The Effect of Temperature, Thickness, and Working Time on Adhesive Properties

2018 ◽  
Author(s):  
Nicholas Aerne ◽  
John P. Parmigiani
Keyword(s):  
Cantilever Beam ◽  
Design Process ◽  
Working Time ◽  
Effect Of Temperature ◽  
Control Group ◽  
Mode I ◽  
Mode Ii ◽  
Adhesive Properties ◽  
Loading Modes ◽  
Mode Ii Loading

The need for lightweight components and non-destructive fastening techniques has led to the growth of adhesive use in many industries. Modeling the behavior of adhesives in fastening joints can help in the design process to make an optimized joint. To optimize joints in the design process, the loading conditions, environmental conditions of service, thickness of bond, and bonding procedures all need to be refined for the adhesive of interest. However, in available technical data sheets of adhesives provided by manufactures there is a gap in what is sufficient to accurately model and predict the behavior of real-world adhesive conditions. This body of research presents the results of the effects of temperature, thickness, and working time on adhesive properties. These effects can be observed with test specimens from the loading modes of interest. The loading modes of interest are mode I and mode II loading for the current study. The specimen for mode I loading is the Double Cantilever Beam, and for mode II loading is the Shear Loaded Dual Cantilever Beam. The effect of temperature will be tested by testing each specimen at −20°C, 20°C, and 40°C. Two bond thicknesses for adhesive thickness effects were tested. The working time had a control group bonded in the recommended working time and an expired working time group where the specimens were not joined until 10 minutes had passed from the recommended working time. Triplicates of each specimen at the respective conditions were tested. The adhesive selected for this research was Plexus MA832. The results of the experiment show that adhesive factors such as temperature, thickness, and working time can have degrading effects on adhesive performance in mode I and mode II.

Adhesive Properties Subject to Temperature Testing for Cohesive Zone Modeling

2017 ◽  
Author(s):  
Nick Aerne ◽  
Taylor J. Rawlings ◽  
John P. Parmigiani
Keyword(s):  
Cantilever Beam ◽  
High Temperatures ◽  
Material Properties ◽  
Low Temperatures ◽  
Cohesive Zone ◽  
Cohesive Strength ◽  
Mode I ◽  
Mode Ii ◽  
Zone Model ◽  
Adhesive Properties

The growth of lightweight components and need for non-destructive fastening techniques leads to the use of adhesives in many industries. Modeling the behavior of adhesives in fastening joints can help in the design process to make an optimized joint, with minimal waste. However, in available material properties provided by manufactures of adhesives there is a gap in what is sufficient to accurately model and predict the behavior of real-world adhesive conditions. An adhesive joint may be loaded in mode I, mode II, mode III, or a combination of these in service. In components with outdoor application the ambient temperature outside in many regions can vary to below freezing to over 40 °C. The environmental conditions at these temperatures may influence the adhesive material properties. This body of research presents the results of adhesive properties subject to temperature testing. The needed material properties to compose an accurate model have been shown to be the mode I cohesive strength, mode I cohesive toughness, mode II cohesive strength, and mode II cohesive toughness. These properties can be measured with a test specimen designed to isolate that loading mode and condition. The specimens used are the Dog Bone Tensile Specimen (DBTS), the Double Cantilever Beam (DCB), Shear Loaded Dual Cantilever Beam (SLDCB), and Double Lap Shear (DLS). The effect of temperature will be tested by testing each specimen at −30°C, 20°C, and 45°C. Triplicates of each specimen at the respective temperature were tested. These results will be used in a cohesive zone model that will be validated with additional testing. The results from the two tested adhesives, Plexus MA832 and Pliogrip 7779/220, indicate these temperature conditions can change the cohesive strength in mode I by −60 to −40 % and mode II by −13 to 2% when at high temperatures (HT). The cohesive toughness in mode I by −40 to −20% and mode II by −40 to −2% when at high temperatures. The cohesive strength in mode I by −50 to 15% and mode II by 8% to 60% when at low temperatures (LT). The cohesive toughness in mode I by −70 to −20% and mode II by 30 to 60% when at low temperatures. As compared with those tested at room temperature (RT). The ranges here represent the response for both adhesives.

Microstructural Effects on Fracture Toughness of Polycrystalline Ceramics in Combined Mode I and Mode II Loading

1989 ◽  
Vol 111 (1) ◽  
pp. 174-180 ◽  
Author(s):  
D. Singh ◽  
D. K. Shetty
Keyword(s):  
Fracture Toughness ◽  
Mode I ◽  
Mode Ii ◽  
Mixed Mode Fracture ◽  
Transgranular Fracture ◽  
Pure Mode ◽  
Polycrystalline Alumina ◽  
Polycrystalline Ceramics ◽  
Mode Ii Loading ◽  
Combined Mode

Fracture toughness of polycrystalline alumina and ceria partially stabilized tetragonal zirconia (CeO2-TZP) ceramics were assessed in combined mode I and mode II loading using precracked disk specimens in diametral compression. Stress states ranging from pure mode I, combined mode I and mode II, and pure mode II were obtained by aligning the center crack at specific angles relative to the loading diameter. The resulting mixed-mode fracture toughness envelope showed significant deviation to higher fracture toughness in mode II relative to the predictions of the linear elastic fracture mechanics theory. Critical comparison with corresponding results on soda-lime glass and fracture surface observations showed that crack surface resistance arising from grain interlocking and abrasion were the main sources of the increased fracture toughness in mode II loading of the polycrystalline ceramics. The normalized fracture toughness for pure mode II loading, (KII/KIc), increased with increasing grain size for the CeO2-TZP ceramics. Quantitative fractography confirmed an increased percentage of transgranular fracture of the grains in mode II loading.

scholarly journals Fracture Behavior of Carbon-Epoxy under Different Loading

2020 ◽  
Vol 9 (3) ◽  
pp. 1145-1149
Keyword(s):  
Fracture Surface ◽  
Strain Energy ◽  
Fracture Behavior ◽  
Strain Energy Release Rate ◽  
Strain Energy Release ◽  
Mode I ◽  
Mode Ii ◽  
New Materials ◽  
The Common ◽  
Mode Ii Loading

Delamination is the common failures of composite material attributed to various reasons, most importantly the potential stiffness degradation leading to small flaws and subsequently theypropagate, and it becomes essential to characterize the new materials for interlaminar fracture. For the present study Carbon /epoxy system of IM7/8552 was investigated under mode I and mode II loading. Material was formed into unidirectional laminates with Teflon inserts at its mid length. The specimens were machined according to ASTM standards, Tests were executed on a quasi-static Intron 8225, with load control at 5 mm/ min and 2 m/min for the mode -I and mode-II respectively. The strain energy release rate was found to be GIC=0.266 kJ/m2 and GIIC=0.687 kJ/m2 . Fiberbridging was prominently absent in the DCB samples Examination of the fracture surface by SEM at SAIF, in IIT{M) and the nature of the fracture surface revealed the typical failure mechanism pertaining to mode-I and mode-II failuremechanisms

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