PSI - Issue 12

Lorenzo Bergonzi et al. / Procedia Structural Integrity 12 (2018) 392–403 Lorenzo Bergonzi / Structural Integrity Procedia 00 (2018) 000 – 000

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*Please note that in the case of PVC tests, crosshead speed was set to 2 mm/min, while in all other tests it is 5 mm/min. In addition, only three equivalent specimen per orientation were tested due to a lack of raw material. Statistically speaking, the number of samples for the two series of data is different, influencing parameters such as standard deviation. It should be noted that the values obtained using PVC present percentage variations with respect to the standard specimens similar to those presented in Table 7: it is noted that compared to the ABS, PVC is more influenced by the different orientation, presenting significantly different mechanical properties between 0 ° and 90 °. Moreover, the data at 90 ° have a slightly higher variability than those at 0°. It should be noted that in the case of the specimen printed by AM, the difference between displacement of the crosshead for the two geometries is particularly evident. It is thought that the increase is due, in addition to the previously mentioned sliding, to a slight crushing of the filaments of printed material at the contact between the specimen and the sides of the fixture seat: 100% filling is in fact only nominal and actually there is still space between two adjacent deposed filaments. As the imposed load increases, the voids in the immediate vicinity of the side of the specimen determine an area with greater yield that causes a partial settlement of the contact zone of the specimen thus enhancing the relative sliding effect. References ASTM International, 1999. ASTM D 638-99: Standard Test Method for Tensile Strength of Plastics. In: Annual Book of ASTM Standards. West Conshohocken: s.n. Frost & Sullivan, 2016. Latest Trends in the Material Testing Market. [Online] Available at: https://ww2.frost.com/frost-perspectives/latest-trends-material-testing-market/ Husain, A., Sehgal, D. K., & Pandey, R. K., 2004. An inverse finite element procedure for the determination of constitutive tensile behavior of materials using miniature specimen.. Computational Materials Science, 31(1-2), pp. 84-92. Kumar, K. et al., 2014. Use of miniature tensile specimen for measurement of mechanical properties. Procedia Engineering, Volume 86, pp. 899-909. Kumar, K. et al., 2016. Optimisation of thickness of miniature tensile specimens for evaluation of mechanical properties. Materials Science and Engineering, Volume 675, pp. 32-43. Lim, W. & Kim, H. K., 2013. Design and development of a miniaturised tensile testing machine. Global Journal of Engineering, Volume 15, pp. 48-53. Liu, H. et al., 2017. A comprehensive solution to miniaturized tensile testing: Specimen geometry optimization and extraction of constitutive behaviors using inverse FEM procedure. Fusion Engineering and Design, Volume 121, pp. 188-197. Nicoletto G., 2017. A novel test method for the fatigue characterization of metal powder bed fused alloys. Procedia Structural Integrity, Volume 7, pp. 67-74. Rodríguez, J. F., Thomas, J. P., & Renaud, J. E., 2003. Mechanical behavior of acrylonitrile butadiene styrene (ABS) fused deposition materials. Experimental investigation. Rapid Prototyping Journal, 7(3), pp. 148-158.