Insertion of a Viscoelastic Layer to Reduce the Propagation of Energy by Vertical Impacts of Slamming in Planing Hull Vessels

2021 ◽  
Vol 889 ◽  
pp. 65-70
Author(s):  
Patrick Townsend ◽  
Juan Carlos Suárez ◽  
Paz Pinilla ◽  
Nadia Muñoz
Keyword(s):  
Viscoelastic Layer ◽  
Impact Machine ◽  
Acceleration Data ◽  
Weight Impact ◽  
Force Displacement ◽  
Data Reading ◽  
Vertical Impact ◽  
Interlaminar Damage

For the design of vessels built by GFRP laminates, an insert with a viscoelastic layer is proposed to reduce the spread of damage produced by the vertical impact of the ship's bottom with the sea or slamming phenomenon. Using vertical drops-weight impact machine that reproduce the energy inferred to the panel during navigation, the propagation of the damage of OoA cured prepreg panels is studied comparing it with modified panels with insertion of viscoelastic layer. The use of acceleration data reading allows the benefits of viscoelastic modification during impact to be quantified through the developed formulation. The force, displacement and energy returned by the panel after impact have also been quantified, which does not become intralaminar and interlaminar damage. It is shown that under 40 joules of impact, the viscoelastic sheet has its best ability to return energy and above 130 joules it loses its capacity.

Numerical Simulation of Low Impact Velocity Behaviour of Polymeric Syntactic Foam

2020 ◽  
Vol 12 (8) ◽  
pp. 1044-1049
Author(s):  
Yash M. Chordiya ◽  
Manmohan Dass Goel
Keyword(s):  
Impact Velocity ◽  
Reaction Force ◽  
Syntactic Foam ◽  
Time History ◽  
Material Model ◽  
Fe Model ◽  
Foam Material ◽  
Weight Impact ◽  
Force Time ◽  
Force Displacement

In this study a FE model is prepared for drop weight impact hammer testing of polymeric syntactic foam. The foam is modelled using crushable foam material and hammer is modelled using bilinear material model of LS-DYNA®. A series of simulation is performed by varying density of foam and impact velocity of hammer. Based on the prepared FE model and the force-displacement relation, energy absorption of the foam is computed and compared for three densities and three velocities. A comparative study is presented based on the displacement, reaction force-time history, and forcedisplacement behaviour.

Impact testing of concrete using a drop-weight impact machine

1989 ◽  
Vol 29 (1) ◽  
pp. 63-69 ◽  
Author(s):  
N. Banthia ◽  
S. Mindess ◽  
A. Bentur ◽  
M. Pigeon
Keyword(s):  
Impact Testing ◽  
Impact Machine ◽  
Drop Weight ◽  
Weight Impact

The Use of Viscoelastic Layers in GFRP, a New Vision of Planning Hull

2020 ◽  
Vol 847 ◽  
pp. 3-8
Author(s):  
Patrick Townsend ◽  
Juan Carlos Suárez ◽  
Nadia Muñoz ◽  
J. Rodríguez
Keyword(s):  
Strain Gauges ◽  
Viscoelastic Layer ◽  
Impact Machine ◽  
Maintenance And Repair ◽  
Micro Cracks ◽  
Laminated Panels ◽  
New Vision ◽  
Proposed Modification ◽  
Viscoelastic Layers ◽  
The Impact

The planning hull, are types of boats very used in our days, and require special maintenance and repair. It is proposed the insertion of a viscoelastic layer inside the laminated panels of the ships built with GFRP, to protect them from the impacts of slamming. Unmodified and modified laminate panels were manufactured to perform result comparisons. With the reproduction of the phenomenon of fatigue in the laboratory, testing them in the impact machine, the use of strain gauges and by characterization with fluorescent penetrating inks to observe the evolution of micro cracks. It is verified that the proposed modification is the future of shipbuilding of this type of vessel.

Digital differential hysteresis iimage processing displays what the microscope acquires but the eye can't see

1995 ◽  
Vol 53 ◽  
pp. 642-643
Author(s):  
Klaus-Ruediger Peters
Keyword(s):  
Image Processing ◽  
Visual System ◽  
High Precision ◽  
Image Data ◽  
Processing Technology ◽  
Output Data ◽  
Contrast Resolution ◽  
Pixel Intensity ◽  
Data Reading ◽  
Hysteresis Properties

Differential hysteresis processing is a new image processing technology that provides a tool for the display of image data information at any level of differential contrast resolution. This includes the maximum contrast resolution of the acquisition system which may be 1,000-times higher than that of the visual system (16 bit versus 6 bit). All microscopes acquire high precision contrasts at a level of <0.01-25% of the acquisition range in 16-bit - 8-bit data, but these contrasts are mostly invisible or only partially visible even in conventionally enhanced images. The processing principle of the differential hysteresis tool is based on hysteresis properties of intensity variations within an image.Differential hysteresis image processing moves a cursor of selected intensity range (hysteresis range) along lines through the image data reading each successive pixel intensity. The midpoint of the cursor provides the output data. If the intensity value of the following pixel falls outside of the actual cursor endpoint values, then the cursor follows the data either with its top or with its bottom, but if the pixels' intensity value falls within the cursor range, then the cursor maintains its intensity value.

Instrumentation for Measurement of Lingual Strength

1968 ◽  
Vol 11 (1) ◽  
pp. 189-193 ◽  
Author(s):  
Lois Joan Sanders
Keyword(s):  
Single Channel ◽  
Displacement Transducer ◽  
Tongue Pressure ◽  
Maximum Pressure ◽  
Research Use ◽  
Direct Writing ◽  
Significant Difference ◽  
Pressure Unit ◽  
Force Displacement ◽  
Consistent Response

A tongue pressure unit for measurement of lingual strength and patterns of tongue pressure is described. It consists of a force displacement transducer, a single channel, direct writing recording system, and a specially designed tongue pressure disk, head stabilizer, and pressure unit holder. Calibration with known weights indicated an essentially linear and consistent response. An evaluation of subject reliability in which 17 young adults were tested on two occasions revealed no significant difference in maximum pressure exerted during the two test trials. Suggestions for clinical and research use of the instrumentation are noted.

Sign in / Sign up

Export Citation Format

Share Document