scholarly journals Assessment of Material Dislocation Damage by Nonlinear Ultrasound

2020 ◽  
Vol 316 ◽  
pp. 01001
Author(s):  
Zaifu Zhan ◽  
Shen Wang ◽  
Songling Huang ◽  
Yang Zheng ◽  
Fuping Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ultrasonic Wave ◽  
Ultrasonic Testing ◽  
Harsh Environment ◽  
Nonlinear Phenomenon ◽  
Constitutive Behaviour ◽  
Nonlinear Detection ◽  
Nonlinear Ultrasonic ◽  
Properties Of Materials ◽  
Harmonic Components

Under harsh environment or during service, the mechanical properties of materials or structure will deteriorate. Most of the simulations exhibit the phenomenon of nonlinearity by introducing the actual small defects, without considering dislocation. In this manuscript, subroutines are written to change the mechanical constitutive behaviour of materials. When the mechanical constitutive behaviour of the material is not linear any more, it is found that the propagation of ultrasonic wave in the material will show more obvious nonlinear phenomenon. Furthermore, the nonlinear detection coefficient is used to characterize the increase of harmonic components. This work provides a new idea for nonlinear ultrasonic testing.

Effect of SiC Defects on Performance of Particle Reinforced Aluminum Matrix Composites

2020 ◽  
Vol 993 ◽  
pp. 730-738
Author(s):  
Zhong Run Xiao ◽  
Jun Hui Nie ◽  
Jian Zhong Fan
Keyword(s):  
Mechanical Properties ◽  
Ultrasonic Testing ◽  
Aluminum Matrix ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Large Area ◽  
The Matrix ◽  
Sic Particulates ◽  
Properties Of Materials ◽  
The Difference

The effect of segregation defect of SiC particles on the properties of materials was studied. 15% SiCp/2009Al composites were prepared by powder metallurgy (PM). Special SiC/Al samples were added to 15% SiCp/2009Al composites. These SiC/Al samples with different sizes and volume fractions were 25%, 35%, 45% and 60%, respectively, which resulted in SiC particulates segregation defect. The 15% SiCp/2009Al composites with defects were tested by ultrasonic testing. Tensile samples were obtained at the locations, where defects might be detected and the mechanical properties were tested. The results showed that all defective samples were cracked at the defective location. The difference in tensile strength between the samples of defect and the samples without defect was large. The toughness of the sample containing the defect reduced and the brittleness increased. The dimples on the matrix indicate that ductile fracture occurred during the fracture process. The cleavage fracture or cracking of the SiC particulates indicated that the stress can be effectively transferred from the matrix to the particles, and the particulates strengthen the matrix well. However, the sample with defect led to brittle fracture in the defect, and a crack source produced at the interface, resulting in a significant decrease in the mechanical properties of the material. If the inhomogeneous distribution of particulate containing a large area was found in the ultrasonic testing of the aluminum matrix composites, the tensile properties of the products generally cannot meet the requirement for application.

scholarly journals Mechanical properties evaluation and ultrasound diagnosis of unsaturated polyester-glass pipes

2015 ◽  
Vol 17 (2) ◽  
pp. 77-83 ◽  
Author(s):  
Gabriel Wróbel ◽  
Maciej Rojek ◽  
Małgorzata Szymiczek
Keyword(s):  
Mechanical Properties ◽  
Ultrasonic Wave ◽  
Ultrasonic Testing ◽  
Unsaturated Polyester ◽  
Glass Fibers ◽  
Degradation Process ◽  
Transition Time ◽  
Simulation Tool ◽  
Material Condition ◽  
Poly Vinyl Chloride

Abstract The purpose of the present work was the elaboration of research methodology of the exhaustion degree of performance properties of pipes based on unsaturated polyester and glass fibers, which were manufactured by the cross winding method on a poly(vinyl chloride) core. Within the frame of the work we conducted fatigue-ageing tests being the simulation tool of the degradation process of polyester-glass pipes. Diagnosis of the composite material condition was conducted with the use of nondestructive ultrasonic testing with the application of the echo method, in which the transition time of ultrasonic wave was determined as the identifying parameter. The registered transition time of ultrasonic wave allowed the identification of the material condition during the course of pipes exploitation.

LABORATORY TESTS OF THE PHYSICAL-MECHANICAL PROPERTIES OF MATERIALS FOR REMEDIAL JOBS

2020 ◽  
pp. 58-63
Author(s):  
M.A. Druzhinin ◽  
◽  
G.V. Okromelidze ◽  
O.V. Garshina ◽  
I.A. Kudimov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Laboratory Tests ◽  
Mechanical Properties Of Materials ◽  
Properties Of Materials

Optimizing the Shape and Size of Cruciform Specimens Used for Biaxial Tensile Test

2014 ◽  
Vol 658 ◽  
pp. 167-172 ◽  
Author(s):  
Liviu Andrusca ◽  
Viorel Goanta ◽  
Paul Doru Barsanescu
Keyword(s):  
Mechanical Properties ◽  
Tensile Test ◽  
Continuous Monitoring ◽  
Biaxial Tension ◽  
Cruciform Specimen ◽  
Testing Method ◽  
Biaxial Tests ◽  
Properties Of Materials ◽  
Failure Theories ◽  
Shape And Size

Testing cruciform specimens subjected to biaxial tension is one of the most widely used experimental techniques and more accurate at this time to determine the mechanical properties of materials and to verify the failure theories. This type of experiment allows the continuous monitoring of behavior of materials from the beginning of deformation until fracture under different ratios of forces and directions of the deformation, which transforms it into a very versatile testing method. We have varied the number of parameters and their values in order to achieve a uniform distribution of biaxial state of stresses and strains in the area tested. In theory, any material can be tested by stretching a biaxial cruciform specimen, but must be investigated in what way the shape of the specimen influence the data obtained. In this paper are presented the requirements that must be fulfilled by the samples used for tensile / compression biaxial tests and the design of cruciform specimens through FEA that meet these demands.

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