Fatigue behaviour of additively manufactured polylactide (PLA)

Ezeh, O.H.; Susmel, Luca

doi:10.1016/j.prostr.2018.12.121

Cited by 16 publications

(13 citation statements)

References 7 publications

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“…The spread between results is relatively small. Tests done by [11] show an order of magnitude difference between the top and bottom 10% of samples. Results of the experiments performed in this paper all show a difference of the highest and lowest results of less than an order of magnitude.…”

Section: Fatigue Testingmentioning

confidence: 99%

“…Elastic behavior for thin-walled structures can, therefore, be approximated as isotropic [5,33,40]. Experimental work done by Afrose et al, [1,11,12,26] have indicated that the slope of the s-n diagram of the material is not dependent on the orientation of the printing direction. The structure designed has a primary filament orientation aligned with the applied forces.…”

Section: Improving the Cycles Until Initial Failurementioning

confidence: 99%

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Improving the fatigue life of printed structures using stochastic variations

et al. 2022

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Additive manufacturing allows designers to create geometries that would not be possible or economical to manufacture using traditional manufacturing processes. Production with these technologies does, however, introduce a large amount of variation and additional unknowns. These random variations from idealized geometry or material properties can harm the performance of the design. The current work presents an approach to improve the fatigue life of such structures, and simultaneously reduce its influence from random variations in local thickness. Following an initial numerical study, the results are experimentally validated. Experimental results show a significant improvement in fatigue life in the redesigned sample with a tailored thickness distribution.

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Section: Fatigue Testingmentioning

confidence: 99%

Section: Improving the Cycles Until Initial Failurementioning

confidence: 99%

Improving the fatigue life of printed structures using stochastic variations

et al. 2022

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“…Firstly, because it is one of the most common thermoplastics used in FFF printing (Popescu et al, 2018) (the other most common one being acrylonitrile butadiene styrene [ABS]). Secondly, PLA is easy to print (Ezeh and Susmel, 2018). Finally, it has higher rigidity, tensile strength and layer adhesion compared to ABS (Rodríguez-Panes et al, 2018).…”

Section: Materials Selectionmentioning

confidence: 99%

Guidelines for 3D printed springs using material extrusion

Enea

Moon

2021

RPJ

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Purpose Springs are an integral part of mechanisms and can benefit from additive manufacturing’s (AM) increased design freedom. Given the limited literature on the subject, the purpose of this paper is to develop guidelines for fabricating helical springs using three-dimensional (3D) printing. Design/methodology/approach Polylactic acid (PLA) is the main material investigated, with ULTEM™ 9085 used as a comparison. The experimental procedure is to vary the spring parameters, print the springs and test them in tension or compression using constant velocity. Plots of the force and displacement are used to measure the linear and post-deformation spring constants. Loading of the springs is done both to breakage and cyclically. Cyclic loading is also used to observe the plastic behaviour of the springs. Parameters that are varied include wire and coil diameters, pitch, wire cross-section, in-fill and layer height. Findings A square wire cross-section is used, instead of a circle because it produces more consistent coils. In-fills make no significant difference in the elastic stiffness of the springs but the mono in-fill breaks at a greater extension, so it is recommended. Tension and compression springs are confirmed to behave the same when in the elastic regime. ULTEM™ 9085 produces consistently weaker springs compared to PLA. Variation of layer height shows that thinner layers increase the stiffness of the springs. Originality/value This study investigates the behaviour of 3D printed helical springs in tension and compression. Three guidelines are created: square wire cross-section, mono-directional in-fill and thin layers are recommended.

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“…In this context, the available technical literature makes it evident that in recent years the international scientific community has focussed its attention mainly on the mechanical behaviour and strength of AM PLA when this polymer is subjected to static loading (see Refs [3][4][5][6][7][8][9][10] and the references reported therein). In contrast, just a few studies dealing with the fatigue behaviour of 3D-printed PLA have been published so far [10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Fatigue strength of additively manufactured polylactide (PLA): effect of raster angle and non-zero mean stresses

Ezeh

Susmel

2019

International Journal of Fatigue

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As far as polymers are concerned, polylactide (PLA) is certainly the polymeric compound that is most commonly used along with commercial additive manufacturing technologies. In this context, the present paper aims to investigate the influence of manufacturing direction and superimposed static stresses on the fatigue strength of PLA 3D-printed by using the Fused Filament Fabrication technique. This was done not only by generating a large number of new experimental results, but also by re-analysing different data sets taken from the technical literature. As long as the fused deposition modelling technology is used to fabricate, flat on the build-plate, objects of PLA, the obtained results and the performed re-analyses allowed us to come to the following conclusions: (i) the influence of the manufacturing direction can be neglected with little loss of accuracy; (ii) the effect of superimposed static stresses can be quantified and assessed effectively by simply performing the fatigue assessment in terms of maximum stress in the cycle; (iii) if appropriate experiments cannot be run, AM PLA can be designed against fatigue (for a probability of survival larger than 90%) by referring to a unifying design curve having negative inverse slope equal to 5.5 and endurance limit (at =2•10 6 cycles to failure) equal to 10% of the material ultimate tensile strength.

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Fatigue behaviour of additively manufactured polylactide (PLA)

Cited by 16 publications

References 7 publications

Improving the fatigue life of printed structures using stochastic variations

Improving the fatigue life of printed structures using stochastic variations

Guidelines for 3D printed springs using material extrusion

Fatigue strength of additively manufactured polylactide (PLA): effect of raster angle and non-zero mean stresses

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