A robotic chewing simulator supplying six-axis mandibular motion, high occlusal force, and a saliva environment for denture tests

2021 ◽  
pp. 095441192110056
Author(s):  
Wenlong Qin ◽  
Ming Cong ◽  
Dong Liu ◽  
Xiang Ren
Keyword(s):  
Flow Rate ◽  
Failure Modes ◽  
Testing Machine ◽  
Dynamic Test ◽  
Dynamic Tests ◽  
Occlusal Force ◽  
Static Tests ◽  
Static Test ◽  
Axis Parallel

Six-axis motion is essential for the evaluation of the wear failure modes of dental prostheses with complete teeth morphologies, and a high occlusal force capacity is vital for static clenching and dynamic bruxism. Additionally, the saliva environment influences abrasive particles and crack growth. The present research was aimed at the development of a six-axis masticatory and saliva simulator with these capacities. The masticatory simulator was designed based on a six-axis parallel mechanism, and the saliva simulator consisted of a saliva circuit and a temperature control loop. A control system of the masticatory and saliva simulators was constructed. The operating interface includes a centric occlusal position search, a static test, a dynamic test, a saliva supply, and data reporting. The motion and force performances of the masticatory simulator were evaluated. The flow rate and temperature change of the saliva simulator were calculated. For the occlusal position-searching, the driving amplitude is linear with the moving variables during minor one-axis motion. For the static tests, the force capacity of the driving chain is 3540 N, while for the dynamic tests, the force capacity is 1390 N. The flow rate of the saliva is 0.18–51.84 mL/min, and the saliva can effectively wet the prosthesis without the risk of overflow. Moreover, the saliva temperature can increase from room temperature (23°C) to body temperature (37°C) in about 6 min. The proposed DUT-2 simulator with six-axis motion, high force, and a salvia environment provides an in vitro testing approach to validate numerical simulation results and explain the clinical failure modes of prostheses. The centric occlusal position-searching, static tests, and dynamic tests could therefore be executed using a single testing machine. Moreover, the proposed device is more compact than previously reported six-axis masticatory simulators, including the Bristol simulator and DUT-1 simulator.

The Behaviour Of Square Sandwich Panel Part I: Under Static Loading

2012 ◽  
Author(s):  
Amran Alias ◽  
Nor Azlan Ahmad Nor ◽  
Mohd Radzai Said
Keyword(s):  
Static Loading ◽  
Sandwich Panel ◽  
Failure Modes ◽  
Dynamic Tests ◽  
Concentrated Load ◽  
Static Tests ◽  
Static Test ◽  
Pu Foam ◽  
Materials Used ◽  
Observed Damage

Kajian mengenai panel apit segi empat terdiri daripada dua bahagian. Dalam bahagian pertama, prestasi dan kelakuan panel apit segi empat yang dikenakan beban statik dikaji. Panel apit ini sokong oleh unit sokongan dan dikenakan bebanan dibahagian tengahnya dengan menggunakan penakuk separa bulat dan penakuk rata. Panel apit spesifik yang digunakan untuk projek ini ialah kepingan keluli lembut, foam PVC yang dinamakan R55 dan teras daripada busa poli uretana (PU). Tujuan kajian ini adalah untuk mendapatkan bukti secara eksperimen tentang corak serta jenis kegagalan panel apit segi empat yang dikenakan beban tumpu di tengah–tengahnya dan disokong pada setiap bucunya. Selepas ujian statik dilakukan, lengkungan bagi setiap panel ditentukan. Hubungan antara pertumbuhan kerosakan dan kelakuan kerosakan semasa ujian statik ke atas panel dikaji. Dalam bahagian kedua, ujian dinamik dijalankan untuk menentukan prestasi, kelakuan, dan kesan bagi jenis busa serta hubungan antara tenaga masukan daripada ujian statik dan dinamik. Kata kunci: Panel apit segi empat, foam PU, foam PVC (R55), mod kegagalan This series of papers on behaviour of square sandwich panel consists of two parts. In part I, the performance and behaviour of the square sandwich panel under static loading was first examined. The sandwich panel was centrally loaded by using hemispherical and flat indenters on their respective support units. The panel materials used specifically for this project are mild steel skin and PVC foam namely R55 and polyurethane (PU) foam cores. The aim of this study is to obtain experimental evidence of the failure modes of square sandwich panels under concentrated load at the centre of panels, simply supported at the four edge corners for the square panel. After static tests, the whole curves for each panel were determined. The relation between the observed damage evelopment, the property of degradation during the static test of the panels was investigated. In part II, the dynamic tests will be conducted in order to determine the performance, behaviour, effect of foam’s type and the correlation between input energy from static and dynamic tests. Key words: Square sandwich panel, PU foam, PVC foam (R55), failure modes

Biocompatibility and Cytotoxic Evaluation of New Sorbent Cartridges for Blood Hemoperfusion

2018 ◽  
Vol 46 (3) ◽  
pp. 187-195 ◽  
Author(s):  
Diego Pomarè Montin ◽  
Ghada Ankawi ◽  
Anna Lorenzin ◽  
Mauro Neri ◽  
Carlotta Caprara ◽  
...  
Keyword(s):  
Adverse Reactions ◽  
Dynamic Test ◽  
Optimal Level ◽  
In Vitro Testing ◽  
Dynamic Tests ◽  
Cytotoxic Effects ◽  
Static Test ◽  
Static And Dynamic Tests ◽  
Cell Medium

Background/Aims: The use of adsorption cartridges for hemoperfusion (HP) is rapidly evolving. For these devices, the potential induced cytotoxicity is an important issue. The aim of this study was to investigate potential in vitro cytotoxic effects of different sorbent cartridges, HA130, HA230, HA330, HA380 (Jafron, China), on U937 monocytes. Methods: Monocytes were exposed to the sorbent material in static and dynamic manners. In static test, cell medium samples were collected after 24 h of incubation in the cartridges. In dynamic test, HP modality has been carried out and samples at 30, 60, 90, and 120 min were collected. Results: Compared to control samples, there was no evidence of increased necrosis or apoptosis in monocytes exposed to the cartridges both in the static and dynamic tests. Conclusion: Our in vitro testing suggests that HA cartridges carry an optimal level of biocompatibility and their use in HP is not associated with adverse reactions or signs of cytotoxicity.

Experimental Assessment of the Dynamic Behavior of Polyolefin Thermoplastic Hot Melt Adhesive

2018 ◽  
Author(s):  
Raffaele Ciardiello ◽  
Andrea Tridello ◽  
Luca Goglio ◽  
Giovanni Belingardi
Keyword(s):  
Failure Modes ◽  
Industrial Applications ◽  
Lap Joints ◽  
Adhesive Joints ◽  
Dynamic Tests ◽  
Cohesive Failure ◽  
Static Tests ◽  
Piping Systems ◽  
The Many ◽  
Hot Melt

In the last decades, the use of adhesives has rapidly increased in many industrial fields. Adhesive joints are often preferred to traditional fasteners due to the many advantages that they offer. For instance, adhesive joints show a better stress distribution compared to the traditional fasteners and high mechanical properties under different loading conditions. Furthermore, they are usually preferred for joining components made of different materials. A wide variety of adhesives is currently available: thermoset adhesives are generally employed for structural joints but recently there has been a significant increment in the use of thermoplastic adhesives, in particular of the hot-melt adhesives (HMAs). HMAs permit to bond a large number of materials, including metal and plastics (e.g., polypropylene, PP), which can be hardly bonded with traditional adhesives. Furthermore, HMAs are characterized by a short open time and, therefore, permit for a quick and easy assembly process since they can be easily spread on the adherend surfaces by means of a hot-melt gun and they offer the opportunity of an ease disassembling process for repair and recycle. For all these reasons, HMAs are employed in many industrial applications and are currently used also for bonding polypropylene and polyolefin piping systems. In the present paper, the dynamic response of single lap joints (SLJ) obtained by bonding together with a polyolefin HMA two polypropylene substrates was experimentally assessed. Quasi-static tests and dynamic tests were carried out to investigate the strain rate effect: dynamic tests were carried out with a modified instrumented impact pendulum. Relevant changes in the joint performance have been put in evidence. Failure modes were finally analysed and compared. A change in the failure mode is experimentally found: in quasi-static tests SLJ failed due to a cohesive failure of the adhesive, whereas in dynamic tests the SLJ failed due to an interfacial failure, with a low energy absorption.

Effect of Loading Rate on Tensile Properties of Automotive Steel Sheet

2013 ◽  
Vol 690-693 ◽  
pp. 211-217
Author(s):  
Jin Gui Qin ◽  
Fang Yun Lu ◽  
Yu Liang Lin ◽  
Xue Jun Wen
Keyword(s):  
Strain Rate ◽  
Testing Machine ◽  
Structural Response ◽  
Tensile Tests ◽  
Dynamic Tests ◽  
Static Tests ◽  
Split Hopkinson Tensile Bar ◽  
Axial Tensile ◽  
Static Tensile ◽  
Cook Model

Results of uni-axial tensile loading of three automotive steels at different strain rates (0.0011–3200s-1) are reported here. Quasi-static tensile tests were performed under the strain rate of 1.1×10-3 s-1 using an electromechanical universal testing machine, whereas dynamic tests were carried out under the strain rate in the range of 1100 to 3200 s-1 using a Split Hopkinson Tensile Bar apparatus. Based on the experimental results, the material parameters of widely used Johnson–Cook model which described the strain rate and temperature-dependent of mechanical behaviour were determined. The experiments show that strain-rate hardening is superior to thermal softening: yield stresses, tensile strength, deformation, and energy dissipation increase with the strain rate from quasi-static tests to dynamic tests. The Johnson–Cook model can describe the behaviour of these steels and provides the opportunity to study the material and structural response.

scholarly journals Viscoelastic Parameters of Asphalt Mixtures Identified in Static and Dynamic Tests

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2084 ◽  
Author(s):  
Piotr Mackiewicz ◽  
Antoni Szydło
Keyword(s):  
Permanent Deformation ◽  
Asphalt Mixture ◽  
Dynamic Test ◽  
Asphalt Mixtures ◽  
Rheological Parameters ◽  
Dynamic Tests ◽  
Static Test ◽  
Viscoelastic Parameters ◽  
Static Creep ◽  
Asphalt Content

We present two methods used in the identification of viscoelastic parameters of asphalt mixtures used in pavements. The static creep test and the dynamic test, with a frequency of 10 Hz, were carried out based on the four-point bending beam (4BP). In the method identifying viscoelastic parameters for the Brugers’ model, we included the course of a creeping curve (for static creep) and fatigue hysteresis (for dynamic test). It was shown that these parameters depend significantly on the load time, method used, and temperature and asphalt content. A similar variation of parameters depending on temperature was found for the two tests, but different absolute values were obtained. Additionally, the share of viscous deformations in relation to total deformations is presented, on the basis of back calculations and finite element methods. We obtained a significant contribution of viscous deformations (about 93% for the static test and 25% for the dynamic test) for the temperature 25 °C. The received rheological parameters from both methods appeared to be sensitive to a change in asphalt content, which means that these methods can be used to design an optimal asphalt mixture composition—e.g., due to the permanent deformation of pavement. We also found that the parameters should be determined using the creep curve for the static analyses with persistent load, whereas in the case of the dynamic studies, the hysteresis is more appropriate. The 4BP static creep and dynamic tests are sufficient methods for determining the rheological parameters for materials designed for flexible pavements. In the 4BP dynamic test, we determined relationships between damping and viscosity coefficients, showing material variability depending on the test temperature.

Experimental Investigation and Finite Element Analysis of the Inversion of Capped End Frusta as Impact Energy Absorbers

2004 ◽  
Author(s):  
A. A. N. Aljawi ◽  
A. A. A. Alghamdi ◽  
T. M. N. Abu-Mansour
Keyword(s):  
Experimental Investigation ◽  
Finite Element ◽  
Testing Machine ◽  
Dynamic Test ◽  
Element Analysis ◽  
Static Tests ◽  
Qualitative Dynamic ◽  
Finite Element Package ◽  
Energy Absorbers ◽  
Deformation Modes

In this paper, an innovative mode of deformation of the frusta is presented and discussed in details. A full experimental investigation for the quasi-static axial inversion of right circular frusta is given. The experimental work includes studying the effect of frusta wall thickness, angle of frusta and material type on the inversion of the frusta. The quasi-static tests were conducted on an Instron Universal testing machine and qualitative dynamic test were carried using Drop Hammer Facility. Finite element (FE) modeling of the inversion mode is carried out by using ABAQUS FE package. Analysis of the deformation modes is examined using a non-linear model of the finite element package. The FE findings are reported and modes of deformation during the inversion of aluminum frusta are described under quasi-static and dynamic cases. Furthermore, a good agreement is reported between the finite element force histories and the experimental results.

scholarly journals Dynamic and Quasi-Static Grade Crossing Collision Tests

2009 ◽  
Author(s):  
Michelle Mu¨hlanger ◽  
Patricia Llana ◽  
David Tyrell
Keyword(s):  
Energy Absorption ◽  
Impact Load ◽  
Dynamic Test ◽  
Full Scale ◽  
Structural Deformation ◽  
Longitudinal Deformation ◽  
Static Tests ◽  
Static Test ◽  
Grade Crossing ◽  
The Impact

To support the development of a proposed rule [1], a full-scale dynamic test and two full-scale quasi-static tests have been performed on the posts of a state-of-the-art (SOA) end frame. These tests were designed to evaluate the dynamic and quasi-static methods for demonstrating energy absorption of the collision and corner posts. The tests focused on the collision and corner posts individually because of their critical positions in protecting the operator and passengers in a collision where only the superstructure, not the underframe, is loaded. There are many examples of collisions where only the superstructure is loaded. For the dynamic test, a 14,000-lb cart impacted a standing cab car at a speed of 18.7 mph. The cart had a rigid striking surface in the shape of a coil mounted on the leading end that concentrated the impact load on the collision post. During the dynamic test the collision post deformed approximately 7.5 inches, and absorbed approximately 137,000 ft-lbs of energy. The SOA collision post was successful in preserving space for the operators and the passengers. For the quasi-static test of the collision post, the collision post was loaded in the same location and with the same fixture as the dynamic test. The post absorbed approximately 110,000 ft-lb of energy in 10 inches of permanent, longitudinal deformation. For the quasi-static test of the corner post, the post was loaded at the same height as the collision post, with the same fixture. The corner post absorbed 136,000 ft-lb of energy in 10 inches of permanent, longitudinal deformation. The series of tests was designed to compare the dynamic and quasi-static methods for measuring collision energy absorption during structural deformation as a measure of crashworthiness. When properly implemented, either a dynamic or quasi-static test can demonstrate the crashworthiness of an end frame.

Effect of Different Implant-Abutment Connection Materials on the Fracture Resistance of Zirconia Abutments

2020 ◽  
Vol 46 (2) ◽  
pp. 88-92 ◽  
Author(s):  
Mohammed AlAmar ◽  
Fawaz Alqahtani
Keyword(s):  
Failure Modes ◽  
Static Load ◽  
Dynamic Test ◽  
In Vitro Study ◽  
Visual Assessment ◽  
Apical Part ◽  
Size Estimation ◽  
Sample Distribution ◽  
Group B

The aim of the present in vitro study was to assess the modes of failures under static load among titanium (Ti) and 1- and 2-piece zirconia abutments. The 1- and 2-piece zirconia abutment specimens were fabricated from prescanned Ti abutments. Twenty-one implant abutments and 21 implant replicas were equally divided into 3 groups as follows: (a) Group 1 (Titanium group); (b) Group 2 (1-piece zirconia abutment group); and (c) Group 3: 2-piece zirconia abutment group). A 250 000-cycle linear fatigue load ranging between 10 N and 210 N was applied to all specimens using an all-electric dynamic test instrument. The specimens were loaded until they fractured. In all groups, assessment of mode of fracture was done on visual assessment by a trained and calibrated investigator. Prior sample-size estimation was performed; and sample distribution was assessed using the Kolmogorov and Shapiro tests. Screw fracture (n = 7) and abutment bending at the apical part (n = 7) occurred in the Ti group. In the 1-piece zirconia group, screw and abutment fractures occurred in 7 and 7 cases, respectively. In the 2-piece zirconia screw fracture (n = 7) above the Ti zirconia junction (transgingival segment) and abutment fracture (n = 7) were determined as the failure modes. In vitro, the 1-piece zirconia abutments are more fracture resistant than titanium and 2-piece zirconia abutments. From a clinical perspective, further studies are needed to determine the minimum static load value required to induce fracture of the 1- and 2-piece zirconia abutments.

scholarly journals In Vitro Comparison of Modes of Failures among Titanium and One- and Two-piece Zirconia Abutment under Static Load

2020 ◽  
Vol 14 (01) ◽  
pp. 157-160 ◽  
Author(s):  
Fawaz Alqahtani ◽  
Mohammed AlAmar
Keyword(s):  
Failure Modes ◽  
Static Load ◽  
Dynamic Test ◽  
Apical Part ◽  
Implant Abutments ◽  
Group A ◽  
Group 3 ◽  
Group 2 ◽  
The One

Abstract Objectives The objective was to assess modes of failures under static load (SL) among titanium (Ti) and one- and two-piece zirconia abutment (ZA) in vitro. Materials and Methods The Ti abutments were digitally scanned for the fabrication of the one- and two-piece zirconia abutment specimens. This was done to standardize the design of the one-piece abutment and make it the blueprint of the Ti abutment. Twenty-one implant abutments and 21 implant replicas were categorized into three groups as follows: group 1 (Titanium group), group 2 (one-piece ZA group), and group 3 (two-piece ZA group). A 250K-cycle, linear fatigue-load, reaching 10 to 210 Newton (N), was put on all specimens using an all-electric dynamic test instrument and the specimens were loaded until fracture. Statistical Analysis Assessment of mode of fracture among the groups was done visually. Significance was based below 0.05. Results Screw fracture (n = 7) and abutment bending at the apical part (n = 7) occurred in the Ti group. In the one-piece zirconia group, screw and abutment fractures occurred in seven and seven cases, respectively. In the two-piece zirconia group, screw fracture (n = 7) above the Ti zirconia junction (transgingival segment) and abutment fracture (n = 7) were determined as the failure modes. Conclusion In conclusion, all abutments underwent failures under SL in vitro; and the mode of failure modes varied among the different abutment designs used.

scholarly journals Análisis de Gases del Motor de un Vehículo a través de Pruebas Estáticas y Dinámicas. //Analysis of Gases of the Engine of a Vehicle through Static and Dynamic Tests.

Ciencia Unemi ◽  
2018 ◽  
Vol 11 (28) ◽  
pp. 97-108
Author(s):  
Juan Carlos Rocha-Hoyos ◽  
Danilo Zambrano ◽  
Ángel Portilla ◽  
German Erazo ◽  
Guido Torres ◽  
...  
Keyword(s):  
Dynamic Test ◽  
Test System ◽  
Injection System ◽  
Normal Operation ◽  
Dynamic Tests ◽  
Engine Emissions ◽  
Static Test ◽  
El Sistema ◽  
Static And Dynamic Tests ◽  
The City

El presente artículo tuvo como objetivo analizar las emisiones del motor de encendido provocado por medio de protocolos internacionales para la evaluación de la variabilidad entre las pruebas estáticas y dinámicas. Las respectivas pruebas de laboratorio se realizaron a una altura sobre los 2810 msnm., en la ciudad de Quito-Ecuador. El vehículo experimentado fue un Nissan Sentra 1.6 L., sometido a pruebas estática (ralentí; 2500 rpm), y dinámica (ASM50/15, ASM25/25, IM 240). Se concluye que el sistema de inyección del vehículo trabaja de forma incorrecta en la prueba estática, debido a que el factor lambda fluctúa entre 1.18 y 1.79 lo que afecta la operación normal del motor por empobrecimiento de la mezcla; mientras que en el sistema de prueba dinámico se acerca a la condición del factor lambda 1 parámetro ideal para la formación de la mezcla estequiométrica. La estimación de los factores de emisión fue: CO de 0.58 gr/km, HC de 0.01006 gr/km y el NOx en 0.09 gr/km. AbstractThe objective of this article was to analyze the ignition engine emissions caused by international protocols for the evaluation of the variability between static and dynamic tests. The respective laboratory tests were performed at an altitude of 2810 m above sea level in the city of Quito-Ecuador. The vehicle experienced was a Nissan Sentra 1.6 L., subjected to tests static (idle; 2500 rpm), and dynamic (ASM 50/15, ASM 25/25, IM 240). It is concluded that the injection system of the vehicle works incorrectly in the static test, because the lambda factor fluctuates between 1.18 and 1.79 which affects the normal operation of the engine due to impoverishment of the mixture; while in the dynamic test system the lambda factor 1 condition is approached ideally for the formation of the stoichiometric mixture. The estimation of the emission factors was: CO of 0.58 g/km, HC of 0.01006 g/km and NOx in 0.09 g/km.

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