Vibrational power flow analysis on combined plates partially covered layer of discontinuous material

Vibrational power flow on combined plates with a change in mass and stiffness or with viscoelastic damping layer used widely in engineering is studied. The expressions of flexural displacement and other physical quantities are obtained using Laplace transformation and transfer matrix approach, then influences of changes in mass and stiffness of discontinuous material and the free damping layer on the input power flow and the transmitted power flow are discussed. The conclusions provide theory basis for structural optimization design and reducing noise and vibration

POSTBUCKLING OF RECTANGULAR PLATES UNDER UNIAXIAL COMPRESSION COMBINED WITH LATERAL PRESSURE

Based on the nonlinear large deflection equations of von Karman plates, the lateral pressure is first converted into an initial deflection by Galerkin method, the postbuckling behavior oj simply supported rectangular plates under uniaxial compression combined with lateral pressure is then studied applying perturbation method by taking deflection as perturbation parameter.Two types of in-plane boundary conditions and the effects of initial geometric imperfection are also considered. It is found that the theoretical results are in good accordance with experiments.

LARGE DEFLECTION PROBLEM OF CIRCULAR PLATES WITH VARIABLE THICKNESS UNDER THE ACTION OF COMBINED LOADS

By using the modified iteration method of large deflection theory of plates with variable thichness[1], we solve the problem of circular plates with variable thickness subjected to combined loads under the boundary conditions of the clamped edges and get comparatively more accurate second-order approximate analytical solution. If the results of this paper are degraded into the special cases, the results coinciding with those of papers [1,2] can be obtained. In this paper, the characteristic curves are plotted and some comparisons are made. The results of this paper are satisfactory.

Modified fixation for periprosthetic supracondylar femur fractures:Two case reports and review of the literature

BACKGROUND Periprosthetic supracondylar femoral fractures(PSFs)present a challenge in terms of optimizing fixation in patients with poor bone quality.Surgical treatment and peri-operative management of PSFs in the elderly remain a burden for orthopedic surgeons.Among different treatment options,locking plate(LP)and retrograde intramedullary nail(RIMN)have shown favorable results.However,reduced mobility and protected weight-bearing are often present in the postoperative older population.With a purpose of allowing for early weight-bearing,a modified nail plate combination(NPC)was redesigned for PSF management.CASE SUMMARY In our cases,two elderly osteoporotic female underwent total knee arthroplasty(TKA),and then suffered from low energy trauma onto their knees after falling to the floor.Plain radiographs or computed tomography scans demonstrated oblique or transverse PSFs,both of which occurred at the distal femur above TKA.The modified NPC technique was performed for treatment of PSFs.The patient was made foot flat weight bearing in 1 wk.At 6-mo follow-up,the union was ultimately achieved using modified NPC with satisfactory implant outcomes.CONCLUSION Neither LP nor RIMN alone may provide adequate support to allow for union in circumstances where the patient has severely osteopenic bone.Therefore,developing a modified implant offer an alternative choice for treating PSFs.These two cases revealed that this technique is a viable option for the geriatric osteoporotic PSFs,offering safe,early weight bearing and favorable clinical outcomes.