Resistance welding � Destructive testing of welds � Method for the fatigue testing of multi-spot-welded specimens

Through INSTRON1304 electric hydraulic servo fatigue testing machine, the fatigue experiment of soil-cement is done, and the ultrasonic velocity of soil-cement under dynamic loading is obtained. The results show the ultrasonic wave velocity through the cemented soil samples free surface obviously attenuates as the cycles of the dynamic loading increases. Based on the damage variable defined by the ultrasonic wave velocity, the evolution equation of soil-cement accumulated fatigue damage is established. The equation indicates that the fatigue damage of soil-cement l under dynamic loading can obviously be divided into three stages: the initial rapid decay of the initial state, stability decay and rapid damage close to the destruction. The experiment results provide an important reference for non-destructive testing of soil-cement under dynamic loading.

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A Novel Method for High Temperature Fatigue Testing of Nickel Superalloy Turbine Blades with Additional NDT Diagnostics

Materials ◽

10.3390/ma14061392 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1392

Author(s):

Dominik Kukla ◽

Mateusz Kopec ◽

Ryszard Sitek ◽

Aleksander Olejnik ◽

Stanisław Kachel ◽

...

Keyword(s):

Finite Element ◽

High Temperature ◽

Fatigue Testing ◽

Turbine Blades ◽

Nickel Superalloy ◽

Fe Model ◽

Destructive Testing ◽

High Temperature Fatigue ◽

Bending Load ◽

Novel Method

In this paper, a novel method for high temperature fatigue strength assessment of nickel superalloy turbine blades after operation at different times (303 and 473 h) was presented. The studies included destructive testing (fatigue testing at temperature 950 °C under cyclic bending load), non-destructive testing (Fluorescent Penetrant Inspection and Eddy Current method), and finite element modelling. High temperature fatigue tests were performed within load range from 5200 to 6600 N using a special self-designed blade grip attached to the conventional testing machine. The experimental results were compared with the finite element model generated from the ANSYS software. It was found that failure of turbine blades occurred in the area with the highest stress concertation, which was accurately predicted by the finite element (FE) model.

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EFFECT OF FATIGUE TEST ON SPOT WELDED STRUCTURAL JOINT

Jurnal Teknologi ◽

10.11113/jt.v79.11290 ◽

2017 ◽

Vol 79 (5-2) ◽

Author(s):

Mohammad Khalid Wahid ◽

Muhammad Nabil Muhammed Sufian ◽

Mohamed Saiful Firdaus Hussin

Keyword(s):

Life Cycle ◽

Fatigue Life ◽

Fatigue Strength ◽

Spot Welding ◽

Fatigue Testing ◽

Fatigue Stress ◽

Component Design ◽

Welded Structure ◽

Different Thickness ◽

Spot Welded

Spot welding is mainly used method in joining sheet metals for body structure in automotive industry. The comprehension of the fatigue strength for the spot welds is very critical in automotive component design. Parameter for the resistance spot welding and fatigue machines is constant for each specimen used. The S-N curve is obtained from the fatigue testing for each specimen. This experiment parameters are varies the different thickness and different material combination in spot welding structure to investigate the fatigue life cycle and fatigue stress. For 1050A aluminium joint, fatigue life cycle and fatigue strength will decrease from number of cycle 500 at 16.58 MPa to number of cycle 61 at 6.62 MPa as the thickness increase. The fatigue life cycle and fatigue stress for galvanized iron will increase from number of cycle 46 at 9.25 MPa to number of cycle 1500 at 57.8 MPa when the thickness of joint increase. The finding from the combination of 1050A aluminum and galvanized iron on spot welded structure has shown no improvement in term of fatigue life cycle and fatigue strength because specimens experienced failure at number of cycle 19 with fatigue stress 2.36 MPa.

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