The Research On The Method Of Testing The Cold-formed Thin-walled Steel's Remnant Stress And The Member's Whole Stability Of Axially Loaded Compression With Remnant Stress

The remnant stress of steel-structure is produced for the plastic deformation which was brought in the member's producing process, it's first balanced itself in the structure before the outside force is loaded. When the outside force is loaded, the stress brought by the load and the remnant stress spliced with each other, so the structure's firmness and stability are depressed. In order to measure the remnant stress, we should apart or destroy the member, release the stress, and then measure it. The traditional machine-cut method (or handwork cutting) is only the same with hot roll profiled bar, not the cold-firmed thin-wall steel.Weng CC, Pekoz T put forward the assumption of using electro-chemical corrosion method to measure the remnant stress of the cold-formed thin-wall steel. The electro-chemical corrosion makes use of steel's characteristics that is easy to be eroded, essentially gets over the defects of machine or handwork cutting, and solves the measure-problem in principle. Weng CC, Pekoz T tested the out-rolled cold-formed steel's remnant stress (2.5mm in thickness), but didn't promulgate the craftwork and correlative materials prescription of the method. We developed a lot of work aiming at measuring cold-formed thin-wall steel in electro-chemical corrosion method, which including the craftwork,the experiment equipment,the description of the erode liquid and the choice of the antiseptic materials of the method and so on, and tested the cold-formed rolled angle iron(2.5mm in thickness), and got some phased fruits.In this paper, we continue studying in depth how to test the cold-firmed thin-wall steel's remnant stress by electro-chemical corrosion method, and get some technical innovations, then the rate of the test is advanced and the outcome of the test is more accurate:First, we improve the tester. According to father's experience, we know the electrical source is very important to the test, after the compare of several kinds of electrical source, in the test, we use the WYJ-20000 series direct current steady-pressure and steady-electricity electrical source by compare, whose work state is relatively steady, and the erode-speed is quickened. Second, we confect new-style antiseptic material with excellent antiseptic capability. On the position of the cutting-bar, we use double deck antisepsis, this is a innovation at the father's basic:On the inner layer, we use a kind of self-mixed elastic silica gel. The silica gel is elastic and can felt with the member close, so when the cutting bar's stress was released, the strain piece wouldn't fall off and be disabled.On the outer layer, we use a kind of self-mixed polystyrene glue. This glue can be dry and hard in a very short time, so the seedtime of the test is shortened.The glue confect by us has wonderfully antisepsis capability, and it can well adapt the...