Strain Measurement in Local Volume by Non-Contact Videoextensometric Technique on Ultra High Strength Steels

Abstract

The paper presents the results of strain measurement using two methods: videoextensometry (ME46) and digital image correlation (DIC)-ARAMIS. ME46 - allows measuring and monitoring the major and minor strain on a planar surface of a loaded object [1]. Experimental equipment uses a CCD camera for monitoring the process. The software calculates the displacements of contrast dots and subsequently the strain components are obtained. Another method for non-contact measurements is DIC technique; the measurements are done using three-dimensional image correlation system. The system uses two digital high-speed cameras providing a synchronized stereo view of the specimen where speckles are arranged on the surface. The results show the complete strain field during the tests, including details of the strain field when necking develops prior to the failure [2]. Experimental results obtained on ultra high strength automotive steels DP 1000 and 1400M grades during static tensile test are presented in the paper. The outputs of both are deformation maps. Advantages and disadvantages of both methods are compared.

Elimination of Shrinkage in Ductile Iron Castings Using Computer Simulation of Casting and Solidification

“…The danger of particle entrainment increases as the flow velocity increases to a value of approximately 1.2 m/s, at which point entrainment damage to the mold is likely. The flow velocity in the notches should be in the range of 0.5 to 1.0 m/s [3][4][5][6].…”

The Design and Production of a Suitable Carrier for Microwires Used for Non-Contact Detection of Mechanical Strains

“…Methods not yet used for systematic monitoring of load-bearing structures include one based on comparing digital images of a sample during its loading with a system of digital image correlation using a charge-coupled device (CCD) camera, and another based on determining the position of light-emitting diodes (LEDs) placed on the surface of the sample using a trio of CCD cameras (LED-CCD) [22] and video extensometry, which is used to monitor fracture processes in metallic materials [23].…”

EVALUATION OF FORMABILITY OF THIN SHEETS BASED ON Al-Mg-Si FOR AUTOMOTIVE INDUSTRY

“…Non-contact techniques allow monitoring whole testing proces and provide information about measured area. Often used non-contact techniques for strain measurement are videoextensometry, DIC (digital image correlation), ESPI (electronic speckle pattern interferometry), etc [20,21]. The DIC method is a optical method which is used to measure the relative spatial deformations and displacements.…”

“…Measuring systems which operate on the principle of DIC method have many advantages against conventional method. For example: without contact with the measured object, possibility of measuring in any position monitored area, the ability to capture non-homogeneous deformation field in all areas, the ability to direct measurement that requires numerical or analytical processing of results, application in places where it is impossible or very difficult, high accuracy displacements of individual contrast points in the monitored field [18][19][20][21][22]. In this paper are obtained mechanical properties, microstructure and hardness of aluminium alloy for three differently direction of rolling.…”