In this paper, we present a unified decommitment method to solve the unit commitment problem. This method starts with a solution having all available units online at all hours in the planning horizon and determines an optimal strategy for decommitting units one at a time. We show that the proposed method may be viewed as an approximate implementation of the Lagrangian relaxation approach and that the number of iterations is bounded by the number of units. Numerical tests suggest that the proposed method is a reliable, efficient, and robust approach for solving the unit commitment problem.

Êèòàéñêèé ñåëüñêîõîçÿéñòâåííûé óíèâåðñèòåò, Ïåêèí, Êèòàé Ñ ïîìîùüþ ïðîãðàììíîãî êîìïëåêñà ABAQUS âûïîëíåíî êîíå÷íîýëåìåíòíîå ìîäåëèðîâàíèå êîìáèíèðîâàííûõ áîëòîâûõ è ñâàðíûõ ñîåäèíåíèé ñ öåëüþ èçó÷åíèÿ ìåõàíèçìîâ ðàçðóøåíèÿ è íåñóùåé ñïîñîáíîñòè. Ïðîàíàëèçèðîâàí âêëàä ñâàðíûõ øâîâ è áîëòîâûõ ñîåäèíåíèé â îáùóþ íåñóùóþ ñïîñîáíîñòü êîíñòðóêöèè. Ìåõàíèçìû ðàçðóøåíèÿ è íåñóùàÿ ñïîñîáíîñòü îáðàçöîâ ñ ðàçëè÷íûìè ðàçìåðàìè ñâàðíûõ øâîâ îöåíèâàëèñü ïî äàííûì ÷èñëåííûõ ýêñïåðèìåíòîâ, â õîäå êîòîðûõ ðàññ÷èòûâàëèñü ïðî÷íîñòíûå õàðàêòåðèñòèêè áîëòîâ ñ ïîñòîÿííûì ñå÷åíèåì è îáðàçöîâ ñ ðàçëè÷íûìè ðàçìåðàìè ñâàðíûõ øâîâ â êîìáèíèðîâàííîì ñîåäèíåíèè. Ïðè ýòîì ïðî÷íîñòü ñâàðíûõ øâîâ áûëà âûøå, ÷åì áîëòîâ. Ïî ìåðå óâåëè÷åíèÿ ñîîòíîøåíèÿ ïðî÷íîñòè ñâàðíûõ øâîâ è áîëòîâ âêëàä ïîñëåäíèõ â íåñóùóþ ñïîñîáíîñòü êîìáèíèðîâàííîãî ñîåäèíåíèÿ ñíèaeàåòñÿ äî íóëÿ ïî äîñòèaeåíèè ýòèì ñîîòíîøåíèåì óðîâíÿ 2,0.Êëþ÷åâûå ñëîâà: êîìáèíèðîâàííîå ñîåäèíåíèå, çàòÿaeíîé âûñîêîïðî÷íûé áîëò, ñâàðíîé øîâ, êîíå÷íîýëåìåíòíûé ðàñ÷åò.Introduction. The combined connection with bolts and welds is a common connection form that adopts the friction type high-bearing capacity bolts and fillet welds in one joint and the bolts and welds work together to bear the shear load. In this paper, it is widely considered that the combined connection with bolts and welds have the advantages of the friction-type high bearing capacity bolted joints (hereafter referred to as the bolt joint) and the side-weld joint (hereafter referred to as the weld joint). The research on the mechanical behavior of the combined connection with bolts and welds is complicated because the bearing capacity of the combined connection with bolts and welds is validated not equal to the sum of the weld joints' and the bolt joints' bearing capacity, respectively, by earlier studies. The load sharing of the bolts and welds in the combined connection is related to the mechanics mechanism of the bolts and the welds. Many scholars have analyzed shear bearing capacity and the work behavior of the combined connection with bolts and welds. Some regulations and design formulas of the combined connection with the bolts and welds have been established in some standards. The design requirement is illustrated in [1]. According to the procedures, bearing capacity difference between high bearing capacity bolts and welds should be less than 3 times. Meanwhile, the formula to calculate the shear bearing capacity of the combined connection joints with friction-type bolts and side welds was given in [1]. Moreover,in [2], it is required that standard hole or slot should be perpendicular to the stress direction under the combined connection with bolts and welds.