scholarly journals Testing Machine for Thermal Fatigue with Variable Constraint Ratio

1973 ◽  
Vol 22 (233) ◽  
pp. 110-116 ◽  
Author(s):  
Shuji TAIRA ◽  
Motoaki FUJINO ◽  
Takashi HAJI
Keyword(s):  
Thermal Fatigue ◽  
Testing Machine ◽  
Constraint Ratio

scholarly journals Fracture Load and Phase Transformation of Monolithic Zirconia Crowns Submitted to Different Aging Protocols

2016 ◽  
Vol 41 (5) ◽  
pp. E118-E130 ◽  
Author(s):  
ETP Bergamo ◽  
WJ da Silva ◽  
PF Cesar ◽  
AA Del Bel Cury
Keyword(s):  
Phase Transformation ◽  
Thermal Fatigue ◽  
Structural Reliability ◽  
Contact Point ◽  
Testing Machine ◽  
Fracture Load ◽  
Hydrothermal Aging ◽  
High Fracture ◽  
Zirconia Crowns ◽  
Monolithic Zirconia

SUMMARY Monolithic zirconia crowns have many favorable properties and may potentially be used to solve dental problems such as chipping. However, monolithic zirconia crown resistance can be affected by its phase transformation when subjected to low temperatures, humidity, and stress. This study evaluated the fracture load and phase transformation of monolithic zirconia crowns submitted to different thermal and mechanical aging tests. Seventy monolithic zirconia crowns were randomly divided into the following five groups: control, no treatment; hydrothermal aging at 122°C, two bar for one hour; thermal fatigue, 104 cycles between 5°C and 55°C, dwell time, 30 seconds; and mechanical fatigue, 106 cycles with a load of 70 N, sliding of 1.5 mm at 1.4 Hz; and combination of mechanical plus thermal fatigue. Fracture load was measured with a universal testing machine. Surface changes and fracture mode and origin were examined with a scanning electron microscope. Monoclinic phase content was evaluated by x-ray diffraction. The fracture load was analyzed using one-way analysis of variance at a level of 5%, and Weibull distribution was performed. No statistically significant differences were observed in the mean fracture load and characteristic fracture load among the groups (p>0.05). The Weibull modulus ranged from 6.2 to 16.6. The failure mode was similar for all groups with the crack origin located at the contact point of the indenter. Phase transformation was shown at different surfaces of the crown in all groups (1.9% to 8.9%). In conclusion, monolithic zirconia crowns possess high fracture load, structural reliability, and low phase transformation.

Cast Steel Tests under Thermal Fatigue Conditions

2014 ◽  
Vol 224 ◽  
pp. 105-111
Author(s):  
Adam Lipski ◽  
Stanisław Mroziński
Keyword(s):  
Experimental Research ◽  
Thermal Fatigue ◽  
Mechanical Load ◽  
Cast Steel ◽  
Testing Machine ◽  
Numerical Calculations ◽  
Test Time ◽  
Heating Chamber ◽  
Static Tests ◽  
Load Conditions

This paper presents results of experimental research and numerical calculations for thermal fatigue of G-X12CrMoVNbN9-1 martensitic cast steel. The tests were performed using hydraulic testing machine equipped with the heating chamber. The experimental research included static tests under mechanical load conditions at four temperature levels (20°C, 400°C, 550°C, 600°C) aimed at determining material characteristics needed for the numerical model. Main cyclic tests were carried out under thermal load conditions. The parameter, which was maintained at unchanged level during tests was the specimen strain ε = const = 0. The specimen temperature was changed. The numerical calculations for the same temperature change program were performed with the use of ABAQUS software. Experimentally and numerically determined stress value versus test time were compared.

scholarly journals Thermocracks®, a Specific Testing Machine for Evaluation of the Thermal Fatigue Resistance of Materials

2013 ◽  
Vol 66 ◽  
pp. 250-263 ◽  
Author(s):  
Gilles Regheere ◽  
Mathilde Collignon ◽  
Anne-Lise Cristol ◽  
Yannick Desplanques ◽  
Philippe Dufrenoy ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Thermal Fatigue ◽  
Testing Machine ◽  
Thermal Fatigue Resistance

Testing Machine at Watertown Arsenal, Mass

1886 ◽  
Vol 22 (548supp) ◽  
pp. 8753-8754
Author(s):  
J. E. Howard
Keyword(s):  
Testing Machine

Parametric Study of Damping Characteristics of Magneto-Rheological Damper: Mathematical and Experimental Approach

2020 ◽  
Vol 15 (3) ◽  
pp. 37-48
Author(s):  
Zubair Rashid Wani ◽  
Manzoor Ahmad Tantray
Keyword(s):  
Structural Control ◽  
Research Work ◽  
Testing Machine ◽  
Input Voltage ◽  
Damping Coefficient ◽  
Control Technique ◽  
Damping Force ◽  
Active Devices ◽  
Active Structural Control ◽  
Magneto Rheological

The present research work is a part of a project was a semi-active structural control technique using magneto-rheological damper has to be performed. Magneto-rheological dampers are an innovative class of semi-active devices that mesh well with the demands and constraints of seismic applications; this includes having very low power requirements and adaptability. A small stroke magneto-rheological damper was mathematically simulated and experimentally tested. The damper was subjected to periodic excitations of different amplitudes and frequencies at varying voltage. The damper was mathematically modeled using parametric Modified Bouc-Wen model of magneto-rheological damper in MATLAB/SIMULINK and the parameters of the model were set as per the prototype available. The variation of mechanical properties of magneto-rheological damper like damping coefficient and damping force with a change in amplitude, frequency and voltage were experimentally verified on INSTRON 8800 testing machine. It was observed that damping force produced by the damper depended on the frequency as well, in addition to the input voltage and amplitude of the excitation. While the damping coefficient (c) is independent of the frequency of excitation it varies with the amplitude of excitation and input voltage. The variation of the damping coefficient with amplitude and input voltage is linear and quadratic respectively. More ever the mathematical model simulated in MATLAB was in agreement with the experimental results obtained.

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