The maximum hydrostatic tension stress in the hydrided zircaloy-4 usually occurs in the region of the hydride-matrix interface, which is irrelevant to the loading path.

Higher speed, smaller feed and larger tool tip radius help to decrease hydrostatic tension in machined layers, which improves the surface integrity of the machined workpiece and eliminate residual stresses.

A series of hydrostatic tension tests are performed at room temperature to provide new insight into the progressive deterioration of the bulk stiffness.

Stress softening of elastomers in hydrostatic tension

In thick and thin joints, macroscopic plastic instability and hydrostatic tension respectively are the major causes of void growth and ductile fracture.

The experimental results are combined with the associated flow rule to show that the yield surface is asymmetric with respect to hydrostatic tension and compression.

The average hydrostatic tension and pressure stresses in soft and hard phases developed during monotonic loading make the soft phase harden and hard phase soften.

The initiation of mixed-mode crack is usually determined by one of se-veral mixed-mode fracture initiation criteria. During the past two decades, the[G]_(max) criterion, [S]_(min) criterion and [σ_θ]_(max) criterion were presented one afteranother. It has been found that the [G]_(max) criterion, [S]_(min) criterion and [σ_θ]_(max)criterion are appropriate for the brittle fracture and penetrated crack. In 1986,Chen applied these criteria to the surface crack problems and found that thereare some defects in these...

The initiation of mixed-mode crack is usually determined by one of se-veral mixed-mode fracture initiation criteria. During the past two decades, the[G]_(max) criterion, [S]_(min) criterion and [σ_θ]_(max) criterion were presented one afteranother. It has been found that the [G]_(max) criterion, [S]_(min) criterion and [σ_θ]_(max)criterion are appropriate for the brittle fracture and penetrated crack. In 1986,Chen applied these criteria to the surface crack problems and found that thereare some defects in these criteria [1]. These defects are chiefly the followingones: (1) All these three criteria did not consider the effect of the small-scaleyielding at crack front. (2) They all considered just one factor of crack initiation and neglectedother complicated factors of crack initiation. To eliminate these defects, according to the micro-theory of fracture me-chanics, the appearance of fracture section and some known results, three frac-ture initiation criteria are proposed in this paper by using respectively thedilational strain energy density on the elastic-plastic boundary at crack front,the hydrostatic tension stress on the constant strain energy density plane aro-und crack-tip, and the plastic area size near crack-tip as the parameters underthe small-scale yielding condition. To test the three criteria proposed in this paper, the surface inclined cra-ck, which is most harmful in practice, is studied. In Ref. [1], because of somedifficulties, the calculations are very limited and only concerned with theoutside and deepest points of surface crack. But the interior points are alsovery important. So in this paper the calculations of some interior points alongthe surface crack front are done. By using the three criteria, the general ma-thematical expressions of the initiation angles (α_i~*、θ_i~*) and the critieal loadsQ_i~* at the arbitrary points of the semi-elliptical surface inclined crack aregiven. The initiation angles (α_i~*、θ_i~*) and the critical loads Q_i~* of LC4CS finitewidth plate with a semi-elliptical surface inclined crack under uniform tensionare calculated when the location angle φ is equal to 0°, 15°, 30°, 45°, 60°,75° and 90° and the inclined angle β is equal to 15°, 30°, 45°, 60°, 75° and90° respectively. The curves θ_i~*-φ,θ_i~*-γ, α~(1/2)Q_i~*/WBK_(Ie)-φ and α~(1/2)Q_i~*/WBK_(Ie)-β are plotted. The calculated results are discussed and compared with the results in Ref. [1] which are from the [G]_(max) criterion, [S]_(min) criterion,[σ_θ]_(max) criterion and experiments. All results show that the values from thenew three criteria are better than those from the old three criteria and agreewith ASTM standard completely [18]. So the authors conclude that the newthree criteria proposed in this paper are more practicable than the [G]_(max) cri-terion, [S]_(min) criterion and [σ_θ]_(max) criterion.

Hydrogen induced cracking of 0.3% C,1% Cr, 1% Mn, 1% Si highstrength steel has been studied under simple mode Ⅰ, mode Ⅱ and (Ⅰ+Ⅱ) mixedmode loading conditions. After being hydrogen-charged in 1N H_2SO_4 solution, thematerial behaved hydrogen embrittlement in all the cases studied. The results showthat simple mode Ⅰ or mode Ⅱ loading are more susceptible to hydrogen embrittle-ment than (Ⅰ+Ⅱ) mixed mode. For explaining the experimental results, the effectsof hydrostatic tension as well as plastic deformation...

Hydrogen induced cracking of 0.3% C,1% Cr, 1% Mn, 1% Si highstrength steel has been studied under simple mode Ⅰ, mode Ⅱ and (Ⅰ+Ⅱ) mixedmode loading conditions. After being hydrogen-charged in 1N H_2SO_4 solution, thematerial behaved hydrogen embrittlement in all the cases studied. The results showthat simple mode Ⅰ or mode Ⅱ loading are more susceptible to hydrogen embrittle-ment than (Ⅰ+Ⅱ) mixed mode. For explaining the experimental results, the effectsof hydrostatic tension as well as plastic deformation ahead of crack tip has beendiscussed.

The Gurson's constitutive model is investigated. Based on Gurson's constitutive model and large elastic\|plastic deformation, necking behavior of a round tensile bar is analyzed numerically. The void nucleation, growth, hydrostatic tension and material softening are discussed in the neck region. From the numerical results, it indicates that the developments of void and damage mechanism of material are revealed.