Strain Rate Sensitivity and Crash Modeling of High Strength Steels

Material Data
Material Models
Crash Tests
Project Description

Circular Tube Crush Tests, TMAC [+]
Dynamic axial compression tests have been conducted on circular tube specimens using the intermediate strain rate servo-hydraulic test machine. These tests are conducted on different AISI material grades: DQSK (1.6mm), HSLA340 (1.6 mm), DP590 (1.6 mm), DP780 (1.2 mm), BH300 (1.6 mm), TRIP600 (1.6 mm), TRIP780 (1.6 mm), 440WGA (1.2 mm) and DP780 HDGI Steel (1.2 mm). For each of these materials, nine tests were run, corresponding to three replicates at three different test velocities. In each case, minimum two out of the three replicates were instrumented with a maximum of sixteen strain gages in locations of crush fold formation. The inner diameter (100 mm) and the height (180 mm) of all the tubes were the same for all material grades to allow for comparison and common tube fixturing. [+]

Octagonal Tube Crush Tests, TMAC [+]
Octgonal tube html. [-]

Spotweld Tests, Drop Tower [+]
Static and dynamic strength tests were performed for spot welded specimens made of dual-phase (DP780) and mild steels (DQSK). Steels were provided by A/SP members and welds were made by RoMan Engineering. Lap-shear (LP) and cross-tension (CT) as well as a newly designed mixed mode specimens were tested using MTS hydraulic universal testing machine for static and drop weight tower for dynamic tests. Three weld nugget sizes for each steel and specimen geometry (LP and CT) were made. In the mixed mode test, only DP780 of one weld size was tested. Load and displacement as functions of time and failure mode of the spot welds were recorded in the tests. [+]

Base Material Tests, High Speed Hydraulics [+]
In support of the Auto/Steel Partnership (A/S-P), Strain Rate Characterization Project, ORNL will conduct high rate experimental tensile tests and analysis of base materials. The objective of the test program is to provide the necessary experimental data in support of the A/S-P efforts to determine high-strain-rate mechanical properties of Advanced High Strength Steels (AHSS). The experiments and data will also enable better predictive modeling of base materials for finite element crash modeling. The test program will consist of testing tensile specimens under strain rates of quasi-static, 0.1/s, 1/s, 10/s, 100/s, and maximum strain rates achievable in full open loop configuration. The tests will be conducted on the new hydraulic test equipment at the Oak Ridge National Laboratory. All the tests will be conducted using the same apparatus. If an effective gage length for the chosen specimen is known the equipment can be programmed to run non-linear velocities in the drive file to achieve global strain control (engineering or true strain rate as desired). High-speed video recording provide detailed record of the test as well as displacement data for strain measurements. [+]

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