Edge disbond detection of carbon/epoxy repair patch on aluminum using thermography

2019 ◽  
Vol 179 ◽  
pp. 41-53 ◽  
Author(s):  
Morteza Moradi ◽  
Mir Saeed Safizadeh
Keyword(s):  
Repair Patch ◽  
Disbond Detection

scholarly journals Repair of abasic sites by mammalian cell extracts

1994 ◽  
Vol 304 (3) ◽  
pp. 699-705 ◽  
Author(s):  
G Frosina ◽  
P Fortini ◽  
O Rossi ◽  
F Carrozzino ◽  
A Abbondandolo ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Excision Repair ◽  
Chinese Hamster ◽  
Pyrimidine Dimer ◽  
Repair Synthesis ◽  
Repair Patch ◽  
Cell Extracts ◽  
Pyrimidine Dimers ◽  
Ap Sites ◽  
Ap Site

Hamster cell extracts that perform repair synthesis on covalently closed circular DNA containing pyrimidine dimers, were used to study the repair of apurinic/apyrimidinic (AP) sites and methoxyamine (MX)-modified AP sites. Plasmid molecules were heat-treated at pH 5 and incubated with MX when required. The amount of damage introduced ranged from 0.2 to 0.9 AP sites/kb. Extracts were prepared from the Chinese hamster ovary CHO-9 cell line and from its derivative, 43-3B clone which is mutated in the nucleotide excision repair (NER) ERCC1 gene. AP and MX-AP sites stimulated repair synthesis by CHO-9 cell extracts. The level of synthesis correlated with the number of lesions and was of similar magnitude to the repair stimulated by 4.3 u.v. photoproducts/kb. Repair of AP and MX-AP sites was faster than the repair of u.v. damage and was independent of ERCC1 gene product. The high level of repair replication was due to a very efficient and rapid incision of plasmids carrying AP or MX-AP sites, performed by abundant AP endonucleases present in the extract. The calculated average repair patch sizes were: 7 nucleotides per AP site; 10 nucleotides per MX-AP site; 28 nucleotides per (6-4) u.v. photoproduct or cyclobutane pyrimidine dimer. The data indicate that AP and MX-AP sites are very efficiently repaired by base-excision repair in mammalian cells and suggest that MX-AP sites may also be processed via alternative repair mechanisms.

Electromechanical Analysis of a Piezoelectric Instrumented Composite Bonded Repair Patch

2020 ◽  
pp. 771-778
Author(s):  
T. S. Koko ◽  
N. Mrad ◽  
B. K. Gallant ◽  
T. Dunbar ◽  
P. Masson
Keyword(s):  
Repair Patch ◽  
Bonded Repair

scholarly journals Investigating the Effect of Stepped Scarf Repair Ratio in Repaired CFRP Laminates under Compressive Loading

2020 ◽  
Vol 4 (4) ◽  
pp. 153
Author(s):  
Spyridon Psarras ◽  
Theodoros Loutas ◽  
Magdalini Papanaoum ◽  
Orestis Konstantinos Triantopoulos ◽  
Vasilis Kostopoulos
Keyword(s):  
Numerical Models ◽  
Compressive Loading ◽  
Composite Plates ◽  
Step Length ◽  
Critical Threshold ◽  
Cfrp Laminates ◽  
Threshold Size ◽  
Repair Patch ◽  
Parametric Studies ◽  
Strength And Stiffness

In this work the effectiveness of stepped repairs to damaged fiber reinforced composite materials is investigated by using previously validated numerical models which were compared with tested repaired composite plates. Parametric studies were carried out in order to assess the scarf ratio (i.e., step length to ply thickness ratio) influence on ultimate forces, displacements, stresses and stiffnesses. FE models with repair scarf ratios varying from the value of 20 to the value 60 with a step increase of 10 were developed. The numerical models allowed a direct comparison of the influence that the scarf ratio had to the strength and stiffness restoration of the repaired composite structure. The study verifies that the restoration of the strength of a damaged laminate depends largely on the size of the repair patch. Generally, the bigger the size of a patch, the stronger the repaired structure is, up to a critical threshold size. To maximize the strength restoration, it is advised that the number of steps in each patch are no less than the number of plies on the base laminate.

Optimization of a composite scarf repair patch under tensile loading

2009 ◽  
Vol 40 (12) ◽  
pp. 1921-1930 ◽  
Author(s):  
T.D. Breitzman ◽  
E.V. Iarve ◽  
B.M. Cook ◽  
G.A. Schoeppner ◽  
R.P. Lipton
Keyword(s):  
Tensile Loading ◽  
Repair Patch
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