differently in different joints.See Guide D4896for further discussion of the concepts relative to interpretation of adhesive bonded single lap joints.
5.Apparatus
5.1Testing Machine,conforming to the requirements of and having the capabilities of the machine prescribed in Test Method D1002.Likewi the grips are capable of curely grasping the specimen throughout the test without allowing the specimen to slip.The grips are also lf-aligning.
5.2Temperature-Controlling Equipment,capable of main-taining the test temperature to63°C.If ambient laboratory conditions are employed the same degree of control is required.
6.Test Specimen
6.1Make specimens that conform to the form and dimen-sions shown in Fig. 1.It is recommended that
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the test specimens be cut from the test panel depicted in Fig.2,but individual specimens may be prepared if preferred.The rec-ommended metal substrate is Alloy2024-T3aluminum,1.56 0.1mm.A surface treatment such as Method A of Practice D2651is recommended for the aluminum.If a metal substrate other than aluminum is employed,then one of the other surface preparations in Practice D2651is suggested.The recom-mended length of overlap is12.560.2mm.The thickness of the plastic in the metal/adhesive/plastic/adhesive/metal sand-wich configuration may vary depending on the type and manufacturer but thinfilms of0.35mm or less are recom-mended.An upper limit of1.560.1mm plastic thickness is suggested.
6.2The surface preparation ud on the adherend depends on the subject plastic adherend.Methods such as tho recom-mended in Practice D2093rve as a uful guide.
6.3Apply the adhesive in accordance with the manufactur-er’s recommendations.Choo the adhesive such that the cure temperature does not adverly affect the mechanical proper-ties of the adherend.
6.4Cut test specimens from the bonded panels pictured in Fig.2.Cutting the specimens must be accomplished without overheating or otherwi physically damaging the adherend or bonded interface.Individual test specimens may also be prepared if desired.
if only 电影7.Proceduretail是什么意思英语
7.1Condition the test specimens for definite periods of time under specified conditions before testing if desired.After conditioning,it is recommended that all specimens be stabi-lized in the test environment for1h before testing.
7.2Place the test specimens in the grips of the testing machine so that the applied load coincides with the long axis
of FIG.1Form A—Dimensions of Test
Specimen参数英文
the specimen.Load the specimen to failure at a rate of 80to
become是什么意思100kg/cm 2of shear area per minute.
clo是什么意思N OTE 2—The thickness of the plastic inrt ud will influence the joint
strengths obtained in this test due to the added offt.Thermal stress
introduced in the joint by elevated temperatures bonding dissimilar
materials will also offt ultimate joint strength.Direct comparison of
results is possible only for the same thickness and composition of inrt so
as to minimize differences resulting from offt or thermal stress.
8.Calculations
illa8.1Calculate the bond area to the nearest 0.05cm 2.Record
both load at failure and type of failure (percentage cohesive
and apparent failure in adhesion).Calculate failing stress as
megapascals of shear area.
9.Report
9.1Report the following:
9.1.1Complete identification of the adhesive tested,includ-
ing type,source,date manufactured,manufacturer’s code
number,form,etc.
9.1.2Complete identification of the metal ud,its thick-
ness,and method of cleaning and preparing its surface prior to
bonding.
9.1.3Complete identification of the plastic ud,its thick-
ness,and the method of cleaning and preparing its surface prior
to bonding.9.1.4Method of adhesive application (brush,spray,roller coat,tape,etc.).9.1.5Ambient conditions at time of bonding (temperature,humidity,etc.).9.1.6Length of overlap ud.9.1.7Conditioning of joint prior to testing.9.1.8Maximum,minimum,and average values of the fail-ing load.9.1.9Number of specimens tested.9.1.10Type of failure.This should include estimated per-centages of cohesive failure in the adhesive unbonded area,apparent failure in adhesion,and failure in the adherend.9.1.11Test temperature employed.9.1.12The average thickness of adhesive layer after forma-tion of the joint shall be reported within 0.01mm.The method of obtaining the thickness of the adhesive layer shall be described including procedure,location of measurements and range of measurements.10.Precision and Bias 10.1A precision and bias statement does not exist for this test method becau resources necessary for round robin testing have not been
forthcoming.
FIG.2Standard Test
Panel
11.Keywords
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11.1adhesive bond;lap-shear;sandwich joint;shear;ten-
sion
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