Die Einrichtung einer Prozessüberwachung beim mechanischen Fügen ist zeit- und kostenintensiv. Vorgestellt wird ein Vorgehen auf Basis einer numerischen Simulation unter Berücksichtigung stochastischer Einflüsse, welche die Einrichtung signifikant beschleunigen kann. Gleichzeitig wird eine Prognose über die Tragverhaltenseigenschaften bei variierenden Prozessparametern abgegeben. Die Erläuterungen erfolgen an einem klassischen mechanischen Verbindungselement.   A quality assurance system using process curves of mechanical joining procedures is time-consuming and costly. This paper presents an approach based on numerical simulation considering stochastic effects to significantly speed up the appliance of such monitoring areas. At the same time, a forecast of the resulting bearing behavior is produced. The generally applicable procedure is exemplified on lockbolts as a classical mechanical joining element.

Die Einrichtung einer Prozessüberwachung beim mechanischen Fügen ist zeit- und kostenintensiv. Vorgestellt wird ein Vorgehen auf Basis einer numerischen Simulation unter Berücksichtigung stochastischer Einflüsse, welche die Einrichtung signifikant beschleunigen kann. Gleichzeitig wird eine Prognose über die Tragverhaltenseigenschaften bei variierenden Prozessparametern abgegeben. Die Erläuterungen erfolgen an einem klassischen mechanischen Verbindungselement.   A quality assurance system using process curves of mechanical joining procedures is time-consuming and costly. This paper presents an approach based on numerical simulation considering stochastic effects to significantly speed up the appliance of such monitoring areas. At the same time, a forecast of the resulting bearing behavior is produced. The generally applicable procedure is exemplified on lockbolts as a classical mechanical joining element.

Background Endoscopic and laparoscopic electrosurgical devices (ED) are of great importance in modern medicine but can cause adverse events such as tissue injuries and burns from residual heat. While laparoscopic tools are well investigated, detailed insights about the temperature profile of endoscopic knives are lacking. Our aim is to investigate the temperature and the residual heat of laparoscopic and endoscopic monopolar instruments to increase the safety in handling ED. Methods An infrared camera was used to measure the temperature of laparoscopic and endoscopic instruments during energy application and to determine the cooling time to below 50 °C at a porcine stomach. Different power levels and cutting intervals were studied to investigate their impact on the temperature profile. Results During activation, the laparoscopic hook exceeded 120 °C regularly for an up to 10 mm shaft length. With regards to endoknives, only the Dual Tip Knife showed a shaft temperature of above 50 °C. The residual heat of the laparoscopic hook remained above 50 °C for at least 15 s after activation. Endoknives cooled to below 50 °C in 4 s. A higher power level and longer cutting duration significantly increased the shaft temperature and prolonged the cooling time (p < 0.001). Conclusion Residual heat and maximum temperature during energy application depend strongly on the chosen effect and cutting duration. To avoid potential injuries, the user should not touch any tissue with the laparoscopic hook for at least 15 s and with the endoknives for at least 4 s after energy application. As the shaft also heats up to over 120 °C, the user should be careful to avoid tissue contact during activation with the shaft. These results should be strongly considered for safety reasons when handling monopolar ED.

The mechanics of medical endoscopes have not fundamentally changed over the last 40 years. Most endoscopes are manually operated through Bowden cables to control the head of the device, which is known to have major limitations. We propose a shape memory alloy actuated setup to enable computer-aided control. Before a complex manufacturing of porotypes is established, the design needs to be evaluated for feasibility. In this work, an efficient design approach is highlighted, where the thermal properties for an asymmetric cross-section of the endoscope is modeled with finite elements in the transient electro-thermo-mechanical domain and the results are then transferred to a network model to efficiently evaluate operation procedures. With the proposed model approach, a fast but detailed description is established which focuses on the optimization of dimensional and material parameters and models efficiently the impact of complex dynamic operating regimes.