Lastspektren

Lastspektren are representations of external loads that act on a structure or system, expressed as a function of time or as a spectrum over frequency. The time-domain form describes load histories, while the frequency-domain form expresses how load energy is distributed across frequencies. They are used to characterize the excitation a component must withstand during its service life and to guide design and analysis.

They can be obtained from field measurements, laboratory tests, or published standards, and may also be generated by stylized models for design studies. Examples include wind and traffic load histories in civil engineering, seismic records for earthquake engineering, or electrical load profiles for reliability testing. In many applications, both time-domain and frequency-domain representations are considered to capture different aspects of the loading process.

In analysis, Lastspektren are used to estimate dynamic response, natural-frequency behavior, and fatigue life. A time-domain load history can be applied directly in transient simulations, while a frequency-domain spectrum permits linear response calculations and modal analysis. For fatigue assessment, spectra are converted into stress ranges through spectral methods, often combined with rainflow counting and cumulative damage models such as Miner’s rule.

Applications are widespread across fields such as civil, mechanical, aerospace, and electrical engineering. In civil engineering, wind and traffic spectra inform bridge and building design; in mechanical systems, vibration and shock spectra guide component durability; in power systems, load spectra aid reliability planning and stress testing of equipment. Limitations include assumptions of stationarity, linearity, and independence of loading channels; complex, non-stationary, or highly non-Gaussian loads may require advanced, multi-axial or time-varying spectral techniques.