An Innovative Secondary Bonding of Sensors to Composite Structures for SHM Application

2018 ◽  
Vol 774 ◽  
pp. 516-522 ◽  
Author(s):  
Nan Yue ◽  
Zahra Sharif Khodaei ◽  
Ferri M.H. Aliabadi
Keyword(s):  
Environmental Conditions ◽  
Composite Structures ◽  
Test Procedures ◽  
Secondary Bonding

A novel procedure for installation of PZT sensors on composites is developed. The procedure is shown, through extensive tests, to be reliable, repeatable and repairable. The integrity of the bonded sensors are assessed following the RTCA DO-160 Environmental conditions and test procedures for airborne equipment. The developed bonding film has been tested on both thermoset and thermoplastic coupons and compared co-cured and secondary bonded sensors with epoxy.

Evaluation Of The Effectiveness Of Oil-Dispersing Chemicals

1969 ◽  
Vol 1969 (1) ◽  
pp. 199-207 ◽  
Author(s):  
T.A. Murphy ◽  
L.T. McCarthy
Keyword(s):  
Environmental Conditions ◽  
Salt Water ◽  
Water Solution ◽  
Field Tests ◽  
Field Performance ◽  
Standard Test ◽  
Oil Composition ◽  
Test Procedures ◽  
Test Conditions ◽  
Limited Precision

Abstract A procedure for evaluating the effectiveness of oil-dispersing chemicals has been developed. Using the apparatus originally designed for the Navy specification for solvent-emulsifiers, test conditions were adapted to correspond more closely to typical environmental conditions. Test conditions having the greatest effect on dispersant performance included: type of oil, composition of salt water solution, degree of agitation of chemical/oil mixture, and the degree of contact between chemical and oil prior to agitation. Results from this modified procedure, the Simulated Environmental Tank (SET) Test, correspond well with results from simple field tests. Field tests have limited precision and reproducibility. This lack of a reliable index of field performance with which to compare laboratory results hinders refinement of standard test procedures. The SET Test, which produces results corresponding favorably with field performance, to the extent field performance can be determined, and which simulates typical environmental conditions, is proposed as a meaningful interim solution to this problem of dispersant evaluation.

scholarly journals Physicochemical Assessment of the Biodegradability of Agricultural Nonwovens Made of PLA

2021 ◽  
Vol 29 (1(145)) ◽  
pp. 26-34
Author(s):  
Patrycja Miros-Kudra ◽  
Karolina Gzyra-Jagieła ◽  
Michał Kudra
Keyword(s):  
Mass Loss ◽  
Natural Environment ◽  
Environmental Conditions ◽  
Circular Economy ◽  
Polymer Materials ◽  
Gel Chromatography ◽  
Test Procedures ◽  
Biodegradation Process ◽  
Petroleum Derivatives ◽  
Loss Determination

Compostable biodegradable plastics are an ecological alternative to traditional products based on petroleum derivatives, whose post-use waste may pollute the natural environment. Modern polymer materials show the functional properties of plastics obtained by conventional methods, but they also may be degraded as a result of biochemical transformations in composting. This allows such materials to be included in the scheme of the currently implemented circular economy, which does not generate post-consumer waste. This paper presents methods for the assessment of the biodegradation process of selected agricultural nonwovens produced from commercial PLA 6252D polylactide, supplied by Nature Works® LLC, USA. The agricultural nonwovens tested, obtained by the spun-bond technique, were characterised by different degrees of crystallinity in the range from 11.1% to 31.4%. Biodegradation tests were carried out as simulated aerobic composting while maintaining constant environmental conditions in accordance with test procedures based on PN-EN/ISO standards using the method of sample mass loss determination. Gel chromatography (GPC/SEC) and FTIR spectroscopy were also applied to assess the degree of biodegradation. The aim of this study was to evaluate the effect of the crystallinity of nonwoven made of PLA 6252 D on its degradation in a compost environment.

scholarly journals Powder Epoxy for One-Shot Cure, Out-of-Autoclave Applications: Lap Shear Strength and Z-Pinning Study

2021 ◽  
Vol 5 (9) ◽  
pp. 225
Author(s):  
Thomas Noble ◽  
James R. Davidson ◽  
Christophe Floreani ◽  
Ankur Bajpai ◽  
William Moses ◽  
...  
Keyword(s):  
Shear Strength ◽  
Composite Structures ◽  
Shear Failure ◽  
Image Correlation ◽  
Premature Failure ◽  
Adhesive Film ◽  
Lap Shear Strength ◽  
Lap Shear ◽  
Out Of Autoclave ◽  
Secondary Bonding

Large composite structures manufactured out-of-autoclave require the assembly and bonding of multiple parts. A one-shot cure manufacturing method is demonstrated using powder epoxy. Lap shear plates were manufactured from powder epoxy and glass fiber-reinforced plastic with four different bonding cases were assessed: secondary bonding using standard adhesive film, secondary bonding using powder epoxy, co-curing, and co-curing plus a novel Z-pinning method. This work investigates the lap shear strength of the four cases in accordance with ISO 4587:2003. Damage mechanisms and fracture behavior were explored using digital image correlation (DIC) and scanning electron microscopy (SEM), respectively. VTFA400 adhesive had a load at break 24.8% lower than secondary bonding using powder epoxy. Co-curing increased the load at break by 7.8% compared to powder epoxy secondary bonding, with the co-cured and pinned joint resulting in a 45.4% increase. In the co-cured and co-cured plus pinned cases, DIC indicated premature failure due to resin spew. SEM indicated shear failure of resin areas and a large amount of fiber pullout in both these cases, with pinning delaying fracture phenomena resulting in increased lap joint strength. This highlights the potential of powder epoxy for the co-curing of large composite structures out-of-autoclave.

Experimental Procedures Used in the Development of Oil Retention Boom Designs

1972 ◽  
Vol 9 (03) ◽  
pp. 317-332
Author(s):  
E. R. Miller ◽  
W. T. Lindenmuth ◽  
W. E. Lehr ◽  
R. N. Abrahams
Keyword(s):  
Environmental Conditions ◽  
Weber Number ◽  
Full Scale ◽  
Design Criteria ◽  
Mooring System ◽  
Test Procedures ◽  
Towing Tank ◽  
Oil Retention ◽  
Scaling Parameters ◽  
Scale Data

The experimental procedures used in the development of oil retention boom design criteria are presented in detail. Emphasis is placed on the procedures used to determine the oil containment ability and structural loads on the boom as a function of environmental conditions. The critical scaling parameters for oil containment tests are presented and the test procedures which have been developed are described. It is concluded that it is critical to scale both Froude and Weber number. Tests to determine structural loads can be conducted using standard ship towing tank procedures. However, it is necessary to scale the elastic properties of the boom and its mooring system. There are uncertainties with respect to some parameters which cannot be properly scaled in oil containment tests. Thus, carefully conducted full-scale trial results are required. Available procedures and current plans to obtain full-scale data are presented.

Energy Absorbability of Large Scale Inflatable Composite Structures

2006 ◽  
Author(s):  
Claudia Quigley ◽  
Karen Buehler ◽  
Paul Cavallaro ◽  
Ali Sadegh
Keyword(s):  
Composite Structures ◽  
Large Scale ◽  
Scaling Laws ◽  
Structural Elements ◽  
Functional Requirements ◽  
Test Procedures ◽  
Governmental Agencies ◽  
Sufficient Energy ◽  
Strength And Stiffness ◽  
Energy Absorbing

Airbeams, inflatable composite structures, have traditionally been used solely as structural elements. Modeling and test procedures have been under development by academia, industry and governmental agencies to predict and evaluate an airbeam's structural properties. However, the pneumatic component that gives airbeams their strength and stiffness also provides airbeams the capability to absorb energy. Test procedures and scaling laws that can be used to evaluate the energy absorbing capacity of these structural elements will be described and evaluated. Test data will show that airbeams can reliably absorb sufficient energy for applications such as a pneumatic fender and meet other functional requirements. The paper will also describe textile considerations and other material properties that will enable this application to be successful.

A Compact Test Instrument for Determining the Indentation Failure of Elastomers

1964 ◽  
Vol 37 (1) ◽  
pp. 14-27 ◽  
Author(s):  
Daniel I. Livingston ◽  
Leurene E. Hildenbrand
Keyword(s):  
Composite Structures ◽  
Polymeric Materials ◽  
Test Procedures ◽  
Test Region ◽  
Dial Gage ◽  
Indentation Tests ◽  
Puncture Force ◽  
Failure Properties ◽  
Relationship Of ◽  
The Relationship

Abstract There exists a considerable area in which conventional methods for the evaluation of physical properties of polymeric materials are either inconvenient or practically impossible. This is the case for very small specimens, irregularly-shaped regions, or composite structures of vulcanized elastomers. Here micro test procedures are indicated, and tests of local indentation are particularly appropriate; for when the indenter diameter is small compared to the dimensions of the test region, the results become independent of the dimensions, and little or no special preparation of the sample is required. We have extended the scope of indentation tests, from the measurement of stress-strain properties alone, to include the capability of securing measurements of the ultimate strength and indentation. These indentation failure properties should be pertinent to the service life of many fabricated articles. This paper describes the use of a compact instrument designed to perform indentation tests up to failure in a rapid and reliable fashion. A synchronous motor raises the test specimen against the indenter, a flat-ended cylinder of 0.014-inch diameter, until failure occurs, whereupon the machine stops automatically. Readings of a dial gage dynamometer and revolution counter on the platform drive are converted into puncture force and depth. Applications of the instrument to the evaluation of some typical reinforced rubbers have been illustrated, and the relationship of these measurements to other mechanical properties discussed.

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