A Constitutive Model for Metals at High Strain Rates Accurately Determined by the Tensile Impact Recovery Experimental Technique

1997 ◽  
Vol 25 (4) ◽  
pp. 378
Author(s):  
DR Petersen ◽  
C Wang ◽  
Y Zhou ◽  
Y Xia
Keyword(s):  
Constitutive Model ◽  
Experimental Technique ◽  
High Strain ◽  
Strain Rates ◽  
High Strain Rates ◽  
Tensile Impact

scholarly journals Formulation of Orthotropic Constitutive Model for Concrete Materials under High Strain-Rates and Triaxial Stress States.

2001 ◽  
pp. 109-123 ◽  
Author(s):  
Kazunori FUJIKAKE ◽  
Katsutoshi UEBAYASHI ◽  
Tomonori OHNO ◽  
Jun MIZUNO ◽  
Atsushi SUZUKI
Keyword(s):  
Constitutive Model ◽  
High Strain ◽  
Triaxial Stress ◽  
Strain Rates ◽  
High Strain Rates ◽  
Concrete Materials ◽  
Stress States

Constitutive Behavior of SAC Leadfree Alloys at High Strain Rates

2011 ◽  
Author(s):  
Pradeep Lall ◽  
Sandeep Shantaram ◽  
Mandar Kulkarni ◽  
Geeta Limaye ◽  
Jeff Suhling
Keyword(s):  
Constitutive Model ◽  
Solder Alloy ◽  
Failure Modes ◽  
High Strain ◽  
Image Correlation ◽  
Constitutive Behavior ◽  
Strain Rates ◽  
Mechanical Shock ◽  
High Strain Rates ◽  
Test Technique

Electronic products are subjected to high G-levels during mechanical shock and vibration. Failure-modes include solder-joint failures, pad cratering, chip-cracking, copper trace fracture, and underfill fillet failures. The second-level interconnects may be experience high-strain rates and accrue damage during repetitive exposure to mechanical shock. Industry migration to leadfree solders has resulted in proliferation of a wide variety of solder alloy compositions. Few of the popular tin-silver-copper alloys include Sn1Ag0.5Cu and Sn3Ag0.5Cu. The high strain rate properties of leadfree solder alloys are scarce. Typical material tests systems are not well suited for measurement of high strain rates typical of mechanical shock. Previously, high strain rates techniques such as the Split Hopkinson Pressure Bar (SHPB) can be used for strain rates of 1000 per sec. However, measurement of materials at strain rates of 1–100 per sec which are typical of mechanical shock is difficult to address. In this paper, a new test-technique developed by the authors has been presented for measurement of material constitutive behavior. The instrument enables attaining strain rates in the neighborhood of 1 to 100 per sec. High speed cameras operating at 300,000 fps have been used in conjunction with digital image correlation for the measurement of full-field strain during the test. Constancy of cross-head velocity has been demonstrated during the test from the unloaded state to the specimen failure. Solder alloy constitutive behavior has been measured for SAC105, and SAC305 solders. Constitutive model has been fit to the material data. Samples have been tested at various time under thermal aging at 25°C and 125°C. The constitutive model has been embedded into an explicit finite element framework for the purpose of life-prediction of leadfree interconnects. Test assemblies has been fabricated and tested under JEDEC JESD22-B111 specified condition for mechanical shock. Model predictions have been correlated with experimental data.

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