TY - JOUR AU - Szekrényes, András AU - Uj, József TI - Over-leg bending test for mixed-mode I/II interlaminar fracture in composite laminates JF - INTERNATIONAL JOURNAL OF DAMAGE MECHANICS J2 - INT J DAMAGE MECH VL - 16 PY - 2007 IS - 1 SP - 5 EP - 33 PG - 29 SN - 1056-7895 DO - 10.1177/1056789507060774 UR - https://m2.mtmt.hu/api/publication/2635071 ID - 2635071 N1 - Cited By :34 Export Date: 23 August 2022 CODEN: IDMEE Correspondence Address: Szekrényes, A.; Department of Applied Mechanics, PoB 11, Budapest H-1521, Hungary AB - In this work the over-leg bending (OLB) specimen is developed for mixed-mode I/II delamination characterization in composites. The traditional single-leg bending (SLB) specimen is modified by introducing the load eccentrically between the two supports of a three-point bending setup. The modified configuration is analyzed by using linear beam theories. The theories of transverse shear, Winkler-Pasternak- type elastic foundation, Saint-Venant effect, and crack tip shear deformation are incorporated in the analysis. Also, experiments are carried out on glass/polyester unidirectional specimens. Comparison between the results of analysis and experiment shows very good agreement. The traditional SLB and the novel OLB coupons are compared, and their advantages and drawbacks are highlighted. The newly developed OLB setup is relatively easier to perform and crack propagation may be simply investigated under displacement control. LA - English DB - MTMT ER - TY - JOUR AU - Szekrényes, András AU - Uj, József TI - Comparison of some improved solutions for mixed-mode composite delamination coupons JF - COMPOSITE STRUCTURES J2 - COMPOS STRUCT VL - 72 PY - 2006 IS - 3 SP - 321 EP - 329 PG - 9 SN - 0263-8223 DO - 10.1016/j.compstruct.2005.01.002 UR - https://m2.mtmt.hu/api/publication/2635067 ID - 2635067 N1 - Cited By :32 Export Date: 23 August 2022 CODEN: COMSE Correspondence Address: Szekrényes, A.; Department of Applied Mechanics, POB 11, H-1521 Budapest, Hungary; email: szeki@mm.bme.hu AB - Four different solutions for the energy release rate of orthotropic, beam-like fracture specimens were compared in the present work. Two beam theory-based approaches were utilized. The current authors developed one of them, the other one was previously published in the literature. A model based on refined plate theory was also considered. Finally equations based on a numerical calibration technique were utilized as a fourth solution. These solutions were extended for the case of composite double-cantilever beam, end-loaded split, single-leg bending and mixed-mode bending fracture specimens. Comparison between the different solutions shows somewhat distinct results, especially for the mode ratio. There are some explanations for the experienced discrepancies between the mentioned solutions. (c) 2005 Elsevier Ltd. All rights reserved. LA - English DB - MTMT ER - TY - THES AU - Szekrényes, András TI - Delamination of composite specimens PB - Budapesti Műszaki és Gazdaságtudományi Egyetem PY - 2005 SP - 117 UR - https://m2.mtmt.hu/api/publication/2564696 ID - 2564696 LA - English DB - MTMT ER - TY - JOUR AU - Szekrényes, András AU - Uj, József TI - Mode-II fracture in E-glass-polyester composite JF - JOURNAL OF COMPOSITE MATERIALS J2 - J COMPOS MATER VL - 39 PY - 2005 IS - 19 SP - 1747 EP - 1768 PG - 22 SN - 0021-9983 DO - 10.1177/0021998305051120 UR - https://m2.mtmt.hu/api/publication/2635066 ID - 2635066 AB - In this work a novel beam analysis of the end-loaded split (ELS) and over-notched flexure (ONF) specimens are presented. New compliance and strain energy release rate equations are developed incorporating crack tip deformation and transverse shear analysis. The Saint Venant effect at the clamped end of the ELS specimen is also considered. Unidirectional glass-polyester specimens are manufactured and experimental (initiation and propagation) tests are performed to confirm the theoretical models. The experimental data is evaluated by means of four reduction techniques: the exact beam theory, virtual crack closure technique, compliance calibration method, and direct beam theory. It is shown that the results by the four methods agree quite closely; however, the compliance calibration method is not recommended for initiation data reduction in the case of the ONF specimen. The ELS specimens suffer from relatively large displacements. Thus, propagation tests are not possible to be performed. The ONF test seems to be a better tool to evaluate the mode-II toughness of composite materials with low flexural modulus. LA - English DB - MTMT ER - TY - JOUR AU - Szekrényes, András AU - Uj, József TI - Beam and finite element analysis of quasi-unidirectional composite SLB and ELS specimens JF - COMPOSITES SCIENCE AND TECHNOLOGY J2 - COMPOS SCI TECHNOL VL - 64 PY - 2004 IS - 15 SP - 2393 EP - 2406 PG - 14 SN - 0266-3538 DO - 10.1016/j.compscitech.2004.05.002 UR - https://m2.mtmt.hu/api/publication/2635064 ID - 2635064 AB - The mixed-mode I/II delamination problem in composite specimens was investigated using closed-from solutions, the finite element technique and experiments. Unidirectional glass/polyester composite laminates were manufactured and tested. The mixed-mode I/II SLB and ELS specimen configurations were used in order to obtain compliance and fracture energy predictions. Linear beam theories incorporating transverse shear and elastic foundation effects were utilized to calculate the displacements of both the SLB and ELS specimens. The compliance and fracture energy was calculated as the superposition of the various contributions. Plane stress finite element models including some accompanying effects were constructed. The analytical and numerical results were compared with the experiments and very good agreement was found. (C) 2004 Elsevier Ltd. All rights reserved. LA - English DB - MTMT ER -