Novel double edge-cracked tensile ring test for experimental and numerical mixed mode I + II fracture study of lightweight styrene acrylonitrile (SAN) foam with closed cell structure
Artykuł w czasopiśmie
MNiSW
140
Lista 2024
| Status: | |
| Autorzy: | Aliha M. R. M., Darvish M. Ghahramani, Choupani Naghdali, Lahe Peyman, Bedir Fevzi, Sadowski Tomasz |
| Dyscypliny: | |
| Aby zobaczyć szczegóły należy się zalogować. | |
| Rok wydania: | 2025 |
| Wersja dokumentu: | Drukowana | Elektroniczna |
| Język: | angielski |
| Wolumen/Tom: | 329 |
| Numer artykułu: | 111634 |
| Strony: | 1 - 26 |
| Impact Factor: | 5,3 |
| Web of Science® Times Cited: | 0 |
| Scopus® Cytowania: | 0 |
| Bazy: | Web of Science | Scopus |
| Efekt badań statutowych | NIE |
| Materiał konferencyjny: | NIE |
| Publikacja OA: | NIE |
| Abstrakty: | angielski |
| Styrene acrylonitrile (SAN) is a commercial lightweight and low-density foam material that is utilized as the core of sandwich panels in marine and aerospace industries. However, there is no data for determining the properties of crack resistance and fracture toughness of this material in the literature. Using a novel ring double edge center cracked sample subjected to diametral tensile pin loading, the mixed mode tensile-shear (I/II mode) fracture response of SAN foam is characterized experimentally in the current research. Microstructural analyses showed that the investigated SAN foam has a closed cell structure wıth average cell size and wall thickness of 400 and 15 μm, respectively. The dimensionless forms of stress-intensity-factors (SIFs) for the deformation modes I and II (denoted by YI and YII) were obtained for the diametral tensile cracked ring (DTCR) by modeling the specimen in the ABAQUS code for various loading situations and geometries of ring. The state of mode I/II mixity can be easily controlled in the DTCR sample by setting the direction of the center crack with respect to the line of applied pin-loading that varies from zero (for pure mode I) to typically about 60° (for pure mode II). Several cracked ring samples with different inner radius of ring and different crack lengths were loaded by tensile pin loading at two loading speeds. The test data revealed that the novel proposed DTCR sample is a suitable testing specimen for exploring the mixed-mode I/II fracture behavior of the SAN foam material. Such test method can provide full range I/II mixed mode fracture data for the SAN foam, in which till now there is no data for characterizing the resistance of cracking of this type of foam in the literature. The obtained results confirmed that by increasing the inner radius of the ring, the mixed mode I/II fracture envelope of SAN foam decreases for all mode mixities. Also, the I/II mode resistance envelopes were reduced by increasing the loading rate. The critical SIF values for the tested SAN foam were reduced with switch of mode mixity from mode I to mode II such that the mode II over mode I fracture toughness ratio was obtained approximately 0.5. The work of fracture (Wf) was also increased by decreasing the inner ring radius and moving from mode I to mode II. The relationship between the effective fracture toughness and work of fracture as well as the relationship between modes I and II fracture toughness values (KIc and KIIc) and the strain energy release rate for modes I and II conditions (i.e., GIc and GIIc) was also investigated for the SAN foam. An index proposed as “toughness to density ratio, (KIc/ρ and KIIc/ρ) for both tensile and shear loading modes demonstrated that the SAN foam ranked well among common and well-known polymeric foams such as PUR, PVC and PIR. |
