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Definition: Special tests are individually developed or adapted testing methods for clarifying specific technical questions that are not sufficiently covered by standardised normative tests. They frequently combine several analysis and testing methods. The aim is a robust, problem-oriented assessment.

Practical relevance: Fields of application include complex failure cases, novel materials, atypical loading scenarios or special regulatory requirements. Special tests can comprise modified mechanical tests, combined environmental stresses or special specimen geometries. A traceable documentation of the test set-up, boundary conditions and measurement uncertainty is essential.

Decision-making perspectives:

• Technical decision-makers: Clarification of specific failure mechanisms or suitability verifications beyond standardised tests.
• Purchasing/project management: Definition of individual acceptance criteria for innovative products.
• Science: Development of validatable test designs and comparison with reference methods.
• Insurance/law: Court-proof documentation in exceptional failure or dispute cases.

Typical testing or verification methods: Combined climatic and load tests, modified fatigue tests, special corrosion or media tests.

FAQ:

• When are special tests required?
• When normative standard tests do not sufficiently represent the specific technical question.

Definition: Spectral analysis is an analytical method for determining the chemical composition of a material on the basis of characteristic emission or absorption spectra. It uses the element-specific spectral lines for qualitative and quantitative analysis. In materials engineering, it is used to determine alloying and trace elements.

Practical relevance: Typical methods are optical emission spectroscopy (OES), X-ray fluorescence analysis (XRF) or ICP-OES. Detection limits and accuracy depend on the method and the sample preparation. Applications include incoming goods inspections, PMI testing and failure analyses. Results are compared with normative material specifications.

Decision-making perspectives:

• Technical decision-makers: Ensuring the correct material composition in safety-relevant components.
• Purchasing/project management: Verification of supplier assurances in accordance with material standards.
• Science: Validation of analytical accuracy and comparison of different spectrometry methods.
• Insurance/law: Documented proof of material deviations in liability cases.

Typical testing or verification methods: OES, XRF, ICP-OES, comparison with reference materials.

FAQ:

• What is the difference between OES and XRF?
• OES uses emission lines after spark excitation, whereas XRF measures fluorescent X-rays without removing material.