Modelling hollow pultruded FRP profiles under axial compression: Local buckling and progressive failure

Alhawamdeh, Mohammad; Alajarmeh, Omar; Aravinthan, Thiru; Shelley, Tristan; Schubel, Peter; Kemp, M.; Zeng, Xuesen

doi:10.1016/j.compstruct.2021.113650

Cited by 33 publications

(23 citation statements)

References 59 publications

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“…To eliminate the dependency of the incremental solution on the number of increments when buckling is dominant, the maximum increment size was reduced down to 0.35% of the total step time until convergence was achieved with a tolerance of 5% between the load capacities of the successive increment sizes. This novel modelling approach combining the local buckling, post-buckling, and progressive failure behaviours was addressed in detail and verified in previous research under compression [16]. However, when studying the convergence at the current problem under bending, the solution was noticed to converge faster against the number of increments compared to compression, as shown in Fig.…”

Section: Local Buckling and Progressive Failure Behaviourssupporting

confidence: 63%

“…A reliable modelling approach was established in order to obtain accurate predictions. An adjustment was performed on the incremental approach presented by the authors [16] to suit flexural loading and reduce the computational cost. A large experimental program comprising 20 beams was performed to validate this modelling approach under four-point bending.…”

Section: Discussionmentioning

confidence: 99%

“…Thus, the buckle half-wavelength under axial compression is smaller compared to the response under bending. Smaller buckle halfwavelength means that more buckling waves will appear due to the lower restraint provided by the other walls, since they are also buckled, in compression loading [14][15][16]. Consequently, local buckling of walls is more critical under axial compression compared to bending.…”

Section: Introductionmentioning

confidence: 99%

“…After studying the failure mechanism of hollow box PFRP profiles under axial compression [16], this paper is going to investigate the failure mechanism of these profiles under bending experimentally and numerically. The incremental modelling approach presented by the authors [16] for compression was further developed with fast convergence under flexural loading while improving the computational efficiency. The validated model is going to be used to study the effect, contribution, and interaction of the design parameters under four-point bending by full factorial design of experiment.…”

Section: Introductionmentioning

confidence: 99%

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Modelling flexural performance of hollow pultruded FRP profiles

Alhawamdeh

Alajarmeh

Aravinthan

et al. 2021

Composite Structures

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Hollow Pultruded Fibre-Reinforced Polymer (PFRP) profiles, as novel construction material, require further development of design tool to broaden the applications. This paper proposes a combined experimental and numerical methodology as a design tool to investigate the failure modes of these profiles under four-point bending. Two different profiles, each with 10 samples, were tested until failure and were used to validate the numerical model. A finite element model was built based on a fast-convergence incremental approach that suits flexural loading and reduces the computational cost. The validated model was used to study the failure sequence thoroughly and perform an extensive parametric study on the design parameters. Each geometric parameter was studied individually first to determine the relevant levels for each parameter in the full factorial study. A full factorial design of experiment was used to capture the critical parametric interactions with over 81 numerical models. The design rules and recommendation were established for the optimal flexural behaviour of hollow box PFRP profiles to withstand local buckling of the top flange.

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Section: Local Buckling and Progressive Failure Behaviourssupporting

confidence: 63%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Modelling flexural performance of hollow pultruded FRP profiles

Alhawamdeh

Alajarmeh

Aravinthan

et al. 2021

Composite Structures

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“…Pultrusion is the most efficient process for producing composite structural profiles of constant cross-sections [ 1 , 2 , 3 ]. Owing to their high strength-to-weight ratio [ 4 , 5 ], superior corrosion resistance [ 6 , 7 ], and improved durability [ 8 , 9 ], pultruded profiles have been successfully used as structural elements in the fields of bridge construction [ 10 , 11 , 12 ], civil [ 13 , 14 ], and architectural engineering [ 15 , 16 ]; marine construction [ 17 , 18 ]; aerospace and aviation engineering [ 19 , 20 , 21 ]; transportation [ 22 , 23 ]; and energy systems [ 24 ]. However, process-induced deformations, such as spring-in (common in curved elements) and warpage (common in flat elements), may result in a certain loss in the economic efficiency of mass production of composite profiles [ 25 ].…”

Section: Introductionmentioning

confidence: 99%

Modeling Spring-In of L-Shaped Structural Profiles Pultruded at Different Pulling Speeds

et al. 2021

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Cure-induced deformations are inevitable in pultruded composite profiles due to the peculiarities of the pultrusion process and usually require the use of costly shimming operations at the assembly stage for their compensation. Residual stresses formed at the production and assembly stages impair the mechanical performance of pultruded elements. A numerical technique that would allow the prediction and reduction of cure-induced deformations is essential for the optimization of the pultrusion process. This study is aimed at the development of a numerical model that is able to predict spring-in in pultruded L-shaped profiles. The model was developed in the ABAQUS software suite with user subroutines UMAT, FILM, USDFLD, HETVAL, and UEXPAN. The authors used the 2D approach to describe the thermochemical and mechanical behavior via the modified Cure Hardening Instantaneous Linear Elastic (CHILE) model. The developed model was validated in two experiments conducted with a 6-month interval using glass fiber/vinyl ester resin L-shaped profiles manufactured at pulling speeds of 200, 400, and 600 mm/min. Spring-in predictions obtained with the proposed numerical model fall within the experimental data range. The validated model has allowed authors to establish that the increase in spring-in values observed at higher pulling speeds can be attributed to a higher fraction of uncured material in the composite exiting the die block and the subsequent increase in chemical shrinkage that occurs under unconstrained conditions. This study is the first one to isolate and evaluate the contributions of thermal and chemical shrinkage into spring-in evolution in pultruded profiles. Based on this model, the authors demonstrate the possibility of achieving the same level of spring-in at increased pulling speeds from 200 to 900 mm/min, either by using a post-die cooling tool or by reducing the chemical shrinkage of the resin. The study provides insight into the factors significantly affecting the spring-in, and it analyzes the methods of spring-in reduction that can be used by scholars to minimize the spring-in in the pultrusion process.

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A new parameter to describe crippling strength: Experimental and theoretical investigations for post‐buckling behaviors of the composite structures

Yıldırım,

Ünal

2023

Polymer Composites

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The post‐buckling strength, which is simply called as crippling, is investigated for laminated composite structures in this study. L profiles that had various stacking sequences of carbon fiber reinforced epoxies were tested. Three different layups configurations were used by changing flange‐to‐thickness ratios. The main objective of this research was to show that flange‐to‐thickness ratio was not the only effecting parameter for crippling. Therefore, a new parameter, EGY number, was developed by considering the positions of 0° and 45° plies. Depending on EGY number, a new semi‐empirical formulation was presented to calculate crippling strength of the laminated composite structures. One of the test results was employed to verification of EGY number. In addition, the test results were validated with finite element analyses. Static, Riks and Dynamic, Explicit computational results were compared to simulate the experiments.Highlights Determination of crippling strength both experimentally and theoretically. Comparison of numerical models: Static, Riks versus Dynamic, Explicit. Developing a new parameter called as EGY number. Developing of a new analytical semi‐empirical formula for crippling strength.

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Modelling hollow pultruded FRP profiles under axial compression: Local buckling and progressive failure

Cited by 33 publications

References 59 publications

Modelling flexural performance of hollow pultruded FRP profiles

Modelling flexural performance of hollow pultruded FRP profiles

Modeling Spring-In of L-Shaped Structural Profiles Pultruded at Different Pulling Speeds

A new parameter to describe crippling strength: Experimental and theoretical investigations for post‐buckling behaviors of the composite structures

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