Dynamic crushing of 2D cellular structures: Local strain field and shock wave velocity

Liao, Shasha; Zheng, Zizhan; Yu, Jilin

doi:10.1016/j.ijimpeng.2013.01.008

Cited by 45 publications

(37 citation statements)

References 25 publications

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“…The cellular nature of the materials allowed for only discrete displacement field of nodes, which prevented direct calculation of the deformation gradient, thus a discrete local deformation gradient based on the least square error defined in Refs. (Li and Shimizu, 2002;Gullett et al, 2008;Zimmerman et al, 2009;Liao et al, 2013) was employed.…”

Section: Local Strain Mappingmentioning

confidence: 99%

Dynamic crushing of uniform and density graded cellular structures based on the circle arc model

Zhang

Wei

Wang

et al. 2015

Lat. Am. j. solids struct.

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A new circle-arc model was established to present the cellular structure. Dynamic response of models with density gradients under constant velocities is investigated by employing Ls-dyna 971. Compared with the uniform models, the quasi-static plateau stress of different layers seems a significant parameter correlated with the deformation mode except for inertia effect when the density gradient is introduced. The impact velocity becomes much more vital on the deformation of the unit cell than the density gradient. The stress at both the impact and stationary sides is investigated in details. Furthermore, the stress-strain curve is compared with the modified shock wave theory. The density gradient does have some remarkable influence on the energy absorption capability, and a certain density gradient is not always beneficial to the energy absorption. Irrespective of the impact velocity, there seems always a critical strain where the energy absorbed by all these specimens could approximate to nearly the same value. So the critical strain-velocity curve is plotted and gives the beneficial area for energy absorption pertinent to density gradients and impact velocity.

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Section: Local Strain Mappingmentioning

confidence: 99%

Dynamic crushing of uniform and density graded cellular structures based on the circle arc model

Zhang

Wei

Wang

et al. 2015

Lat. Am. j. solids struct.

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“…A method based on the optimal local deformation gradient was proposed by Liao et al (2013) to calculate the local strain field of Voronoi honeycombs. The propagation of shock wave was found to be obviously one-dimensional no matter under the Shock Mode or the Transitional Mode.…”

Section: Latin American Journal Of Solids and Structures 14 (2017) 12mentioning

confidence: 99%

“…Information, such as the stress and strain of every element, can be obtained from the ABAQUS output files but it cannot be used to represent the local stress/strain at the continuum level. Based on the optimal local deformation gradient technique, a local strain field calculation method for cellular materials has been developed by Liao et al (2013Liao et al ( , 2014 to calculate the local strain. However, the local stress cannot be calculated in a similar manner and the mission of calculating the local stress field for cellular materials seems to be impossible.…”

Section: Calculation Of One-dimensional Cross-sectional Stressmentioning

confidence: 99%

“…However, the local stress cannot be calculated in a similar manner and the mission of calculating the local stress field for cellular materials seems to be impossible. Fortunately, it was observed that the propagation of shock wave is in a nearly one-dimensional form when cellular materials are crushed under high-velocity impact (Reid and Peng, 1997;Ruan et al, 2003;Tan et al, 2005a;Zou et al, 2009;Liao et al, 2013) and the one-dimensional approximation is popularly used. Thus, we can focus on the one-dimensional stress distribution and use the force on the cross section of cellular material to calculate the cross-sectional stress.…”

Section: Calculation Of One-dimensional Cross-sectional Stressmentioning

confidence: 99%

“…For simplicity, the shock wave speed is directly calculated from the R-PP-L shock model (Reid and Peng, 1997;Liao et al, 2013), i.e. Vs = V/ε L , where ε L is the locking strain, which is defined as the strain when the maximum value of the energy absorption efficiency function reaches (Tan et al, 2002;Tan et al, 2005).…”

Section: Relation Between Cross-sectional Stress and Impact Timementioning

confidence: 99%

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Stress Distribution in Graded Cellular Materials Under Dynamic Compression

Wang

Zheng

et al. 2017

Lat. Am. j. solids struct.

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Dynamic compression behaviors of density-homogeneous and density-graded irregular honeycombs are investigated using cell-based finite element models under a constant-velocity impact scenario. A method based on the cross-sectional engineering stress is developed to obtain the one-dimensional stress distribution along the loading direction in a cellular specimen. The cross-sectional engineering stress is contributed by two parts: the node-transitive stress and the contact-induced stress, which are caused by the nodal force and the contact of cell walls, respectively. It is found that the contactinduced stress is dominant for the significantly enhanced stress behind the shock front. The stress enhancement and the compaction wave propagation can be observed through the stress distributions in honeycombs under high-velocity compression. The single and double compaction wave modes are observed directly from the stress distributions. Theoretical analysis of the compaction wave propagation in the density-graded honeycombs based on the R-PH (rigid-plastic hardening) idealization is carried out and verified by the numerical simulations. It is found that stress distribution in cellular materials and the compaction wave propagation characteristics under dynamic compression can be approximately predicted by the R-PH shock model. dynamic crushing. However, most research work is restricted to the stress at the impact/support end and thus the stress distribution is not well considered. KeywordsSignificant enhancement of crushing stress was observed in the dynamic impact experiments of woods (Reid and Peng, 1997;Harrigan et al., 2005), aluminum honeycombs (Zhao and Gary, 1998;Hou et al., 2012) and foams (Mukai et al., 1999;Deshpand and Fleck, 2000;Tan et al., 2005a;Elnasri et al., 2007). Several shock models and mass-spring models have been proposed to understand the shock wave propagation in cellular materials under dynamic impact, such as the R-PP-L (rate-independent, rigid-perfectly plastic-locking) model (Reid and Peng, 1997), the mass-spring model (Li and Meng, 2002), the E-PP-R (elastic-perfectly plastic-rigid) model (Lopatnikov et al., 2003), the power law densification model and the D-R-PH (dynamic, rigidplastic hardening) shock model . Because the assurance of the repeatability of samples and the measurement of local stress and strain states have not been well solved by experimental techniques, finite element (FE) method has been applied to simulate the dynamic crushing of cellular materials, such as regular/irregular honeycombs (Ruan et al., 2003;Zheng et al., 2005;Liu et al., 2009;Zou et al., 2009;Hu and Yu, 2013) and open-/closed-cell foams Zheng et al., 2014;Sun et al., 2016). The typical features of stress enhancement and deformation localization can be appropriately represented.The introduction of gradient to cellular structures may influence the macroscopic mechanical properties, and thus graded cellular materials have become popular in energy absorption and impact resistance. The compressive mechanical ...

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