope Submit manuscript

Abstract

For validating a newly developed analytical calculation method for the layer-by-layer stress-strain analysis of thin-walled notched multilayered composites with finite outer boundary, the strain field of specimen with cut-out is experimentally determined. For this reason, a unique flexural testing device is enhanced and adapted for composites undergoing large deflection. The strains and their gradients around the cut-out are measured using a digital image correlation technique. Beyond that, especially for the investigation of small measuring fields with a high local resolution and/or with a large relocation during the experiment, a new tracking method for the measurement system is developed and applied. In the case of specimen deflection caused by bending, that system keeps the relative distance and position between the measuring field on the specimen and the optical measuring system within the allowable range. By using the combination of enhanced flexural testing device and new tracking system, the 2D strain-field on the specimen surface is measured with a high local accuracy and shows a good correlation with the predicted strain-field calculated with the new analytical calculation method.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11

Similar content being viewed by others

Notes

  1. Whilst the deformation gradients remain still small.

  2. Influences induced by the belt strap or the bearings are neglected.

  3. However, depending on the application it also may be feasible to neglect the applied load, but to regard the appearing absolute deflection as reference if comparing the resulting strain values from calculation and experiment.

  4. Geometry and material properties required for the investigations of the problem given here of thin-walled laminates are displayed in Table 1; since the CLT is applied, the needed in-plane properties are given.

  5. The influence of the specimen dead weight itself is supposed to be negligible for the investigations.

  6. On the one hand due the longitudinal movement the measurement field would move outside the view of the camera during the bending test and on the other hand the limit of the depth of field of the camera system would be exceeded due to the lateral movement.

References

  1. Hufenbach W, Grüber B, Gottwald R, Lepper M, Zhou B (2010) Analytical and experimental stress concentration analysis of notched multilayered composites with finite outer boundaries. Mech Compos Mater. https://doi.org/10.1007/s11029-010-9169-3

  2. Grüber B (2004) Beitrag zur Strukturanalyse von anisotropen Schichtverbunden mit elastischen Einschlüssen und Bolzen (Contribution to the structural analysis of anisotropic multilayer composites with elastic inclusions and bolts). PhD thesis, TU Dresden

  3. Hufenbach W, Grüber B, Lepper M, Gottwald R, Zhou B (2013) An analytical method for the determination of stress and strain concentrations in textile-reinforced GF/PP composites with elliptical cutout and a finite outer boundary and its numerical verification Arch Appl Mech. https://doi.org/10.1007/s00419-012-0641-5

  4. Lekhnitskii SG (1968) Anisotropic Plates. Transl. 2nd russ. print run: S. W. Tsai and T. Cheron.; Gordon and Breach New York others

  5. Becker W (1993) Complex method for the elliptical hole in an unsymmetric laminate. Arch Appl Mech. https://doi.org/10.1007/BF00794890

  6. Altenbach H, Altenbach J, Rikards R (1996) Einführung in die Mechanik der Laminat- und Sandwichtragwerke: Modellierung und Berechnung von Balken und Platten aus Verbundwerkstoffen (Introduction to the mechanics of laminates and sandwiches: modelling and analysis of composite beams and plates). Deutscher Verlag für Grundstoffindustrie Stuttgart

  7. Kaw AK (2006) Mechanics of composite materials, 2nd edn. CRC Press Taylor & Francis Group, New York

    Google Scholar 

  8. Kolosov GV (1914) Über einige Eigenschaften des ebenen Problems der Elastizitätstheorie (On some properties of the plane problem in the theory of elasticity). Zeitschrift für Mathematik und Physik 26:384–409

    Google Scholar 

  9. Kolosov GV (1935) Application of function of complex variable to the elasticity theory. ONTI, Moscow. (In Russian)

  10. Musschelischwili NJ (1935) Nekotorye osnovnye zadachi matematicheskoi teorii uprugosti (Some Basic Problems of the Mathematical Theory of Elasticity). Moskva. (In Russian)

  11. Sawin GN (1956) Spannungserhöhung am Rande von Löchern (Translation and scientific editing.: H. Neuber). VEB Verlag Technik, Berlin

    Google Scholar 

  12. Grüber B, Hufenbach W, Gottwald R, Lepper M, Modler N, Zhou B (2014) Novel testing device for the experimental stress concentration analysis of multilayer textile composites under in-plane compressive load. Key Engineering Materials. https://doi.org/10.4028/www.scientific.net/KEM.601.7

  13. Grüber B, Hufenbach W, Gottwald R, Lepper M, Zhou B Experimental and numerical validation of an analytical calculation method for notched fibre-reinforced multilayered composites under bending and compressive loads. In: Van Hoa S, Hubert P (eds) Proceedings of the 19th international conference on composite materials : ICCM-19, Montreal, Canada, 28 July - 2 August 2013, pp 4543–4552

  14. Gottwald R (2015) Beitrag zur analytischen, numerischen und experimentellen Kerbspannungsanalyse endlich berandeter anisotroper Mehrschichtverbunde (Contribution to analytical, numerical and experimental stress concentration analysis of anisotropic multilayered composites with a finite boundary). PhD thesis, TU Dresden

  15. Faserverstärkte Kunststoffe - (2011) Bestimmung der Biegeeigenschaften (Fibre-reinforced polymers - Determination of the flexural properties). DIN EN ISO, vol 14125. Deutsches Institut für Normung, Berlin

    Google Scholar 

  16. Eberle K, Häberle J (1989) Verfahren und Prüfmaschine zur Festigkeitsuntersuchung von Werkstoffen oder Bauteilen (Method and testing machine for testing the strength of materials or components). Patentanmeldung DE 38 15 423 A1 Offenlegungstag: 16.11

  17. Lippmann H, Mannl V, Reigl M (2002) Vorrichtung zum freien plastischen Biegen eines Werkstückes (Device for free plastic bending of a workpiece). Patentschrift DE 43 10 773 C2 Patenterteilung: 17.10

  18. Modler K-H, et al. (2008) Kinematikprüfstand zur statischen und dynamischen Prüfung von Faserverbundplatten bei querkraftfreier Biegung (Kinematic test device for the static and dynamic investigation of fibre composite plates at flexure free of lateral forces). In: VDI-Berichte: Nr. 2050. VDI-Verlag, Düsseldorf, pp 195–210

  19. Jaschinski J (2012) Zum Strukturverhalten dünnwandiger Leichtbau-Sandwichbleche (On the structural behaviour of thin-walled lightweight sandwich sheets). PhD thesis, TU Dresden

  20. http://www.ast.de/files/pdf/mess-und-regeltechnik/sensoren/D_KMT_KAP-S.pdf Accessed 6 Dec 2017

  21. Schmidt T, Tyson J, Galanulis K (2003) Full-field dynamic displacement and strain measurement using advanced 3D image correlation photogrammetry: Part 1. Experimental Techniques. https://doi.org/10.1111/j.1747-1567.2003.tb00115.x

Download references

Acknowledgements

The authors would like to express their gratitude towards the Deutsche Forschungsgemeinschaft (DFG), who funded this research in the subproject B2 within the scope of the Collaborative Research Centre SFB 639 “Textile-Reinforced Composite Components in Function-Integrating Multi-Material Design for Complex Lightweight Applications”.

Author information

Authors and Affiliations

  1. Institute of Lightweight Engineering and Polymer Technology (ILK), Technische Universität Dresden, Holbeinstr. 3, 01307, Dresden, Germany

    B. Grüber, R. Gottwald, M. Gude, M. Lepper, N. Modler & B. Zhou

Authors
  1. B. Grüber
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. R. Gottwald
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. M. Gude
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. M. Lepper
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. N. Modler
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. B. Zhou
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to B. Grüber.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Grüber, B., Gottwald, R., Gude, M. et al. Experimental Strain Measurement for Fibre-Reinforced Finite Mulitlayered Composites with Cut-out Under Bending for Validating an Analytical Calculation Model. Exp Tech 43, 149–159 (2019). https://doi.org/10.1007/s40799-018-0275-9

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s40799-018-0275-9

Keywords

Search

Navigation