Axial crush simulation of braided carbon tubes using MAT58 in LS-DYNA

Xiao, Xinran; Botkin, Mark E.; Johnson, Nancy L.

doi:10.1016/j.tws.2008.12.004

Cited by 100 publications

(38 citation statements)

References 21 publications

(27 reference statements)

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“…This material model is capable of predicting initiation and evolution of intralaminar damage through degrading elastic moduli [35]. It is suitable for modelling UD and woven composites.…”

Section: Fe Model Of the Helmetmentioning

confidence: 99%

Influence of the body on the response of the helmeted head during impact

Ghajari

Galvanetto

Iannucci

et al. 2011

International Journal of Crashworthiness

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The most frequent type of injury that causes death or disability in motorcycle accidents is head injury. The only item of personal protective equipment that protects a motorcyclist's head in real-world accidents is the safety helmet. The protective capability of a helmet is assessed, according to international standards, through the impact of a headform fitted with the helmet onto an anvil. The purpose of the present work was to study the influence of the presence of the body on the impact response of the helmeted head. Full-body and detached-head impacts were simulated using the finite element (FE) method. As a consequence of the presence of the body, the crushing distance of the helmet liner was drastically increased. This evidence indicated that the effect of the body should be included in impact absorption tests in order to provide conditions that are more realistic and stringent. The solution to an analytical model of the helmeted headform impact revealed that increasing the headform mass has the same influence on impact outputs, particularly the liner's crushing distance, as including the whole body in impact tests. The added mass was calculated by using a helmeted Hybrid III dummy for an impact configuration that frequently occurred in real-world accidents

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“…This material model is capable of predicting initiation and evolution of intralaminar damage through degrading elastic moduli [35]. It is suitable for modelling UD and woven composites.…”

Section: Fe Model Of the Helmetmentioning

confidence: 99%

Influence of the body on the response of the helmeted head during impact

Ghajari

Galvanetto

Iannucci

et al. 2011

International Journal of Crashworthiness

View full text Add to dashboard Cite

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“…The CDM has been widely used for the damage analysis of composite structures in the past 20 years . Based on the thermodynamics theory, the CDM introduces damage variables as internal variables, which are defined as the ratio between damage area and undamaged area – …”

Section: Numerical Model Of Low‐velocity Impactmentioning

confidence: 99%

A new numerical model for the analysis on low‐velocity impact damage evolution of carbon fiber reinforced resin composites

Sun

Ping

et al. 2016

J of Applied Polymer Sci

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A new numerical simulation method was proposed to predict the mechanical behavior of carbon fiber reinforced resin composites under low‐velocity impact load. The impact damage evolution can be characterized in the form of energy dissipation which can be calculated through the new numerical model. The evolution mechanism of delamination was analyzed through distinguishing between the normal induced delamination and tangential slip induced delamination. The drop weight tests were conducted on composite laminates with five kinds of stacking sequence. Experimental analysis was also presented in this article. The damage area and distribution was investigated through ultrasonic C‐scan. The prediction had a good agreement with the experimental results through the comparison of impact response. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44374.

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“…Table 2 and Figure 3 show different types of lamina used in the shell and the layups in different regions of the shell, respectively. In the FE model, Laminated Composite Fabric material model (MAT_058 from LS-Dyna material library) was used for the shell [43,45] with the material constants presented in Table 3. MAT_058 has the capability of predicting the failure initiation and evolution in composite plies according to the following constitutive equation [48,49]:…”

Section: Helmet Fe Modelmentioning

confidence: 99%

“…The subscripts L and T indicate longitudinal and transverse directions. is the damage function which is defined as follows [49]:…”

Section: Helmet Fe Modelmentioning

confidence: 99%

“…where isthe ratio of the limiting stress to the peak stress [49,50] and has been considered equal to 0.1 [43,44]for the present study. In this material model when an element fails, its moduli degrade to near zero but the element will not be deleted in order to avoid instability problems at the interfaces with other parts, like liner and anvil in the present work [44,45].…”

Section: Helmet Fe Modelmentioning

confidence: 99%

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Optimization of the Chin Bar of a Composite-Shell Helmet to Mitigate the Upper Neck Force

2016

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The chin bar of motorcycle full-face helmets is the most likely region of the helmet to sustain impacts during accidents, with a large percentage of these impacts leading to basilar skull fracture. Currently, helmet chin bars are designed to mitigate the peak acceleration at the centre of gravity of isolated headforms, as required by standards, but they are not designed to mitigate the neck force, which is probably the cause of basilar skull fracture, a type of head injury that can lead to fatalities. Here we test whether it is possible to increase the protection of helmet chin bars while meeting standard requirements. Fibre-reinforced composite shells are commonly used in helmets due to their lightweight and energy absorption characteristics. We optimize the ply orientation of a chin bar made of fibre-reinforced composite layers for reduction of the neck force in a dummy model using a computational approach. We use the finite element model of a human head/neck surrogate and measure the neck axial force, which has been shown to be correlated with the risk of basilar skull fracture. The results show that by varying the orientation of the chin bar plies, thus keeping the helmet mass constant, the neck axial force can be reduced by approximately 30% while ensuring that the helmet complies with the impact attenuation requirements prescribed in helmet standards. KeywordsHelmet, chin bar, upper neck force.

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Axial crush simulation of braided carbon tubes using MAT58 in LS-DYNA

Cited by 100 publications

References 21 publications

Influence of the body on the response of the helmeted head during impact

Influence of the body on the response of the helmeted head during impact

A new numerical model for the analysis on low‐velocity impact damage evolution of carbon fiber reinforced resin composites

Optimization of the Chin Bar of a Composite-Shell Helmet to Mitigate the Upper Neck Force

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