Measuring the Mechanical Properties of Aluminum Sheets and Their Resistance Spot Welds at Large Strains Using Digital Image Correlation Coupled with a Modified Shear Test

2012 ◽  
Author(s):  
Jidong Kang ◽  
Joseph McDermid ◽  
Moise Bruhis
Keyword(s):  
Mechanical Properties ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Shear Test ◽  
Image Correlation ◽  
Large Strains ◽  
Spot Welds ◽  
Resistance Spot ◽  
Aluminum Sheets ◽  
Resistance Spot Welds

Identification of the Mechanical Properties of High-Strength Steel Using Digital Image Correlation

2014 ◽  
Vol 980 ◽  
pp. 122-126 ◽  
Author(s):  
Michaela Štamborská ◽  
Miroslav Kvíčala ◽  
Monika Losertová
Keyword(s):  
Mechanical Properties ◽  
Digital Image Correlation ◽  
Digital Image ◽  
High Strength Steel ◽  
Strain Field ◽  
High Strength ◽  
Image Correlation ◽  
Uniaxial Tensile ◽  
Large Strains ◽  
Identification Procedure

Identification of the mechanical properties of high-strength steel using digital image correlation. In this paper an experimental procedure to identify the plastic behaviour of sheet metals up to large strains using full field measurement is presented. The tests were conducted on notched specimens. This geometry generates a heterogeneous strain field which was measured during the test using a digital image correlation system. The advantage of using a heterogeneous strain field in the identification procedure is that a complex state of stress-strain can be analyzed at the same time and much more information can be obtained in a single test. On the other hand, the stress field cannot be directly computed from the test and a suitable identification procedure must be developed. Here, the virtual fields method (VFM) adapted for large strains and plasticity was used to identify the hardening behaviour and the anisotropy of the material. The values obtained with the VFM were compared with the results from a standard identification made using uniaxial tensile tests.

scholarly journals Effect of weld nugget size on failure mode and mechanical properties of microscale resistance spot welds on Ti–1Al–1Mn ultrathin foils

2018 ◽  
Vol 10 (7) ◽  
pp. 168781401878528 ◽  
Author(s):  
Feng Chen ◽  
Shiding Sun ◽  
Zhenwu Ma ◽  
GQ Tong ◽  
Xiang Huang
Keyword(s):  
Mechanical Properties ◽  
Failure Mode ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Weld Nugget ◽  
Interfacial Failure ◽  
Spot Welds ◽  
Resistance Spot ◽  
Resistance Spot Welds ◽  
Pullout Failure

We use tensile–shear tests to investigate the failure modes of Ti–1Al–1Mn microscale resistance spot welds and to determine how the failure mode affects the microstructure, microhardness profile, and mechanical performance. Two different failure modes were revealed: interfacial failure mode and pullout failure mode. The welds that fail by pullout failure mode have much better mechanical properties than those that fail by interfacial failure mode. The results show that weld nugget size is also a principal factor that determines the failure mode of microscale resistance spot welds. A minimum weld nugget size exists above which all specimens fail by pullout failure mode. However, the critical weld nugget sizes calculated using the existing recommendations are not consistent with the present experimental results. We propose instead a modified model based on distortion energy theory to ensure pullout failure. Calculating the critical weld nugget size using this model provides results that are consistent with the experimental data to high accuracy.

scholarly journals Measurement of mechanical properties of carp scales based on digital image correlation method

2020 ◽  
Vol 1605 ◽  
pp. 012107
Author(s):  
Zhongnan Fu ◽  
Wanlong Ma ◽  
Tiantian Zhu ◽  
Pei Ye ◽  
Guihua Li
Keyword(s):  
Mechanical Properties ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Correlation Method ◽  
Image Correlation ◽  
Digital Image Correlation Method

Local Elasto-Plastic Identification of the Behaviour of Friction Stir Welds with the Virtual Fields Method

2011 ◽  
Vol 70 ◽  
pp. 135-140 ◽  
Author(s):  
G. Le Louëdec ◽  
M.A. Sutton ◽  
Fabrice Pierron
Keyword(s):  
Mechanical Properties ◽  
Digital Image Correlation ◽  
Digital Image ◽  
High Speed ◽  
Weld Zone ◽  
Spatial Variations ◽  
Image Correlation ◽  
Virtual Fields Method ◽  
Full Field ◽  
Friction Stir

Welding is one of the most popular joining technologies in industry. Depending on the materials to be joined, the geometry of the parts and the number of parts to be joined, there is a wide variety of methods that can be used. These joining techniques share a common feature: the material in the weld zone experiences different thermo-mechanical history, resulting in significant variations in material microstructure and spatial heterogeneity in mechanical properties. To optimize the joining process, or to refine the design of welded structures, it is necessary to identify the local mechanical properties within the different regions of the weld. The development of full-field kinematic measurements (digital image correlation, speckle interferometry, etc.) helps to shed a new light on this problem. The large amount of experimental information attained with these methods makes it possible to visualize the spatial distribution of strain on the specimen surface. Full-field kinematic measurements provide more information regarding the spatial variations in material behaviour. As a consequence, it is now possible to quantify the spatial variations in mechanical properties within the weld region through a properly constructed inverse analysis procedure. High speed tensile tests have been performed on FSW aluminium welds. The test was performed on an MTS machine at a cross-head speed of up to 76 mm/s. Displacement fields were measured across the specimen by coupling digital image correlation with a high-speed camera (Phantom V7.1) taking 1000 frames per second. Then, through the use of the virtual fields method it is possible to retrieve the mechanical parameters of the different areas of the weld from the strain field and the loading. The elastic parameters (Young’s modulus and Poisson’s ratio) are supposed to be constant through the weld. Their identification was carried out using the virtual fields method in elasticity using the data of the early stage of the experiment. Assuming that the mechanical properties (elastic and plastic) of the weld are constant through the thickness, the plastic parameters were identified on small sections through the specimen, using a simple linear hardening model. This method leads to a discrete identification of the evolution of the mechanical properties through the weld. It allows the understanding of the slight variations of yield stress and hardening due to the complexity of the welding process.

Factors affecting mechanical properties of resistance spot welds

2010 ◽  
Vol 26 (9) ◽  
pp. 1137-1144 ◽  
Author(s):  
M. Pouranvari ◽  
S. P. H. Marashi
Keyword(s):  
Mechanical Properties ◽  
Spot Welds ◽  
Factors Affecting ◽  
Resistance Spot ◽  
Resistance Spot Welds
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