Dynamic Impact Testing of Polyurethane Energy Absorbing (EA) Foams

1994 ◽  
Author(s):  
David F. Sounik ◽  
Dennis W. McCullough ◽  
John L. Clemons ◽  
John L. Liddle
Keyword(s):  
Impact Testing ◽  
Dynamic Impact ◽  
Energy Absorbing

Mathematical modeling of elastoplastic deformation of tubular energy-absorbing elements under static and impact loading

2020 ◽  
pp. 78-82
Author(s):  
A.Р. Evdokimov ◽  
A.N. Gromyiko ◽  
A.A. Mironov
Keyword(s):  
Mathematical Modeling ◽  
Impact Loading ◽  
Elastoplastic Deformation ◽  
Shock Absorber ◽  
Analytical Models ◽  
Dynamic Impact ◽  
Shock Absorbers ◽  
Energy Absorbing ◽  
Absorbing Elements

Analytical models of static and dynamic impact elastoplastic deformation of tubular energy-absorbing elements constituting a tubular plastic shock absorber are proposed. The developed models can be used for the calculation and design of these shock absorbers. Keywords static and dynamic elastoplastic deformation, mathematical modeling, tubular energy-absorbing element, tubular plastic shock absorber, impact loading. [email protected]

Evaluation of Deformable Barrier Designs and Associated Compatibility Metrics in Full Frontal Impact Testing

2005 ◽  
Author(s):  
Steven Reagan ◽  
Xioawei Li ◽  
Saeed Barbat
Keyword(s):  
Computer Simulation ◽  
Research Laboratory ◽  
Time History ◽  
Impact Testing ◽  
Frontal Impact ◽  
Vehicle To Vehicle ◽  
Compression Stiffness ◽  
Structural Architecture ◽  
Transportation Research ◽  
Energy Absorbing

Several modifications to an existing deformable barrier are investigated for their ability to predict the presence of secondary energy absorbing structures (SEAS) using four deformable barrier designs with simulated impact by two vehicles. This study is motivated by the assumption that SEAS may enhance vehicle-to-vehicle compatibility and it is desirable to know if SEAS presence and its benefits are detectable through dynamic barrier testing. The considered barrier types are modifications of the Transportation Research Laboratory (TRL) barrier consisting of two layers, a front and rear. Each layer is 150mm thick with the first (front-most with respect to the vehicle) layer compression stiffness of 0.34 MPa and the second (rear-most) of 1.71 MPa. Proposed modifications to the (original, baseline) barrier are: 1. Increase the stiffness of a localized region of the front layer to 1.71 MPa (between ground heights of 330mm and 580mm). 2. Increase the depth of the second layer to 200 mm. 3. lncrease the depth of the second layer to 300 mm and use a single, non-segmented piece for the entire layer. The resulting four barrier configurations are all assumed to have 125 × 125 mm segmented “cells” supported by load time-history transducers. Computer simulation of impact by four vehicle models differing in mass and structural architecture is used. Four vehicle metrics intended to measure compatibility through impact with deformable barriers are used to quantify each barrier design’s ability to detect SEAS. Using the metrics outlined in this paper, a barrier design with stiffened rows three and four is best suited for SEAS detection. This conclusion is based on its sensitivity to four vehicle designs with and without SEAS as well as consistency of trends.

scholarly journals Numerical Simulation on In-plane Deformation Characteristics of Lightweight Aluminum Honeycomb under Direct and Indirect Explosion

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2222 ◽  
Author(s):  
Xiangcheng Li ◽  
Yuliang Lin ◽  
Fangyun Lu
Keyword(s):  
Plane Deformation ◽  
Buffering Capacity ◽  
Response Mode ◽  
Deformation Characteristics ◽  
Rigid Plate ◽  
Dynamic Impact ◽  
Aluminum Honeycomb ◽  
Energy Absorbing ◽  
Deformation Modes ◽  
Better Than

Lightweight aluminum honeycomb is a buffering and energy-absorbed structure against dynamic impact and explosion. Direct and indirect explosions with different equivalent explosive masses are applied to investigate the in-plane deformation characteristics and energy-absorbing distribution of aluminum honeycombs. Two finite element models of honeycombs, i.e., rigid plate-honeycomb-rigid plate (RP-H-RP) and honeycomb-rigid plate (H-RP) are created. The models indicate that there are three deformation modes in the X1 direction for the RP-H-RP, which are the overall response mode at low equivalent explosive masses, transitional response mode at medium equivalent explosive masses, and local response mode at large equivalent explosive masses, respectively. Meanwhile, the honeycombs exhibit two deformation modes in the X2 direction, i.e., the expansion mode at low equivalent explosive masses and local inner concave mode at large equivalent explosive masses, respectively. Interestingly, a counter-intuitive phenomenon is observed on the loaded boundary of the H-RP. Besides, the energy distribution and buffering capacity of different parts on the honeycomb models are discussed. In a unit cell, most of the energy is absorbed by the edges with an edge thickness of 0.04 mm while little energy is absorbed by the other bilateral edges. For the buffering capacity, the honeycomb in the X1 direction behaves better than that in the X2 direction.

scholarly journals Comparison of Lifetime of the PVD Coatings in Laboratory Dynamic Impact Test and Industrial Fine Blanking Process

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2154
Author(s):  
Josef Daniel ◽  
Radek Žemlička ◽  
Jan Grossman ◽  
Andreas Lümkemann ◽  
Peter Tapp ◽  
...  
Keyword(s):  
Impact Test ◽  
Impact Load ◽  
Protective Coatings ◽  
Impact Testing ◽  
Pvd Coatings ◽  
Dynamic Impact ◽  
Repeated Impact ◽  
Suitable Alternative ◽  
Fine Blanking ◽  
Blanking Process

Protective hard PVD coatings are used to improve the endurance of the tools exposed to repeated impact load, e.g., fine blanking punches. During the fine blanking process, a coated punch repeatedly impacts sheet metal. Thus, the coating which protects the punch surface is exposed to the dynamic impact load. On the other hand, the laboratory method of dynamic impact testing is well known and used for the development and optimization of protective coatings. This paper is focused on the comparison of tool life and lifetime of the industrial prepared PVD coatings exposed to repeated dynamic impact load in the industrial fine blanking process and the laboratory dynamic impact testing. Three different types of protective coatings were tested and the results were discussed. It was shown that the lifetime of coated specimens in both the fine blanking and the dynamic impact processes was influenced by similar mechanical properties of the protective coatings. The qualitative comparison shows that the lifetime obtained by the dynamic impact test was the same as the lifetime obtained by the industrial fine blanking process. The laboratory impact test appears to be a suitable alternative for the optimisation and development of protective PVD coatings for punches used in the industrial fine blanking process.

scholarly journals Dynamic impact testing of cellular solids and lattice structures: Application of two-sided direct impact Hopkinson bar

2021 ◽  
Vol 148 ◽  
pp. 103767
Author(s):  
Tomáš Fíla ◽  
Petr Koudelka ◽  
Jan Falta ◽  
Petr Zlámal ◽  
Václav Rada ◽  
...  
Keyword(s):  
Hopkinson Bar ◽  
Impact Testing ◽  
Lattice Structures ◽  
Cellular Solids ◽  
Direct Impact ◽  
Dynamic Impact

scholarly journals A tool for the evaluation of human lower arm injury: approach, experimental validation and application to safe robotics

Robotica ◽  
2015 ◽  
Vol 34 (11) ◽  
pp. 2499-2515 ◽  
Author(s):  
B. Povse ◽  
S. Haddadin ◽  
R. Belder ◽  
D. Koritnik ◽  
T. Bajd
Keyword(s):  
Mathematical Model ◽  
Experimental Validation ◽  
Human Impacts ◽  
Industrial Robot ◽  
Impact Testing ◽  
Impact Response ◽  
Dynamic Impact ◽  
Good Consistency ◽  
Impact Experiments ◽  
Human Injury

SUMMARYThis paper treats the systematic injury analysis of lower arm robot–human impacts. For this purpose, a passive mechanical lower arm (PMLA) was developed that mimics the human impact response and is suitable for systematic impact testing and prediction of mild contusions and lacerations. A mathematical model of the passive human lower arm is adopted to the control of the PMLA. Its biofidelity is verified by a number of comparative impact experiments with the PMLA and a human volunteer. The respective dynamic impact responses show very good consistency and support the fact that the developed device may serve as a human substitute in safety analysis for the described conditions. The collision tests were performed with two different robots: the DLR Lightweight Robot III (LWR-III) and the EPSON PS3L industrial robot. The data acquired in the PMLA impact experiments were used to encapsulate the results in a robot independent safety curve, taking into account robot's reflected inertia, velocity and impact geometry. Safety curves define the velocity boundaries on robot motions based on the instantaneous manipulator dynamics and possible human injury due to unforeseen impacts.

scholarly journals DYNAMIC IMPACT WEAR AND IMPACT RESISTANCE OF W-B-C COATINGS

2020 ◽  
Vol 27 ◽  
pp. 37-41
Author(s):  
Josef Daniel ◽  
Jan Grossman ◽  
Vilma Buršíková ◽  
Lukáš Zábranský ◽  
Pavel Souček ◽  
...  
Keyword(s):  
Impact Test ◽  
Impact Load ◽  
Protective Coatings ◽  
Impact Resistance ◽  
Impact Testing ◽  
The Novel ◽  
Test Results ◽  
Dynamic Impact ◽  
Impact Deformation ◽  
The Impact

Coated components used in industry are often exposed to repetitive dynamic impact load. The dynamic impact test is a suitable method for the study of thin protective coatings under such conditions. Aim of this paper is to describe the method of dynamic impact testing and the novel concepts of evaluation of the impact test results, such as the impact resistance and the impact deformation rate. All of the presented results were obtained by testing two W-B-C coatings with different C/W ratio. Different impact test results are discussed with respect to the coatings microstructure, the chemical and phase composition, and the mechanical properties. It is shown that coating adhesion to the HSS substrate played a crucial role in the coatings’ impact lifetime.

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