Download Citation on ResearchGate | On Jan 1, , Jan W. Gooch and others published ASTM D }. Standard. Standard number, ASTM-D ; ASTM-D Title, Standard Test Method for Flexural Fatigue of Plastics by Constant. Find the most up-to-date version of ASTM D at Engineering
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Modification of ASTM D Type Fatigue Testing Apparatus for Chemical Fatigue
If a molded component or material is subjected to a repetitive load in a practical-usage environment, failure ie, cracking will take place after a certain number of cycles astk a load much lower than its static yield stress. This phenomenon is referred to as material fatigue; and the corresponding failure, as fatigue failure.
Surfaces resulting from fatigue failure can be identified by the clam-shell marking which is distinctive to this phenomenon. Shear stress is the main type of stress that directly affects failure, and as a result of 6d71, sliding occurs between sections of the material; furthermore, disintegration then occurs when countless minute fracture zones are formed.
Testing standards and conditions Standard: The test piece is to be as shown on the right. Toyo Seiki model B max.
Astm d671 pdf
When the unbalanced mass is rotated by the motor, centrifugal force is exerted on the axis of rotation. Horizontal oscillation as a result of this centrifugal force is eliminated through the action of a leaf spring, thus ensuring that zstm test piece is exposed only to an oscillating load in the vertical direction.
The stress being exerted on the test piece or the applied load can be varied by changing the rotation radius of the aetm mass.
Although this tester generates a constant stress, the corresponding amplitude is not fixed as this varies in accordance with the elasticity of the test piece. During testing, the number of load repetitions or oscillations until fatigue failure occurs in the test piece is measured for each stress or loadand a graph is created with stress on the y axis and the number of repetitions on the x axis. Customers are requested to asrm determine the suitability of our materials for their products.
We atsm request that sufficient attention also be paid to laws, regulations, and industrial rights. Fatigue Failure If a molded component or material atsm subjected to a repetitive load in a practical-usage environment, failure ie, cracking will take place after a certain number of cycles at a load much lower than its static yield stress.
As a result of this mechanism, a clam shell pattern is generated. Fatigue durability is dependent on the corresponding stress value, and for this reason, the occurring stress should be lowered by reducing the load or by implementing design factors which distribute this load.
In order to prevent the generation of cracks which constitute the start point for fatigue failure: Contact with oils, detergents, and any other chemical agents that attack plastic has a significant detrimental effect on fatigue durability, and this should therefore be avoided.
Welded sections readily give rise to the start of fatigue failure, and for this reason, measures should be implemented to prevent repetitive loading at such sections. Plastics with superior fatigue durability should be used.
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