Residual Stress Distribution Model Research Articles

Experimental study on residual stresses in cold rolled austenitic stainless steel hollow sections

This paper focuses on the residual stresses in cold rolled austenitic stainless steel hollow sections. A series of residual stresses tests were carried out. Eight cross sections were tested, including four rectangular hollow sections and four circular hollow sections. The fabrication route of the test specimens was measured and introduced. Sectioning method modified with T rosettes strain gauges was used to reveal the residual stresses, including the longitudinal and transverse bending and membrane residual stresses. Totally, residual stresses of 160 points were recorded. Plane stress condition assumption was used in processing the residual strains. Test results indicate that the dominated residual stress was the longitudinal bending residual stress for RHS, and longitudinal and transverse bending residual stress for CHS. The magnitudes of all the other types of residual stress were less than 50 MPa. Residual stress distribution models were proposed based on the test data, and compared with test data available in literatures. Comparisons show the residual stresses in cold formed section highly depend on manufacturing processes and material types.

A Simplified Model for the Effect of Weld-Induced Residual Stresses on the Axial Ultimate Strength of Stiffened Plates

The present work investigates the compressive axial ultimate strength of fillet-welded steel-plated ship structures subjected to uniaxial compression, in which the residual stresses in the welded plates are calculated by a thermo-elasto-plastic finite element analysis that is used to fit an idealized model of residual stress distribution. The numerical results of ultimate strength based on the simplified model of residual stress show good agreement with those of various methods including the International Association of Classification Societies (IACS) Common Structural Rules (CSR), leading to the conclusion that the simplified model can be effectively used to represent the distribution of residual stresses in steel-plated structures in a wide range of engineering applications. It is concluded that the widths of the tension zones in the welded plates have a quasi-linear behavior with respect to the plate slenderness. The effect of residual stress on the axial strength of the stiffened plate is analyzed and discussed.

A Model of Surface Residual Stress Distribution of Cold Rolling Spline

Residual stress is an important parameter in the evaluation of the performance of a cold rolling spline surface. However, research on cold rolling spline is rare. To improve the surface property of a spline, an involute spline is selected as the object of this study. The contour method for determining cold roll-beating residual stress involves measuring the force spatial distribution, performing a statistical analysis of the experimental results, establishing the parameters for the tooth profile for different positions (dedendum, pitch, and addendum) of residual stress, and determining the effect of pressure on the relationship between stress and the depth of the cold roll-beating. A response surface method is used to establish the spline tooth profile of the dedendum, pitch, and addendum of the residual stress and different depths of the stress layer to obtain the parameters of a multiple regression model and perform a comparative analysis of the experimental and prediction results. Research indicates that the prediction results have high reliability. The establishment of this model has important guiding significance to control the residual stress in the cold roll-beating forming process, optimize the cold roll-beating processing parameters, and improve the surface properties of cold rolling spline.

Residual stresses in welded I-shaped sections fabricated from Q460GJ structural steel plates

A new type of high-performance structural steel named by GJ steel, has been widely used in many large scale structures like National Olympic Stadium (Birds Nest), new CCTV Headquarters and Canton Tower in China. However, previous studies on 460MPa GJ steel are very limited. In this study, the residual stresses on eight full scale I-shaped sections welded by flame-cut Q460GJ (“Q” means yield strength) steel plates including five doubly symmetric sections and three singly symmetric sections, were investigated by experimental tests. By using sectioning method, it was found that the deformation of curved strips was one part of circular curve. The results from the circular curve correction method are generally identical to the results from a new curve correction method named by “straightening measurement”. Then the residual stress distributions on Q460GJ welded I-shaped sections were obtained. It was concluded that residual stresses were related to sectional dimensions and flanges and webs were influenced with each other. Compared with the existing residual stress distribution models, the residual stresses on sectional flanges obtained in this study are much smaller, while no significant difference is found for sectional webs. It is also found that the flange tips are all under compression rather than tension, and the average value of the peak tensile residual stresses on flanges is only about 0.5fy. Finally, the residual stress levels at typical locations of I-shaped sections were summarized and suggested.

Investigation on surface residual stress distribution and evaluation of engineering ceramics in rotary ultrasonic grinding machining

Residual stress of engineering ceramics is one of surface integrity evaluation indexes affecting the parts’ strength properties. Rotary ultrasonic grinding machining is the most powerful machining method for engineering ceramics with better surface integrity. The residual stress field distribution is changed due to micro cracks which are inevitable in the process. A residual stress distribution model of machined surface micro crack tip has been established in the paper. And the experimental results enable us to obtain surface residual stress distribution of engineering ceramics in rotary ultrasonic grinding machining. Then, we propose an evaluation parameter called confidence stress tolerance to evaluate surface residual stress characteristic. Preliminary results indicate that surface residual stress distribution is in line with the normal distribution. Confidence stress tolerance is an effective parameter to improve the evaluation reliability. Furthermore, precision and affecting factors of confidence stress tolerance evaluation have also been investigated.

Residual stresses in high strength steel welded box sections

Induced residual tensile and compressive stresses generated by the fabrication process can cause premature buckling and reduce the ultimate axial strength of welded steel box sections subjected to compressive loads. Previous research pertaining to induced residual stresses has been restricted to box sections fabricated from mild steel and 460MPa high strength steel (HSS) using single pass welds or lightly welded sections. To date, very limited research has been undertaken to investigate the residual stresses in box sections fabricated from 690MPa HSS plates. This paper investigates the induced residual stress distributions in square welded sections fabricated from 690MPa HSS plates with single and multiple weld passes. The non-destructive neutron diffraction technique has been used to investigate the residual stresses in six test specimens: four specimens fabricated from 5mm HSS plates using single weld passes, and the other two specimens fabricated from 16mm HSS plates using six weld passes. Experimental results suggest that the 16mm thick heavily welded sections exhibited higher tensile residual stresses than the 5mm thick lightly welded sections, while the compressive residual stresses of the heavily welded sections were similar to the compressive residual stresses of the lightly welded sections. Considering the experimental results, a relationship between compressive residual stresses and width to thickness ratio of the specimens is formulated. In addition, a residual stress distribution model is proposed for lightly and heavily welded box sections.

Residual stress tests of welded Q690 high-strength steel box- and H-sections

Many studies on the experiment and simulation of residual stresses in mild carbon steel sections have been conducted. However, few investigations focus on Q690 high-strength steel sections. Because of the differences between high-strength steel and mild carbon steel in terms of stress–strain relationships and thermal properties of materials, it is necessary to investigate the residual stress in high-strength steel welded sections. In this study, three box- and H-sections fabricated from Q690 steel plates were employed for the measurement of residual stresses. The thickness of the sections with various dimensions was 16mm. This paper presents the magnitude and distribution of residual stresses in box- and H-sections made of Q690 steels. The simplified residual stress distribution models over box- and H-sections welded with Q690 steels are proposed. It is found that Q690 high-strength steel specimens possess lower ratios of residual compressive stress compared with that of Q460 steel specimens.

Residual stress distribution of large steel equal leg angles

The market offers new large steel angle profiles, the largest being L300/35. To check their buckling resistance, the investigation of the residual stress field is presented in this paper. Since the buckling behaviour of steel angles is significantly affected by the residual stresses, the stresses were measured on six hot rolled and two welded equal angles by sectioning method. The traditional sectioning method was improved by introducing the water jet cutting. The released deformations were measured by the strain gauges. On the basis of the statistical evaluation of the test results, the most appropriate residual stress distribution models were considered in the numerical analysis. The results of the geometrical and material nonlinear numerical analysis were equal angle buckling curves.

Experimental investigation and modeling on residual stress of welded steel circular tubes

To investigate the residual stress of welded steel circular tubes, an experimental program including 9 different sectional dimensions and different steel strength specimens were described in which sectioning method was employed. Based on large quantities of original test data, the residual stress distribution and the magnitudes of these different specimens were obtained, and the effects of the diameter to thickness ratio, the steel strength and hot galvanizing process as well as welding types were analysed. It was found that the residual stress distribution of high strength steel welded tubes was flatter than the ones of ordinary steel tubes, and galvanizing process decreased the maximum residual tensile stress. Finally, the residual stress distribution model for steel welded circular tube sections was proposed which showed good agreement with the test results. Meanwhile, the finite element verification was carried out which provided reference for the future FEA of column buckling of high strength steel circular tubes. The research results provide foundation for the future study on the column buckling of welded steel circular tubes.

Role of crack-tip residual stresses in stress corrosion behaviour of prestressing steel

This paper focuses on the role of crack-tip residual stresses of compressive nature, generated by fatigue loading, in stress corrosion cracking of pre-cracked samples of high strength pearlitic steel subjected to localized anodic dissolution and hydrogen assisted cracking. In both situations, compressive residual stresses improve the stress corrosion behaviour of the steel by delaying either the metal dissolution or the hydrogen entry, thus increasing the fracture load in an aggressive environment. The Rice model of residual stress distribution in the vicinity of a crack tip is used to explain these retardation effects by estimating the stress level and the plastic zone size.

Influence of applied tensile and compressive stress on large Barkhausen and Matteucci effects in amorphous wires

Investigation for establishing a residual stress distribution and domain model for amorphous magnetostrictive alloy wires were carried out. Therefore, voltage pulse generation due to the large Barkhausen jump (e p ) and the Matteucci effect (e p ') was studied as a function of tensile and compressive stress applied in the axial direction. The wires had a composition of Fe 77.5 Si 7.5 B 15 , made by the in-water quenching technique. The amplitude of the voltage pulses (e p and e p ') and domain nucleation field (H*), are found to decrease smoothly to zero at a critical compressive stress of 5 kg/mm2for the as-cast wires. A reduction in the critical stress to 3 kg/mm2is observed after altering the wire diameter from 125 to 95 µm by etching. Tensile stress above 20 kg/mm2was found to increase e p and H*. Squareness ratio (B r /B s ) is observed to be a continous increasing function of applied stress in the range from compressive, zero to tensile stress, being about 0.5 at zero stress. By reducing the diameter by 50% through etching, B r /B s is found to increase by about 20%. The observed results is indicating a gradually varying residual stress such that the core has a stress induced axial anisotropy and the outer layers has an anisotropy perpendicular to the axis, caused by positive magnetostriction.