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M. Gandelsman

Bio: M. Gandelsman is an academic researcher from Technion – Israel Institute of Technology. The author has contributed to research in topics: Izod impact strength test & Acceleration. The author has an hindex of 2, co-authored 2 publications receiving 38 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, a low velocity impact of carbon fiber reinforced epoxy (AS4/3502 by Hercules) was conducted with 48 and 40 layered beams of different combinations of 0°, 90°, 45° and −45° stacking sequences, and the acceleration pulse was analyzed in the frequency domain to determine the source of high frequency vibrations and a simple two-degrees-of-freedom model was used to distinguish between the force on the striker and the force applied to the beam.

31 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used subcritical instrumented impact tests to introduce small amounts of damage in the upper layer of beams mode of 32-ply NEMA/ASTM G-10 grade woven-glass reinforced epoxy resin.

7 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, the in-plane failure behavior of woven-fabric laminated composite plates has been studied under transverse central low-velocity point impact by using a modified Hertz law and a 3D transient finite element analysis code.

209 citations

Journal ArticleDOI
TL;DR: In this article, the impact behavior of reinforced concrete beams was investigated and a procedure to derive the shear force and bending moment diagrams was proposed to predict the position of the stationary points, which was proven yielding reasonable results in comparison with experimental and numerical results.

99 citations

Journal ArticleDOI
TL;DR: In this article, the impact performance assessment program (CSIPAP) suggests a multi-parameter methodology to gain further insight in the impact behavior of composite structures, including peak and critical force; critical and dissipated energy; contact duration and coefficient of restitution (COR), which is direct indication of effective structural stiffness; and residual stiffness (normalized contact duration) which yields a plot that bears a striking resemblance with the normalized Compression After Impact (CAI) strength.

89 citations

Journal ArticleDOI
TL;DR: In this article, the damage initiation behavior in polymer matrix laminated composite plates subjected to a transverse central low velocity point impact load was investigated using modified Hertz contact law and an in-house three-dimensional transient finite element analysis (FEA) code.
Abstract: An investigation was undertaken to study the damage initiation behavior in polymer matrix laminated composite plates subjected to a transverse central low velocity point impact load. Inplane failure of the layers in the form of matrix cracking/lamina splitting and delaminations were the primary objectives of the study. The study has been carried out using modified Hertz contact law and an inhouse three-dimensional transient finite element analysis (FEA) code. The inplane failure functions and the interlaminar failure functions have been predicted using quadratic failure criteria. The inhouse FEA code was validated with other analytical studies and the experimental results in our earlier work. The present studies have been carried out on different plain weave fabric laminated composite plates, simply supported on all four sides. For comparison, impact behavior of balanced symmetric crossply (CP) laminates made of unidirectional (UD) layers and UD composites has been included. The studies have been carried ...

52 citations

Journal ArticleDOI
TL;DR: In this article, a modified approach to the classic spring-mass model, which employs the notions of damaged stiffness and dissipated energy, leads to the derivation of approximate formulas that describe the peak force-energy curve.
Abstract: Recent research programs conducted on low-velocity impact events on composite structures have used force as the sole governing parameter and based their damage resistance and tolerance considerations on the peak recorded value. Understanding of other available parameters, such as contact duration and coefficient of restitution, which are related to the effective structural stiffness of the target, is fundamental in the design of a methodology for assessing impact performance and can offer greater insight in the interpretation of future research programs. An experimental database is gathered through drop tower impact testing by means of a rigid striker on clamped circular plates, for a particular polymer composite system. Several researchers have presented data showing that a critical value of the impact force for the onset of damage exists. Structural properties are hereby studied in both the sub- and supercritical regimes, which means for impact energy values below and above the damage threshold. A modified approach to the classic spring‐mass model, which employs the notions of damaged stiffness and dissipated energy, leads to the derivation of approximate formulas that describe the peak force-energy curve. In particular, the introduction of a dashpot to simulate the effect of damage greatly improves the accuracy of the model in the regime beyond the structural integrity threshold. A novel method to assess the residual performance of the damaged plate is developed, and it consists in low-energy, nondestructive impact testing, the results from which bear a striking resemblance with the curves obtained by compression after impact. MPACT tests can prove inherently difficult to understand because of the large number of parameters that play a key role in such events, particularly in the case of laminated composite structures due to their heterogeneous anisotropic nature and the complex failure modes that can occur. The current experimental investigation is conducted on square plates, supported over circular openings, having a quasi-isotropic [0/90/±45]4s stacking sequence. Such a configuration benefits from the axial symmetry of the circular geometry and the low degree of anisotropy of the laminate and thus facilitates the concentration on the mechanics of the impact event and the complex failure mechanisms. An extensive literature review has indicated that many questions still surround the impact response of composite plates. In particular, an ongoing debate exists on whether force or energy should be used to compare impact test results on different configurations, as well as whether a force- or energy-based criterion should be employed to predict the structural integrity threshold or uniquely and satisfactorily assess the state of damage in the plate. The aim of this paper is to show how governing parameters, such as force, energy, and structural stiffness vary between the subcritical and supercritical regimes and that peak force, although extremely valuable for predicting the damage threshold, cannot be used independently for investigating the impact performance of a composite structure. The use of an instrumented drop tower such as the General Re

52 citations