Nondestructive Evaluation of Spot Welds Using Acoustic and Thermographic Imaging Techniques

Thermography in manufacturing: nondestructive evaluation of ultrasonic spot welds of automotive battery pack

“…Traditionally, thermography-based NDE have been considered as having insufficient resolution and reliability [1,2]. Present work corrects this perception.…”

“…Heat propagation in the sample is governed by the parabolic partial differential equation and, together with initial and boundary conditions, represents an initial boundary value problem for temperature distribution T(x, t). Denoting thermal diffusivity, thermal conductivity and density as a, k,  , duration and intensity of thermal pulse as t0 and q and the part of the surface illuminated by flash as 1  and not illuminated as 2  , we obtained the following formulation:…”

“…Such techniques include acoustic microscopy, shearography and X-ray radiometry [1,2]. However, the NDE technique, capable of providing reliable results in production is still lacking.…”

Simulation and Evaluation of Pulsed Phase Thermography for the Quality Control of Resistance Spot Welds

“…Several investigations describe the ability of thermal techniques to characterize spot welds [1,2,3], but a successful adaptation to production line requirements has not been realized yet. To provide thermographic equipment capable of replacing recent cost intensive destructive testing procedures, questions concerning the evaluation criteria, adequate stimulation methods and sufficiently robust data processing techniques have to be clarified more comprehensively.…”

“…To provide thermographic equipment capable of replacing recent cost intensive destructive testing procedures, questions concerning the evaluation criteria, adequate stimulation methods and sufficiently robust data processing techniques have to be clarified more comprehensively. Some prior publications indicate for example the feasibility to identify incomplete or fragile welds (characterized by solid but weak contact) [1,2] and mention the possibility to estimate spot weld sizes [3]. In most cases, however, they are restricted to specific conditions (e. g. uncoated plates, black painted surfaces, through transmission configuration).…”