Chapter 5: FEM Analysis of Open-Die Sinter-Forging of different Generic Shaped Preforms

The creation of acrylic dentures involves many stages. One of them is to prepare the surfaces of artificial teeth for connection with the denture plates. The teeth could be rubbed with a chemical reagent, the surface could be developed, or retention hooks could be created. Preparation of the surface is used to improve the bond between the teeth and the plate. Choosing the right combination affects the length of denture use. This work focuses on a numerical analysis of grooving. The purpose of this article is to select the shape and size of the grooves that would most affect the quality of the bond strength. Two types of grooves in different dimensional configurations were analyzed. The variables were groove depth and width, and the distance between the grooves. Finally, 24 configurations were obtained. Models were analyzed in terms of their angular position to the loading force. Finite element method (FEM) analysis was performed on the 3D geometry created, which consisted of two polymer bodies under the shear process. The smallest values of the stresses and strains were characterized by a sample with parallel grooves with the grooving dimensions width 0.20 mm, thickness 0.10 mm, and distance between the grooves 5.00 mm, placed at an angle of 90°. The best dimensions from the parallel (III) and cross (#) grooves were compared experimentally. Specimens with grooving III were not damaged in the shear test. The research shows that the shape of the groove affects the distribution of stresses and strains. Combining the selected method with an adequately selected chemical reagent can significantly increase the strength of the connection.

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Crack-Length Estimation for Structural Health Monitoring Using the High-Frequency Resonances Excited by the Energy Release during Fatigue-Crack Growth

Sensors ◽

10.3390/s21124221 ◽

2021 ◽

Vol 21 (12) ◽

pp. 4221

Author(s):

Roshan Joseph ◽

Hanfei Mei ◽

Asaad Migot ◽

Victor Giurgiutiu

Keyword(s):

Fatigue Crack ◽

Fatigue Crack Growth ◽

Crack Length ◽

Crack Growth ◽

Health Monitoring ◽

Acoustic Waves ◽

High Frequency ◽

Fem Analysis ◽

Signal Frequency ◽

Propagation Pattern

Acoustic waves are widely used in structural health monitoring (SHM) for detecting fatigue cracking. The strain energy released when a fatigue crack advances has the effect of exciting acoustic waves, which travel through the structures and are picked up by the sensors. Piezoelectric wafer active sensors (PWAS) can effectively sense acoustic waves due to fatigue-crack growth. Conventional acoustic-wave passive SHM, which relies on counting the number of acoustic events, cannot precisely estimate the crack length. In the present research, a novel method for estimating the crack length was proposed based on the high-frequency resonances excited in the crack by the energy released when a crack advances. In this method, a PWAS sensor was used to sense the acoustic wave signal and predict the length of the crack that generated the acoustic event. First, FEM analysis was undertaken of acoustic waves generated due to a fatigue-crack growth event on an aluminum-2024 plate. The FEM analysis was used to predict the wave propagation pattern and the acoustic signal received by the PWAS mounted at a distance of 25 mm from the crack. The analysis was carried out for crack lengths of 4 and 8 mm. The presence of the crack produced scattering of the waves generated at the crack tip; this phenomenon was observable in the wave propagation pattern and in the acoustic signals recorded at the PWAS. A study of the signal frequency spectrum revealed peaks and valleys in the spectrum that changed in frequency and amplitude as the crack length was changed from 4 to 8 mm. The number of peaks and valleys was observed to increase as the crack length increased. We suggest this peak–valley pattern in the signal frequency spectrum can be used to determine the crack length from the acoustic signal alone. An experimental investigation was performed to record the acoustic signals in crack lengths of 4 and 8 mm, and the results were found to match well with the FEM predictions.

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FEM analysis of water surface profile using VOF Method

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/1116/1/012112 ◽

2021 ◽

Vol 1116 (1) ◽

pp. 012112

Author(s):

Avdhesh Kumar Sharma ◽

Prashant Kumar Dixit ◽

Shashank Srivastava

Keyword(s):

Water Surface ◽

Surface Profile ◽

Fem Analysis ◽

Vof Method ◽

Water Surface Profile

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Structural and FEM analysis of heat treatment effects on mild steel

Materials Today Proceedings ◽

10.1016/j.matpr.2021.02.204 ◽

2021 ◽

Author(s):

Aaditya Srivastava ◽

Ansh Jain ◽

Shubham Rajput ◽

Hari Om Singh ◽

Bhaskar Chandra Kandpal ◽

...

Keyword(s):

Heat Treatment ◽

Mild Steel ◽

Treatment Effects ◽

Fem Analysis

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Experimental & FEM Analysis of Orthodontic Mini-Implant Design on Primary Stability

Applied Sciences ◽

10.3390/app11125461 ◽

2021 ◽

Vol 11 (12) ◽

pp. 5461

Author(s):

Elmedin Mešić ◽

Enis Muratović ◽

Lejla Redžepagić-Vražalica ◽

Nedim Pervan ◽

Adis J. Muminović ◽

...

Keyword(s):

Finite Element ◽

Three Dimensional ◽

Primary Stability ◽

Fem Analysis ◽

Implant Design ◽

Special Focus ◽

Engineering System ◽

Mini Implants ◽

Pull Out ◽

Computer Aided

The main objective of this research is to establish a connection between orthodontic mini-implant design, pull-out force and primary stability by comparing two commercial mini-implants or temporary anchorage devices, Tomas®-pin and Perfect Anchor. Mini-implant geometric analysis and quantification of bone characteristics are performed, whereupon experimental in vitro pull-out test is conducted. With the use of the CATIA (Computer Aided Three-dimensional Interactive Application) CAD (Computer Aided Design)/CAM (Computer Aided Manufacturing)/CAE (Computer Aided Engineering) system, 3D (Three-dimensional) geometric models of mini-implants and bone segments are created. Afterwards, those same models are imported into Abaqus software, where finite element models are generated with a special focus on material properties, boundary conditions and interactions. FEM (Finite Element Method) analysis is used to simulate the pull-out test. Then, the results of the structural analysis are compared with the experimental results. The FEM analysis results contain information about maximum stresses on implant–bone system caused due to the pull-out force. It is determined that the core diameter of a screw thread and conicity are the main factors of the mini-implant design that have a direct impact on primary stability. Additionally, stresses generated on the Tomas®-pin model are lower than stresses on Perfect Anchor, even though Tomas®-pin endures greater pull-out forces, the implant system with implemented Tomas®-pin still represents a more stressed system due to the uniform distribution of stresses with bigger values.

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A FEM analysis of the settlement of a tall building situated on loess subsoil

Open Engineering ◽

10.1515/eng-2020-0060 ◽

2020 ◽

Vol 10 (1) ◽

pp. 519-526

Author(s):

Krzysztof Nepelski

Keyword(s):

Fem Analysis ◽

Actual Process ◽

Linear Elastic ◽

Perfectly Plastic ◽

Modified Cam Clay ◽

Linear Behaviour ◽

Subsequent Calculation ◽

Elastic Perfectly Plastic ◽

Subsoil Model ◽

Storey Building

AbstractIn order to correctly model the behaviour of a building under load, it is necessary to take into account the displacement of the subsoil under the foundations. The subsoil is a material with typically non-linear behaviour. This paper presents an example of the modelling of a tall, 14-storey, building located in Lublin. The building was constructed on loess subsoil, with the use of a base slab. The subsoil lying directly beneath the foundations was described using the Modified Cam-Clay model, while the linear elastic perfectly plastic model with the Coulomb-Mohr failure criterion was used for the deeper subsoil. The parameters of the subsoil model were derived on the basis of the results of CPT soundings and laboratory oedometer tests. In numerical FEM analyses, the floors of the building were added in subsequent calculation steps, simulating the actual process of building construction. The results of the calculations involved the displacements taken in the subsequent calculation steps, which were compared with the displacements of 14 geodetic benchmarks placed in the slab.

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