Finite Element Analysis of Mixed-Mode I/II Fracture in Marble Using SENB Specimens

2026-03-30T15:06:00+02:00

The fracture behavior of brittle rocks, like fractures in marble, is important for various engineering applications, including mining, underground facilities, hydraulic mining, and tunneling. While most of the prior work has focused on pure Mode I loading, rock structures undergo mixed-Mode I/II loading in which fractures appear from tensile and shear stresses. This research specifically looks at mixed-Mode I/II fractures in which vertical pre-cracked single edge notched beam specimens allow for a variety of Mode mixites without the difficult construction of angled cracks. Finite element simulations in ABAQUS focused on calculating Mode I (K_I) as well as II (K_II) stress intensity factors (SIF) and T-stress, with mesh convergence ensuring accuracy. To predict fractures in polygons, the maximum tangential stress (MTS) and generalized maximum tangential stress (GMTS) criteria were used. The outcomes display that pure Mode I yields the lowest fracture load while, with Mode II contribution, it increases and reaches the peak at pure Mode II. There is an increase in the crack propagation angle with respect to the increase of Mode II dominance, displaying the effect of negative T-stress on cracking density. The methodology is single-edge notched beam (SENB) samples for the mixed-mode fracture of brittle rocks incorporating numerical simulations with fracture criteria. This gives systems for predictive modelling to work with in experimental design.

Performance Evaluation Research of Digital Twin Model of Knife Gate Based on Finite Element Analysis Under Temperature Rise

2026-07-17T11:49:15+02:00

Knife gate valves are widely used in industrial systems for regulating the flow of liquids, gases, and slurries under demanding operating conditions. Continuous exposure to elevated temperatures can cause thermal expansion, material degradation, stress accumulation, and structural deformation, reducing valve performance and increasing failure risk. This study proposes a Digital Twin-based thermo-mechanical performance evaluation framework integrated with finite element analysis (FEA) for knife gate valves under progressive thermal loading. Five operating temperature cases of 50∘C, 100∘C, 150∘C, 200∘C, and 250∘C were evaluated to characterize temperature distribution, heat flow, temperature-dependent yield strength, thermal and mechanical stress, deformation, safety factor, actuator torque, and seal pressure. The results demonstrate progressive thermo-mechanical degradation with increasing temperature. At 250∘C, the maximum induced stress reaches 246.45 MPa, exceeding the temperature-dependent yield strength of 235.2 MPa, while the safety factor decreases to 0.95 and deformation increases to 0.80682 mm. The required actuator torque increases to 1414.56 Nm, accompanied by a reduction in seal pressure to 1.069 MPa, a decline in valve health score from 100% to 55%, and a reduction in remaining useful life from 74.57 to 24.14 years. The Digital Twin consequently identifies the highest-temperature condition as a warning state, indicating increased structural and operational risk. The primary contribution of this work is the simultaneous prediction of stress, deformation, safety factor, torque, and remaining useful life within a single unified Digital Twin–FEA model.

European Journal of Computational Mechanics

Finite Element Analysis of Mixed-Mode I/II Fracture in Marble Using SENB Specimens

Performance Evaluation Research of Digital Twin Model of Knife Gate Based on Finite Element Analysis Under Temperature Rise