Deformation and fracture of adhesive layers constrained by plastically-deforming adherends

The use of an embedded-process zone (EPZ) model to investigate the mode I cohesive parameters for plastically-deforming, adhesively-bonded joints is demonstrated in this paper. It is shown that for the particular systems investigated, the cohesive parameters are consistent with an adhesive layer deforming in accordance with its bulk constitutive properties (as constrained by the adherends). In other words, these systems provide examples where the cohesive tractions exerted by an adhesive layer can be calculated simply from considerations of the constrained deformation of the adhesive. Consistent with such calculations, the peak stress in the adhesive layer decreases as the level of the constraint decreases (either with an increase in the thickness of the adhesive layer or with a decrease in the thickness of the adherends). It is also shown that owing to a compensating effect in which the critical displacement for failure varies with the constraint, the energy absorbed by the adhesive layer (the 'intrinsic' toughness of the joint) is essentially independent of the geometry in these systems.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43697/1/10861_2004_Article_vsp_01694243_v14n13_s1.pd

Determining the toughness of plastically deforming joints

An analysis is presented for the fracture of an adhesively bonded double-cantilever beam that fails with extensive plastic deformation of the adherends. The analysis permits a value for the toughness of the joint to be distinguished from the energy absorbed by the plastic deformation. Specifically, this value for toughness can be determined from post-fracture observations of the deformation and from a knowledge of the constitutive properties of the adherends. The analysis has been used to determine experimentally the toughness of plastically deforming joints formed using three different adhesives to bond a series of different thicknesses of aluminium and steel. In each case, it was found that, despite large differences in the extent of deformation, the value for toughness was dependent only on the materials used to form the joint. The toughness was independent of the thickness of the adherends.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44745/1/10853_2004_Article_175816.pd

The Static Failure of Adhesively Bonded Metal Laminate Structures: A Cohesive Zone Approach

Data on distribution, ecology, biomass, recruitment, growth, mortality and productivity of the West African bloody cockle Anadara senilis were collected at the Banc d'Aguuin, Mauritania, in early 1985 and 1986. Ash-free dry weight appeared to be correlated best with shell height. A. senilis was abundant on the tidal flats of landlocked coastal bays, but nearly absent on the tidal flats bordering the open sea. The average biomass for the entire area of tidal flats was estimated at 5.5 g·m−2 ash-free dry weight. The A. senilis population appeared to consist mainly of 10 to 20-year-old individuals, showing a very slow growth and a production: biomass ratio of about 0.02 y−1. Recruitment appeared negligible and mortality was estimated to be about 10% per year. Oystercatchers (Haematopus ostralegus), the gastropod Cymbium cymbium and unknown fish species were responsible for a large share of this. The distinction of annual growth marks permitted the assessment of year-class strength, which appeared to be correlated with the average discharge of the river Senegal. This may be explained by assuming that year-class strength and river discharge both are correlated with rainfall at the Banc d'Arguin.

Co-rotational Formulation for Bonded Joint Finite Elements

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97052/1/AIAA2012-1449.pd