termomekanik

Termomekanik is an interdisciplinary field that studies the interaction between thermal and mechanical phenomena in materials and structures. It covers the coupling of heat transfer, temperature-dependent properties, and mechanical responses, including elasticity, plasticity, viscoelasticity, and phase transformations.

Core concepts include thermal expansion, thermal stresses from temperature gradients, and the temperature dependence of stiffness, strength, and damping. Constitutive models relate stress, strain, and temperature, ranging from linear thermoelasticity to nonlinear, rate-dependent thermo-viscoplastic formulations.

Governing equations couple mechanical and thermal fields. The balance of linear momentum is div(sigma) + b = rho a. The energy balance is rho c dT/dt = div(k grad T) + q + sigma : dot(epsilon). Thermal strain is often represented as epsilon_th = alpha (T - T_ref) I, where alpha is the coefficient of thermal expansion.

Modeling approaches include linear thermoelasticity for small deformations, nonlinear thermoelastic and thermo-viscoplastic theories for larger strains and rate effects. Numerical methods, especially finite element analysis, are widely used to solve coupled heat transfer and mechanical problems in engineering designs.

Applications span electronics packaging, where thermal cycling induces stresses in dies and solder joints; turbine and engine components at elevated temperatures; automotive and aerospace structures subjected to temperature changes; and additive manufacturing, where thermal gradients create residual stresses and distortions.

Historically, termomekanik grew from thermoelasticity and heat transfer theory and has expanded with composite materials, micro-scale systems, and energy technologies. It remains essential for predicting reliability, safety, and performance under combined thermal and mechanical loading.