Showing papers by "Michael May published in 2015"
TL;DR: In this paper, a detailed experimental characterization of quasi-static anisotropic directional strength properties as well as the shock behavior of ultra-high molecular weight polyethylene (UHMWPE) for the development of an advanced material model for this class of materials is presented.
106 citations
TL;DR: In this article, the authors developed a fully rate-dependent constitutive law for cohesive interface elements considering both, the strain rate dependency of the initiation stress and the strain ratio dependency of fracture toughness.
79 citations
TL;DR: In this article, the similarity between Peridynamics and Smooth-Particle Hydrodynamics is studied, and it is shown that the discretized equations of both methods coincide if nodal integration is used.
79 citations
TL;DR: In this paper, the authors compared four cohesive zone models for modeling delamination caused by impact on composite materials and found that the use of strain-rate dependent material models significantly influences the numerical result.
49 citations
TL;DR: In this paper, the UHMWPE data range was extended at both ends by a factor of 3 for high and low shock pressures. But the results showed no effect of porosity on the results.
29 citations
TL;DR: In this article, the feasibility of different T-joint designs for application in aircraft composite fuel tanks which may be subjected to hydrodynamic ram loading was investigated, and the results showed that the hybrid metallic/composite Tjoint showed superior post-failure behavior compared to the state-of-the-art composite TJoint.
23 citations
01 Sep 2015
TL;DR: In this article, the influence of the specimen mounting and the specimen design on the test results was investigated, and the best signal was achieved using a mounting based on form fit, while three tested specimen designs all lead to a valid fracture behavior, but result in a different local strain rate.
Abstract: Split Hopkinson Tension Bar (SHTB) experiments can be used to test the material behavior with high strain rates in tension loading. The influence of the specimen mounting and the specimen design on the test results was investigated. Three mounting methods were tested. The best signal is achieve using a mounting based on form fit. The three tested specimen designs all lead to a valid fracture behavior, but result in a different local strain rate.
19 citations
TL;DR: In this article, a finite element model of a T-joint subjected to six different loading configurations is calibrated with the six different parameter sets, based on the available experimental data, recommendations are given for the type of test to choose for calibration of rate dependent strength parameters.
16 citations
01 Jan 2015
TL;DR: In this paper, the accuracy and convergence of the bond-based Peridynamic model with brittle failure, known as the prototype micro-brittle (PMB) model, was evaluated.
Abstract: This paper assesses the accuracy and convergence of the bond-based Peridynamic model with brittle failure, known as the prototype micro-brittle (PMB) model. We investigate the discrete equations of this model, suitable for numerical implementation. It is shown that the widely used discretization approach incurs rather large errors. Motivated by this observation, a correction is proposed, which significantly increases the accuracy by cancelling errors associated with the discretization. As an additional result, we derive equations to treat the interactions between differently sized particles, i.e., a non-homogeneous discretization spacing. This presents an important step forward for the applicability of the PMB model to complex geometries, where it is desired to model interesting parts with a fine resolution (small particle spacings) and other parts with a coarse resolution in order to gain numerical efficiency. Validation of the corrected Peridynamic model is performed by comparing longitudinal sound wave propagation velocities with exact theoretical results. We find that the corrected approach correctly reproduces the sound wave velocity, while the original approach severely overestimates this quantity. Additionally, we present simulations for a crack growth problem which can be analytically solved within the framework of Linear Elastic Fracture Mechanics Theory. We find that the corrected Peridynamics model is capable of quantitatively reproducing crack initiation and propagation.
12 citations
TL;DR: In this article, the T-joints were mounted in a servo-hydraulic machine and loaded in three different directions (rear, front, and side) and at three different loading velocities (0.5mm/s, 50 mm/s and 5000 mm /s).
6 citations
TL;DR: In this article, experiments on multiaxial fiber reinforced plastic laminates were performed to obtain calibration data for numerical fatigue analyses, and the presented simulation results display the fatigue behaviour of carbon fibre reinforced plastics for unidirectional loading conditions and a selected laminate.
Abstract: This paper describes experiments on multiaxial fibre reinforced plastic laminates, which were performed to obtain calibration data for numerical fatigue analyses. For this purpose, fatigue tests of laminates with multidirectional layers subjected to constant amplitude and block loading (0 ≤ R 1) were analysed. The presented simulation results display the fatigue behaviour of carbon fibre reinforced plastics for unidirectional loading conditions and a selected laminate.