A reliable finite element procedure to simulate shear-dominated ductile fracture in large-scale, thin-walled steel structures is still evolving due primarily to the challenges in determining the fracture criterion of steel materials under complex stress states. This paper aims to examine the accuracy of the modified Gurson-Tvergaard-Needleman (GTN) model considering the shear failure in simulating ductile fracture of steel plate structures under quasi-static punch loading. The modified GTN damage models are performed by ABAQUS user defined material subroutine (VUMAT). The void related parameters and shear damage parameters of Xue’s and N-H modified GTN models are calibrated from test specimens with various geometries corresponding to different stress triaxiality and shearing conditions. The damage evolution associated with the shearing of voids in the modified GTN models has strong influences on the stress triaxiality versus equivalent plastic strain under complex stress states, especially for the shear dominated loading conditions. Based on the original GTN model, Xue’s model, and N-H modified GTN model with calibrated material parameters, a numerical comparative study examines the ductile fracture of steel non-stiffened plate and stiffened plate under punch loading. Benchmarked against the experimental studies, the numerical simulations demonstrate that the shear driven void evolution in the modified GTN model imposes significant effects on the load-displacement responses, as well as the onset and extension of ductile fracture in steel plates under punch actions. The N-H modified model with calibrated shear damage parameters shows a better correlation with the ductile fractures in steel plates observed in the experiment, than the original GTN model and Xue’s modified GTN model. As a result of this study, the modified GTN model considering the shear failure can be applied for practical applications in the crashworthiness assessment of ship collision and grounding.

This paper presents the development of a new system designed to measure the local temperature field in adiabatic shear band. Transient temperature field are simultaneously recorded by an array of 32 InSb infrared (IR) detectors and a streak camera working in visible-near infrared (VIS-NIR). Observations in IR offer a low temperature detection limit (350°C) but they are highly sensitive to uncertainty in the emissivity. Observations in VIS-NIR allow for measurement only at high temperatures (750°C) but they are less affected by uncertainty on emissivity and present a higher temperature sensitivity. By performing simultaneous measurements, it is possible to obtain data on a large temperature range with an improved accuracy at high temperature. The different sources of errors caused by uncertainty in the emissivity, spatial and temporal resolution of the detectors has been analyzed and an estimation of the total measurement uncertainty of the system is given.

Background: The heterogeneity of rectal biopsy techniques encourages us to search for a surgical and pathological standardisation of this diagnostic technique to exclude Hirschsprung’s disease. The varying amount of information on the anatomopathology report prompts us to compile a template concerning the anatomopathology report for diagnostic rectal biopsies for colleague surgeons and pathologists working on Hirschsprung’s disease. Methods: We gathered the anonymous biopsy information and its pathology information from five hospitals of all patients in which rectal biopsies were taken to diagnose Hirschsprung’s disease over two years (2020-2021). Results: 82 biopsies: 20 suction (24,4%), 31 punch (37.8%) and 31 open biopsies (37,8%) were taken. Of all biopsies 69 were conclusive (84,2%), 13 were not (15,8%). In the suction biopsy group 60% were conclusive, 40% not, for punch biopsy 87% and 13% respectively and for open biopsy 97% and 3%. Inconclusive results were due to insufficient submucosa in 6/8 suction biopsies, 4/4 punch and 0/1 open biopsies. An insufficient amount of submucosa was the reason for an inconclusive result in 6/20 cases (30%) after suction biopsy, 4/31 (12,9%) after punch biopsy and 0 cases (0%) after open biopsy. We had one case with major postoperative bleeding post suction biopsy; there were no further adverse effects after biopsy. Conclusions: Diagnostic rectal biopsies in children are safe. Non-surgical biopsies are more likely to give inconclusive results, due to less submucosa present in the specimen. Open biopsies are especially useful when previous non-surgical biopsies are inconclusive. An experienced pathologist is a key factor for the result. The anatomopathology report should specify the different layers present in the specimen, the presence of ganglion cells and hypertrophic nerve fibers, their description and a conclusion.

Based on a very fast numerical procedure for the determination of the subsurface stress field beneath frictional contacts of axisymmetric elastic bodies under arbitrary 2D oblique loading, the contact mechanical influences of loading parameters and contact profile geometry on the Smith-Watson-Topper (SWT) fatigue crack initiation parameter in elastic fretting contacts with superimposed normal and tangential oscillations are studied in detail. The efficiency of the stress calculation allows for a comprehensive physical analysis of the multi-dimensional parameter space of influencing variables. It is found that a superimposed normal oscillation of the contact can significantly increase or decrease the SWT parameter, depending on the initial phase difference and frequency ratio between the normal and tangential oscillation. Written in proper non-dimensional variables, the rounded flat punch always exhibits smaller values of the SWT parameter, compared to a full paraboloid with the same curvature, while the truncated paraboloid exhibits larger values. A small superimposed profile waviness also significantly increased or decreased the SWT parameter, depending on the amplitude and wave length of the waviness. While both the load protocol and the profile geometry can significantly alter the SWT parameter, the coupling between both influencing factors is weak.