Stress Analyses and Structural Modifications of Fabric Composite Seams

2002 ◽  
Author(s):  
Wenzhong Tang ◽  
Michael Keefe
Keyword(s):  
Numerical Data ◽  
Strength Degradation ◽  
Test Results ◽  
Adhesively Bonded ◽  
Structural Modifications ◽  
Composite Layers ◽  
Fabric Composite ◽  
Out Of Plane ◽  
Coated Fabrics ◽  
Stress Analyses

An adhesively bonded seam is a common method of joining coated fabrics in the manufacturing of inflatables. In this paper, Nylon and Polyester seams are studied both experimentally and numerically. In the numerical analyses, the seam components are described with layered models containing fabric composite layers. The in-plane and out-of-plane elastic constants of the fabric composite layers are derived using the crimp model and a stacked model respectively. An existing finite element code, ANSYS 5.7 is used to perform two-dimensional stress analyses of the seams under tension. In the analyses, a stress concentration factor is defined to evaluate the strength of the seams in comparison with their base fabric laminates. Numerical data show that Nylon seams are almost as strong as their base laminate but there is strength degradation in Polyester seams, which agrees well with test results. Finally, two structural modifications are proposed to improve the strength of the Polyester seams. The modifications are evaluated by both simulations and tests.

Stress analysis and structural modifications of a polyester double-tape seam

2003 ◽  
Vol 217 (2) ◽  
pp. 101-112
Author(s):  
W Tang ◽  
M Keefe
Keyword(s):  
Finite Element ◽  
Stress Analysis ◽  
Strength Loss ◽  
Two Dimensional ◽  
Finite Element Code ◽  
Structural Modifications ◽  
Composite Layers ◽  
Fabric Composite ◽  
Out Of Plane ◽  
Layered Models

In this paper, a polyester double-tape seam is studied both experimentally and numerically. In the numerical analysis, the seam components are described with layered models containing fabric composite layers. The in-plane and out-of-plane elastic constants of the fabric composite layers are derived using a crimp model and a stacked model respectively. An existing finite element code, ANSYS 5.7, is used to perform two-dimensional stress analysis of the seam under tension. Numerical results identified the stress concentration causing strength loss in the seam. Finally, two structural modifications are proposed to improve the seam strength. The modifications are evaluated by both simulations and tests.

Experimental Study on Steel Frames Infilled with Sandwich Composite Panels

2011 ◽  
Vol 243-249 ◽  
pp. 499-505
Author(s):  
Can Xing Qiu ◽  
He Tao Hou ◽  
Wei Long Liu ◽  
Ming Lei Wu
Keyword(s):  
Seismic Design ◽  
Steel Frames ◽  
Strength Degradation ◽  
Hysteretic Behavior ◽  
Sandwich Composite ◽  
Viscous Damping ◽  
Test Results ◽  
Ductility Index ◽  
Damage Process ◽  
Seismic Behaviors

A model of full scale one-bay, one storey was tested under low cyclic loading in order to study the hysteretic behavior of steel frames with sandwich composite (SC) panels. According to the failure pattern and damage process of test specimen, seismic behaviors were evaluated. Hysterics loops, skeleton curves, curves of strength degradation, and curves of stiffness degradation, ductility index and viscous damping coefficient were analyzed. Test results show that the failures of panels mainly occurred around the embedded parts, but compared with traditional panels and walls, SC panels exhibit a better integration. The connection between panel and steel frame is vital to the mutual work of the two parts. Finally, seismic design recommendations based on the analysis of ductility index and energy dissipation of the structures are presented.

TEST RESULTS OF 60-cm BORE Nb3Sn TEST MODULE COIL (TMC-I) IN THE CLUSTER TEST FACILITY

1984 ◽  
Vol 45 (C1) ◽  
pp. C1-101-C1-104
Author(s):  
T. Ando ◽  
S. Shimamoto ◽  
T. Hiyama ◽  
H. Tsuji ◽  
Y. Takahashi ◽  
...  
Keyword(s):  
Time Constant ◽  
Decay Time ◽  
Superconducting State ◽  
Heat Input ◽  
Test Facility ◽  
Test Results ◽  
Normal Zone ◽  
Out Of Plane ◽  
Force Mode ◽  
Test Module

An extended test of a 60-cm-bore Nb3Sn coil (TMC-I), constructed as a development of superconducting toroidal coil in tokamak machine, has been carried out in the cluster test facility. A 192-cm-length (one turn) normal zone, nucleated by a heat-input in the innermost turn, is recovered to superconducting state at 6 kA and 10 T. For the manual dump with a decay time constant of 6.6 sec (B = 1.0 T/sec), no damage is found on the TMC-I. In addition, a out-of-plane force mode operation, using one of the cluster test coils, is done with no trouble. With these good results, the first stage in TMC-I test was completed. And as the next stage, up-grading the cluster test facility for further TMC-I test in 11 T is now going ahead.

Estimation of Seismic Energy Dissipation for Steel Slit Shear Walls Considering Out-of-Plane Buckling

2021 ◽  
Author(s):  
Yiming Ma ◽  
Liusheng He ◽  
Ming Li
Keyword(s):  
Energy Dissipation ◽  
Shear Walls ◽  
Seismic Energy ◽  
Thickness Ratio ◽  
Design Parameters ◽  
Test Results ◽  
Loading Test ◽  
Aspect Ratios ◽  
Out Of Plane ◽  
Energy Dissipation Capacity

Steel slit shear walls (SSSWs), made by cutting slits in steel plates, are increasingly adopted in seismic design of buildings for energy dissipation. This paper estimates the seismic energy dissipation capacity of SSSWs considering out-of-plane buckling. In the experimental study, three SSSW specimens were designed with different width-thickness ratios and aspect ratios and tested under quasi-static cyclic loading. Test results showed that the width-thickness ratio of the links dominated the occurrence of out-of-plane buckling, which produced pinching in the hysteresis and thus reduced the energy dissipation capacity. Out-of-plane buckling occurred earlier for the links with a larger width-thickness ratio, and vice versa. Refined finite element model was built for the SSSW specimens, and validated by the test results. The concept of average pinching parameter was proposed to quantify the degree of pinching in the hysteresis. Through the parametric analysis, an equation was derived to estimate the average pinching parameter of the SSSWs with different design parameters. A new method for estimating the energy dissipation of the SSSWs considering out-of-plane buckling was proposed, by which the predicted energy dissipation agreed well with the test results.

A Design Guide for Estimating Speed Made Good for a Sailing Yacht

1981 ◽  
Author(s):  
Deborah W. Berman
Keyword(s):  
Numerical Data ◽  
Quantitative Information ◽  
Test Results ◽  
Standard Series ◽  
Hull Form ◽  
Design Guide ◽  
Current Design ◽  
Sailing Yacht ◽  
Pencil And Paper ◽  
Selection Of

This study develops a simplified comparative procedure for use in preliminary yacht design to predict Equilibrium sideforce, resistance, leeway angle and speed made good to windward for a canoe hull sailing yacht within specific form parameters on any of five standard series keels. These forces, angles and speeds are predicted for any yacht hull resembling one of nine models - ranging from light to medium-heavy length to displacement ratio - (190 to 351) - of the Delft Systematic Series for which there is numerical data. The forces are calculated at speed to length ratio of 1. 3 and heel angle of 30° to enable the designer to make use of existing comparative sail plan and rigging data. The five keels of varying aspect and area ratio, spanning current design practice, are part of a matrix developed at the Davidson Laboratory. In this paper, a canoe yacht hull form similar to Model 7 of the Delft Series is tank tested on 3 Standard Series keels and compared to results obtained from testing a 5.5 m hull, which is similar to Model 8, on the same keels. A prediction procedure is developed and checked against test results. A few Equations, selected values from included tabulations, a calculator, pencil and paper will yield quantitative information for the yacht designer in the selection of a keel for the hull of a sailing yacht.

Experimental study of the out-of-plane dynamic behaviour of adhesively bonded composite joints using split Hopkinson pressure bars

2018 ◽  
Vol 52 (21) ◽  
pp. 2875-2885 ◽  
Author(s):  
S Sassi ◽  
M Tarfaoui ◽  
H Benyahia
Keyword(s):  
Strain Rate ◽  
Dynamic Behaviour ◽  
Dynamic Compression ◽  
Strain Rates ◽  
Bonded Joints ◽  
Adhesively Bonded ◽  
Adhesively Bonded Joints ◽  
Out Of Plane ◽  
Bonded Composite ◽  
Strong Material

The effect of the strain rate on the mechanical behavior and the damage of adhesively bonded joints is one of the most important factors to consider in designing them. Vast research has been carried out on the dynamic behaviour of adhesives at different strain rates; however, the investigation about the dynamic behaviour of the adhesively bonded joints is limited. In this paper, the main objective is to study and assess the effect of the strain rate on the out-of-plane mechanical behaviour of adhesively bonded joints under dynamic compression using Hopkinson bars. These joints are studied using glass/vinylester composite materials which are commonly used in naval applications. The experimantal results have shown a strong material sensitivity to strain rates. Moreover, damage investigations have revealed that the failure mainly occurred in the adhesive/adherent interface because of the brittle nature of the polymeric adhesive. Results have shown good agreement with the dependency of the dynamic parameters on strain rates.

scholarly journals Detection of debonding in adhesive joints using Lamb wave propagation

2019 ◽  
Vol 262 ◽  
pp. 10012
Author(s):  
Magdalena Rucka ◽  
Erwin Wojtczak ◽  
Jacek Lachowicz
Keyword(s):  
Wave Propagation ◽  
Lamb Waves ◽  
Visual Assessment ◽  
Guided Wave ◽  
Steel Plates ◽  
Experimental Investigations ◽  
Mechanical Degradation ◽  
Adhesively Bonded ◽  
Destructive Testing ◽  
Out Of Plane

Adhesively bonded joints are widely used in many branches of industry. Mechanical degradation of this type of connections does not have significant symptoms that can be noticed during visual assessment, so non-destructive testing becomes a very important issue. The paper deals with experimental investigations of adhesively bonded steel plates with different defects. Five samples (an intact one and four with damages in the form of partial debonding) were prepared. The inspection was conducted with the use of guided wave propagation method. Lamb waves were excited at one point of the sample, whereas the out-of-plane velocity signals were recorded in a number of points spread over the area of overlap. The processing of signals consisted of calculations of weighted root mean square (WRMS). The results of the analysis showed that the WRMS maps allow for identification and determination of size and shape of debonding areas.

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