Additive manufacturing technologies have numerous advantages over conventional technologies; nevertheless, their production process can lead to high residual stresses and distortions in the produced parts. The use of numerical simulation models is presented as a solution to predict the deformations and residual stresses resulting from the printing process. This study aimed to predict the tensions and distortions imposed in the gear repair process by directed energy deposition (DED). First, the case study proposed by National Institute of Standards and Technology (NIST) was analyzed to validate the model and the numerically obtained results. Subsequently, a parametric study of the influence of some of the parameters of DED technology was carried out. The results obtained for the validation of the NIST benchmark bridge model were in agreement with the results obtained experimentally. In turn, the results obtained from the parametric study were almost always in line with what is theoretically expected; however, some results were not very clear and consistent. The results obtained help to clarify the influence of certain printing parameters. The proposed model allowed accounting for the effect of residual stresses in calculating the stresses resulting from gear loading, which are essential data for fatigue analysis. Modeling and simulating a deposition process can be challenging due to several factors, including calibrating the model, managing the computational cost, accounting for boundary conditions, and accurately representing material properties. This paper aimed to carefully address these parameters in two case studies, towards reliable simulations.
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http://dx.doi.org/10.3390/ma16093549 | DOI Listing |
BMC Public Health
January 2025
Center for Global Health, Weill Cornell Medicine, 402 East 67 Street, 2 Floor, New York, NY, 10065, USA.
Background: Uncontrolled hypertension is the leading modifiable risk factor for cardiovascular disease mortality and remains high in low-middle income countries like Haiti. Barriers and facilitators to achieving hypertension control in urban Haiti remain poorly understood. Elucidating these factors could lead to development of successful interventions.
View Article and Find Full Text PDFSci Rep
January 2025
School of Civil Engineering and Architecture, Anhui University of Science and Technology, Huainan, 232001, Anhui, China.
To investigate the changes in the strength and deformation of the blast load-damaged sandstone roof plate under cyclic loading and unloading conditions at different confining pressures, a triaxial loading device was used to carry out graded cyclic unloading tests on specimens with different degrees of damage, and the test results were summarized. The effects of blast-load-induced damage, confining pressure and loading stage on the strength, cohesion, internal friction angle, residual strain and volumetric strain were analyzed. (1) Compared with that of the undamaged specimen at a confining pressure of 0 MPa, the peak stress reductions in the vibration-damaged and blast-damaged specimens were 4.
View Article and Find Full Text PDFInt J Surg Case Rep
December 2024
Department of Urology, Faculty of Medicine, Airlangga University, Dr. Soetomo General Academic Hospital, Surabaya, Indonesia.
Introduction: Primary bladder neck obstruction (PBNO) is a rare but significant cause of BOO and LUTS in females, with unclear etiology involving theories of fibrotic narrowing, tissue hyperplasia, or muscle abnormalities. Due to nonspecific symptoms, PBNO diagnosis remains challenging, and optimal surgical treatment needs to be better defined.
Case Presentation: We report two cases of females in their 50s with recurrent urinary retention managed by indwelling catheters.
Eur J Psychotraumatol
December 2025
Research and Knowledge Centre, Danish Veterans Centre, Ringsted, Denmark.
A number of studies have tested the factor structure of the suggested ICD-11 symptom criteria for PTSD and complex PTSD (CPTSD) across various trauma populations, finding support for two different models in line with the ICD-11 theoretical rationale. Here, we aim to explore the factor structure of the Danish version of the International Trauma Questionnaire (ITQ) by testing two alternative factor models that have previously gained support in a large sample of treatment-seeking veterans. Treatment-seeking Danish soldiers and veterans ( = 599) recruited from the Military Psychology Department in the Danish Defence completed the International Trauma Questionnaire (ITQ).
View Article and Find Full Text PDFNat Commun
January 2025
The Institute of Technological Sciences, Wuhan University, Wuhan, China.
Flexible perovskite solar cells (F-PSCs) are appealing for their flexibility and high power-to-weight ratios. However, the fragile grain boundaries (GBs) in perovskite films can lead to stress and strain cracks under bending conditions, limiting the performance and stability of F-PSCs. Herein, we show that the perovskite film can facilely achieve in situ bifacial capping via introducing 4-(methoxy)benzylamine hydrobromide (MeOBABr) as the precursor additive.
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