stresses 4) __________.

4. In the OXYZ Cartesian coordinates, a stress state of a point is(1) Draw the stress unit cube with the stresses labeled on X, Y and Z planes; (6 points)(2) One of the X, Y and Z planes is a principal plane. Which is the principal plane, and what is the principal stress on it？ (4 points) (3) Find the characteristic equation of the stress state, and solve the other 2 principal stresses at this point; (6 points) (4) Calculate the maximum shear stress and the mean stress at this point. (4 points)

如下式所示：式中(4)为()

A、体积力项(body force)

B、压力项(pressure force)

C、惯性力项(Inertia force)

D、粘性力项(viscous stresses)

ameter of the first shaft is one half of that of the second one. The ratio of the maximum shear stresses in these two shafts should be

A、2:1

B、4:1

C、8:1

D、16:1

A simply supported beam is subjected to a linearly varying distributed loadwith maximum intensityat B. The beam has a length L = 4 m and rectangular cross section with a width of 200 mm and height of 300 mm. Determine the maximum permissible value for the maximum intensity,, if the allowable normal stresses in tension and compression are 120 MPa.

1. explain the following terminologies: (4 points per question, 40 points in total) (1) plastic forming (2) principal stresses (3) yielding (4) Tresca’s yield criterion (5) superplasticity (6) recrystallization temperature (7) true strain (8) The generalized Hooke’s law (9) Incremental theories (10) Strain energy per unit volume

d to fluctuating _____.

A.bending stresses

B.torsion stresses

C.shear stresses

D.All of the above

ial issue following the earthquake. (1) In fact, however, trauma is only a small part of a wide array of psychosocial issues that ought to be addressed. For many earthquake survivors, the main issue is not traumatic memories of the earthquake but stresses associated with their current living situation. These stresses include the lack of safety and security, the loss of livelihood, lack of appropriate shelter, changes in family relations, threats of and exposure to gender-based violence, substance abuse, and uncertainties about the future. Because these stresses are holistic, they require comprehensive support that goes beyond trauma counseling. (2) Inherently, the support needed is social rather than psychological and includes such things as normalizing life by reestablishing daily activities such as working for parents and education for children, protection from rape and other forms of gender-based violence, the development of livelihood, and the strengthening of community networks of social support.

However it is not just the kind of support—social or psychological—that makes a difference. Across humanitarian sectors, the way in which relief is provided has a strong impact on psychosocial well-being. A common error is to view earthquake survivors as passive victims who need to be taken care of or healed by outsiders. (3) In the present emergency, the most effective means of providing psychosocial support is through a process of community mobilization and empowerment wherein communities make their own decisions and develop their own systems of protection, care, and support for survivors. When communities make choices about how to move forward, they reestablish a sense of control that is a powerful antidote to feelings of being overwhelmed. (4) As they engage in collective planning and action, they gain a sense of hope for the future and move out of the victim's role they too often are cast into.

(5) Psychosocial support is not mainly something done to or for people by psychologists or psychiatrists but a process of local people activating their own social support for their collective well-being and positive future. Taking heed of this key point, the emphasis in earthquake response should be on social interventions that empower local people. At best, trauma counseling is a very small part of the much wider array of support that will help victims get on with their lives.

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