Effect of strain rate on dynamic responses of laterally impacted steel plates

2019 ◽  
Vol 160 ◽  
pp. 307-317 ◽  
Author(s):  
Bin Liu ◽  
C. Guedes Soares
Keyword(s):  
Strain Rate ◽  
Steel Plates ◽  
Dynamic Responses

A Dislocation Dynamics Based Constitutive Model and Experimental Validations by 3D Microscale Laser Dynamic Forming of Metallic Thin Films

2010 ◽  
Author(s):  
Huang Gao ◽  
Gary J. Cheng
Keyword(s):  
Constitutive Model ◽  
Strain Rate ◽  
Cell Size ◽  
High Speed ◽  
Dislocation Dynamics ◽  
Dynamic Responses ◽  
Strength Increase ◽  
Strain Rate Effects ◽  
Discrete Dislocation ◽  
Thickness Variations

Microscale Laser Dynamic Forming (μLDF) shows great potential in fabricating the robust and high-aspect-ratio metallic microcomponents by the high speed plasma shockwave. Experiments revealed that strain rate and sample size play important roles in determining the final results of μLDF. To further understand the deformation behavior, we develop a constitutive model integrating size effects and ultrahigh strain rate effects to predict the ultimate plastic deformations. To derive this model, 3-D Discrete Dislocation Dynamics (DDD) simulations are first set up to investigate the dislocation evolutions and the dynamic responses during shockwave propagation. It is observed that there exist three dynamic stages during deformation process, and the initial strain hardening rate in Stage II increases with strain rate. The simulation also reveals that stain softening occurs only for the smaller cell size due to two competing mechanisms. In addition, the simulation predicts that the flow stress and yield strength increase with the strain rate and decrease with cell size. The modified mechanical threshold stress (MTS) model integrating these effects is implemented in Abaqus/Explicit and predicts the deformation depth and thickness variations in good agreement with the experimental results.

scholarly journals Energy-Dissipation Performance of Combined Low Yield Point Steel Plate Damper Based on Topology Optimization and Its Application in Structural Control

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Haoxiang He ◽  
Xiaobing Wang ◽  
Xiaofu Zhang
Keyword(s):  
Topology Optimization ◽  
Energy Dissipation ◽  
Yield Stress ◽  
Yield Point ◽  
Structural Control ◽  
Steel Plate ◽  
Steel Plates ◽  
Dynamic Responses ◽  
Initial Stiffness ◽  
Seismic Capacity

In view of the disadvantages such as higher yield stress and inadequate adjustability, a combined low yield point steel plate damper involving low yield point steel plates and common steel plates is proposed. Three types of combined plate dampers with new hollow shapes are proposed, and the specific forms include interior hollow, boundary hollow, and ellipse hollow. The “maximum stiffness” and “full stress state” are used as the optimization objectives, and the topology optimization of different hollow forms by alternating optimization method is to obtain the optimal shape. Various combined steel plate dampers are calculated by finite element simulation, the results indicate that the initial stiffness of the boundary optimized damper and interior optimized damper is lager, the hysteresis curves are full, and there is no stress concentration. These two types of optimization models made in different materials rations are studied by numerical simulation, and the adjustability of yield stress of these combined dampers is verified. The nonlinear dynamic responses, seismic capacity, and damping effect of steel frame structures with different combined dampers are analyzed. The results show that the boundary optimized damper has better energy-dissipation capacity and is suitable for engineering application.

Static and Dynamic Low-Temperature KIc Behavior of Steels

1969 ◽  
Vol 91 (3) ◽  
pp. 512-518 ◽  
Author(s):  
A. K. Shoemaker ◽  
S. T. Rolfe
Keyword(s):  
Yield Strength ◽  
Strain Rate ◽  
Dynamic Test ◽  
Rate Sensitivity ◽  
Initial Step ◽  
Steel Plates ◽  
Temperature Sensitive ◽  
Static Test ◽  
Temperature Range ◽  
Machine Steel

To determine the crack-toughness behavior of steels subjected to high strain rates, a study was undertaken to establish the effects of strain rate and temperature on the KIc-values of steels. As an initial step, a procedure was developed to obtain dynamic KIc-values of steels by impact loading a fatigue-cracked bend specimen in a drop-weight machine. Steel plates having widely different yield strengths (40, 140, and 250 ksi) were studied initially to establish testing techniques. The results indicate that the procedures and analysis developed were satisfactory for determining static and dynamic KIc-values. For the 250 ksi yield strength steel [18Ni(250) maraging] the KIc linearly increased with increased temperature over a 400 F temperature range with no significant effect of strain rate. The strain rate had no effect on the KIc-values of the 140 ksi yield strength steel [HY-130(T)] between −320 and −150 F. However, in the 1-in-thick specimens the increase in strain rate which occurred in the dynamic test increased the temperature range for which plane-strain crack extension occurred. The KIc behavior of the 40 ksi yield strength steel (ABS-C) showed a marked sensitivity to strain rate with the same crack toughness being measured dynamically at a temperature 190 F higher than for the static test. Correlations of ABS-C steel KIc-values with its yield strength and a rate parameter, T In A/ε demonstrated the equivalency between decreasing temperature and increasing strain rate as influencing the crack toughness. The agreement of an estimate of KId from the dynamic yield strength at the NDT with the measured dynamic KIc-value showed that the six orders of magnitude increase in strain rate for this dynamic test appears sufficient to give KIc-values within 10 percent of the crack-toughness value estimates for a running crack in rate and temperature-sensitive steels. In general, the results of this investigation showed that a dynamic KIc test has been developed which can be used to establish the strain-rate sensitivity of the crack toughness of steels as well as corresponding design information.

Numerical Simulation of One-Way Reinforced Concrete Slabs Subjected to Blast Loadings

2013 ◽  
Vol 671-674 ◽  
pp. 726-730
Author(s):  
Tian Hua Li ◽  
Jun Hai Zhao ◽  
Xiao Ming Dong
Keyword(s):  
Numerical Simulation ◽  
Reinforced Concrete ◽  
Numerical Model ◽  
Strain Rate ◽  
Strain Rate Effect ◽  
Rate Effect ◽  
Dynamic Responses ◽  
Reinforced Concrete Slabs ◽  
Rc Slabs ◽  
Blast Loadings

The damage and failure of reinforced concrete (RC) slabs under blast loadings may cause significant hazards for frame systems even progressive collapse of whole structures. The numerical simulation of one-way RC slabs using the finite element explicit code LS-DYNA to estimate the dynamic response and failure mode of one-way RC slabs .Blast loadings are imposed on the top surface of slabs using a blast model based on conwep algorithm. Concrete was modeled using a concrete damage constitutive model considering strain rate effect, and reinforcement was modeled using a elastoplastic material type with kinematic hardening and strain rate effect. The numerical model is introduced in details and adopted to simulate the dynamic responses of RC slabs in reference test. The numerical model can match well with the test data, and thus the proposed numerical model can be considered as a valuable tool in assessing the deformation or failure mechanism and predicting the dynamic responses of one-way RC slabs subjected to blast loadings.

Effects of temperature and strain rate on the dynamic responses of three polymer-bonded explosives

2011 ◽  
Vol 47 (2) ◽  
pp. 104-112 ◽  
Author(s):  
Junling Li ◽  
Fangyun Lu ◽  
Jingui Qin ◽  
Rong Chen ◽  
Pengduo Zhao ◽  
...  
Keyword(s):  
Strain Rate ◽  
Dynamic Responses ◽  
Polymer Bonded Explosives ◽  
Effects Of Temperature

Assessment of material strain rate effects on square steel plates under lateral dynamic impact loads

2017 ◽  
Vol 13 (2) ◽  
pp. 217-225 ◽  
Author(s):  
Kun Liu ◽  
Bin Liu ◽  
R. Villavicencio ◽  
Zili Wang ◽  
C. Guedes Soares
Keyword(s):  
Strain Rate ◽  
Steel Plates ◽  
Impact Loads ◽  
Dynamic Impact ◽  
Strain Rate Effects ◽  
Rate Effects
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