Hi,everybody!
assumption in the following(In Ceasar using B31.3 Code):

L1 = W + P + T + D (OPE)

L2 = W + P (SUS)

L3 = L1 - L2(EXP) ,and combination method:algebraic

we always use L3 to check the themal expansion stress, but take little attention to the combination method.

here,wo use the algebraic method In order to be consistent with the B31.3 Code.

but My question is that why can not we use the scalar method for L3 combination method.
is that the bending moment using the algebraic combination method is always greater than using the scalar method in mathematics ? the equation is :
(M1x*M1x + M1y*M1y + M1z*M1z)(M2x*M1x + M2y*M2y + M2z*M2z)>=
(M1x*M2x + M1y*M2Y + M1z*M2z)(M1x*M2x + M1y*M2Y + M1z*M2z)

can anyone tell me the real consideration in physics?