材料动态力学性能测试技术

Applications, Relevant Strainrate Range, and Test Methods
地质，地理；建筑物；长
振动；地震；交通工 具碰撞
冲击物理；空间技 术；宇宙科学
期工业负荷；
兵工和航空航天应
一般工业民生载荷
用；一些工业应用
Rate Dependency of Material Properties
a 0
a 0 0L
Taylor Formula for Flow Stress
LL a Y a 0 0
;
L0 L0
,
L0
a
a
0
V0
L
பைடு நூலகம்
a a
0
V0
1
2a 0 Y
a 0V02
ln
L L0
0
a a 0
V0
1
2a 0 Y
a 0V02
ln
L1 X L0
a L0 X a 0 L0 L1
Symmetric Taylor Impact: (Limestone rod f10x100, 391m/s)
Taylor Impact of Foam Aluminum
Plane Impact Test
Spalling Signal
Rate Dependency of Failure Stress
Flow Stress of AP at ~3500 1/s
Hall-Petch Relationship:
y 0
k d
Dynamic Strength of Solder at Different Temperature
y 0.02 (MPa) 180.58 0.30573T (K )
Times from the moment of impact: 0, 329, 336, 420 ms.
Split Hopkinson Pressure Bar: Recent Developments
✓ 1980 Miniaturised direct impact Hopkinson bar ✓ 1985 Large SHPB for testing structures and concrete ✓ 1991 One pulse loading SHPBs ✓ 1991–1993 Torsional SHPB: sliding friction/shearing of lubricants ✓ 1992–2003 Development of polymer SHPB for testing foams ✓ 1997–2002 Wave separation techniques: Extend the effective length ✓ 1998 Development of magnesium SHPB for soft materials ✓ 1998 Development of radiant methods for fast heating metallic specimens ✓ 1998–2002 Analysis of wave propagation in non-uniform viscoelastic rods ✓ 1999 Development of one pulse torsion SHPB ✓ 2003 Extension of Hopkinson bar capability to intermediate strain rates ✓ 2003 Application of speckle metrology to specimen deformation
Plastic flow stress of copper
Failure stress of limestone
Inertial stress for copper specimen f3.8mmx2.3mm
i
a2 16
h2 6
2
h2 6
a2 8
h 2a
Drop Weight Experiments
Experimental Techniques for High Rate Deformation and Shock Studies
Hopkinson bar; Taylor impact; Plate impact; Dropweight; Ballistic impact; Shockloading; High speed photography; etc
Grady and Kipp Model
Rate Dependency of Failure Stress
Grady and Kipp Model
Zhou et al, Fragmentation Model
Taylor Impact Test & Analysis
L0
0
V0 L
0
C a
V X
0
a
L1
Analysis
Lt V t Ct
L dLt a Ct
dt
0
Lt
L0
t
0
V
C
d
V C a C , V a 0 C
0
0
L(t)
0LV Y
C(t) V(t)
L V C a V a Y
Testing Area
Stress Curve
Drop Weight Testing and High Speed Photography
Fracture of a Polycarbonate under drop weight loading
Ignition under impact of a thermite composition
Dynamic Strength of Solder at Room Temperature
y 0.02 (MPa) 74.786 0.01368 (s1)
Deformation of a SHPB Specimen under Loading
Deformation of a Brazilian Specimen under SHPB Loading
Y
L0 X 0V02
2L0
L1 ln
L0 X
Modified Taylor Impact Analysis: Including Strain Hardening
L0
0
V0
L
0
C a
Y
V
X
0
a
L
1
• 王礼立，《应力波基础》，145-147
Symmetric Taylor Impact: (Copper rod f10x100, 395m/s)