Experimental and theoretical investigation of mixed-mode I/II and I/III fracture behavior of PUR foams using a novel strain-based criterion

A deep learning (DL) approach is implemented to determine the dimensionless stress intensity factors of mode‐I (YI) and mode‐III (YIII), as well as the normalized T‐stress (T*) of the edge notch disk bend specimen. The deep neural network (DNN) method as the DL approach is used to model the relationship between the geometry parameters of the specimen a/t, S/R, and β as inputs, and YI, YIII, and T* as output variables. To this end, three datasets consisting of 176, 176, and 123 finite element method data points from the previous studies are extracted for YI, YIII, and T*, respectively. The developed DNN models predicted the YI, YIII, and T* with correlations of 0.97003, 0.96918, and 0.97047, respectively. Then partial dependence plot is performed to determine the relationship between YI, YIII, and T* and the geometry parameters, which is useful in predicting and optimizing YI, YIII, and T*.

Section: Introductionmentioning

confidence: 99%

Using deep learning method to predict dimensionless values of stress intensity factors and T‐stress of edge notch disk bend (ENDB) specimen

Hassani Niaki,

Pashaian

2024

“…The predictions of compression-shear failure mechanism of cracked rock mass are strongly related not only to the K-T parameters at the crack tip but also to the selection of available fracture criteria. [62][63][64] Generally, the fracture criteria proposed by most researchers can be categorized into stress-based criteria (such as the maximum tangential stress [MTS] criterion and its modified forms [64][65][66] ), strain-based criteria (such as MTSN criterion and its modified forms 67,68 ), and energy-based criteria (such as the average strain energy density [ASED] criterion 69,70 and the maximum energy release rate criterion [G-criterion] 71 ). Compared with strain-based criteria, the form of stress-based criteria is simpler.…”

Section: Introductionmentioning

confidence: 99%

Study on the global stress field of the rock mass under compression and shear considering three kinds of crack parameters

Zhu

Liu

et al. 2023

The mechanical behavior of the cracked rock mass is controlled by the crack initiation and propagation under compression and shear. The key to predicting the wing crack initiation angle is to correctly describe the distribution of the stress field at the crack tip. First, the previous studies are reviewed, and their inadequacies are discussed in detail. Next, according to the experimental results, three kinds of crack parameters (i.e., geometry, strength, and deforma-

“…Some experimental results were assessed by employing analytical failure criteria available in the literature. 17,18 Further, Shahbazian et al 19 carried out Mixed-Mode I/II and I/III fracture tests on a rigid PUR foam with a density of 40 kg/m 3 . Forty ENDB specimens were tested under the above loading conditions.…”

Section: Introductionmentioning

confidence: 99%

Fracture toughness of a rigid polyurethane foam: experimental and numerical investigation by varying the specimen sizes

Vantadori

Carpinteri

Cerioni

et al. 2023

In the present paper, the fracture toughness of a polyurethane (PUR) foam (manufactured by Necumer GmbH, Germany, under the commercial designation Necuron 651) is experimentally and numerically investigated in order to examine its dependence on the specimen sizes. As a matter fact, to the best knowledge of the present authors, such an analysis is still missing in the technical literature. To perform the experimental campaign, notched PUR foam beams, with different geometrical sizes, are tested under three‐point bending loading, and the Modified Two‐Parameter Model (recently proposed by some of the present authors) is employed to measure the fracture toughness. Subsequently, such an experimental campaign is numerically simulated by applying a micromechanical model, implemented in a non‐linear finite element homemade code. Finally, the results obtained are compared with some experimental data available in the literature, related to the same PUR foam.