A weir-type diaphragm valve includes a valve body with a fluid channel and a weir with a weir sealing portion; and a diaphragm with diaphragm portions, including a diaphragm weir sealing portion at the weir that responds to one force and travel against the weir sealing portion to close the valve and stop fluid flow through the fluid channel, and responds to a second force and travel away from the weir sealing portion to open the valve and allow fluid through the fluid channel, a center flexing portion off the weir that experiences convex and concave flexing extremes when the valve is closed/opened, and an outer sealing portion fully constrained between components, one of which includes the valve body, when the valve is closed/opened. The diaphragm portions have different characteristics based on different material stresses associated with different functionality that each portion performs when the valve is closed/opened.