Webinar - Fracture mechanics testing and engineering critical assessment

Watch this webinar and find out what defects like inherent flaws or in-service cracks mean for your structure in terms of design, validation, inspection and lifetime.
We will introduce you to what fracture mechanics testing is and how it can be used in the design and operation phases of your structures and products. With engineering critical assessment we will show you how to optimise the output and value of your fracture mechanics testing programs to push the envelope in your design and in your operational conditions.
The webinar will give you insight into how fracture mechanics testing and its results can be used during the design and verification phase as a complementary tool to design standards. Within the field of integrity management fracture mechanics testing can be used to determine if an in-service crack is at a point and must be repaired or for establishment of an inspection plan.

[@husairyharon3755]

Good One.

[@IoldxmanI]

Could you more detail explain your position "if we want to test for ductile fracture we can use a thinner materials but if we want to test for a brittle fracture then we need to go to thicker materials or thicker test specimen"

[@forcetechnology]

Hi Vladimir.
Thank you for your question.
We assume that you are familiar with plane stress and plane strain conditions.
We know that thinner steels can show brittle fracture, especially in the presence of stress concentrations, or when exposed to low temperatures.
So the intention was not to write that we cannot test for brittle fracture on thin specimens.
The intention was rather to explain that specimen thickness (in steels) can influence test results, so thickness need to be considered.
It also has an influence on the cost and the schedule.
We do hope this answers your question.

[@haozhezhang5287]

@@forcetechnology Thank you for your explanation. Since thinner steels show a brittle fracture, why do we still use a thin one for the test? And for brittle material, for example, ceramic, what the influence of using a thinner specimen for the test (decrease/increase the toughness and why)?

[@forcetechnology]

@@haozhezhang5287 Thank you for your question.
Just to clarify: thinner specimens are prone to ductile fracture. When thickness or specimen size is large enough, plane strain conditions become dominant and the plastic zone near the crack tip becomes very small. In this case you will be able to obtain brittle fracture. Lower temperature makes steel more brittle, as mentioned in the previous answer.
It is usually a limitation in the available material that limits the size of the test specimens. For plate materials, the test specimens might be thinner than required for obtaining a brittle fracture in the test (Valid KIC) due to plate thickness. In this case, you test the specimens that are possible to manufacture from the available material, and obtain a fracture toughness value that is valid for this material and thickness.
If you obtain brittle fracture and all clauses in the standard are fulfilled, you get a geometry independent fracture toughness which is valid through all thicknesses. In general, a fracture toughness obtained in plane strain conditions is lower than a fracture toughness obtained in plane stress conditions.
We have not tested ceramic materials and cannot provide an answer on how they behave at different material thicknesses.

[@haozhezhang5287]

@@forcetechnology Thank you so much for the very detailed explaination! You have completely answered my question.