A fabrication history based strain-fatigue model for prediction of crack initiation in a radial loading wheel

A strain-based fatigue model concerning fabrication history is applied to predict the fatigue life of a commercial car wheel under radial loads. As the prior conditions, the strain fatigue testing is performed on standard specimen of DP590 and FB540 steels at various fabrication states, including raw materials, pre-strain and pre-strain + bake. Furthermore, the strain distribution of car wheel during its rotation under radial loads is simulated via ANSYS. The fatigue properties mainly determined by crack initiation of car wheels at various fabrication states are predicted via local stress–strain method, in which the scale and surface factors are also taken into account. The radial fatigue testing is carried out, and the results are used to validate the present model. The fracture mechanism is analysed using FEI Nova 400 field emission gun scanning electron microscope

A study of charged kappa in J/ψ→K±Ksπ∓π0J/\psi \to K^{\pm} K_s \pi^{\mp} \pi^0

Based on $58 \times 10^6$ $J/\psi$ events collected by BESII, the decay $J/\psi \to K^{\pm} K_s \pi^{\mp} \pi^0$ is studied. In the invariant mass spectrum recoiling against the charged $K^*(892)^{\pm}$, the charged $\kappa$ particle is found as a low mass enhancement. If a Breit-Wigner function of constant width is used to parameterize the kappa, its pole locates at $(849 \pm 77 ^{+18}_{-14}) -i (256 \pm 40 ^{+46}_{-22})$ MeV/$c^2$. Also in this channel, the decay $J/\psi \to K^*(892)^+ K^*(892)^-$ is observed for the first time. Its branching ratio is $(1.00 \pm 0.19 ^{+0.11}_{-0.32}) \times 10^{-3}$.Comment: 14 pages, 4 figure

Direct Measurements of Absolute Branching Fractions for D0 and D+ Inclusive Semimuonic Decays

By analyzing about 33 $\rm pb^{-1}$ data sample collected at and around 3.773 GeV with the BES-II detector at the BEPC collider, we directly measure the branching fractions for the neutral and charged $D$ inclusive semimuonic decays to be $BF(D^0 \to \mu^+ X) =(6.8\pm 1.5\pm 0.7)$ and $BF(D^+ \to \mu^+ X) =(17.6 \pm 2.7 \pm 1.8)$, and determine the ratio of the two branching fractions to be $\frac{BF(D^+ \to \mu^+ X)}{BF(D^0 \to \mu^+ X)}=2.59\pm 0.70 \pm 0.25$

Measurements of the observed cross sections for e+e−→e^+e^-\to exclusive light hadrons containing π0π0\pi^0\pi^0 at s=3.773\sqrt s= 3.773, 3.650 and 3.6648 GeV

By analyzing the data sets of 17.3, 6.5 and 1.0 pb$^{-1}$ taken, respectively, at $\sqrt s= 3.773$, 3.650 and 3.6648 GeV with the BES-II detector at the BEPC collider, we measure the observed cross sections for $e^+e^-\to \pi^+\pi^-\pi^0\pi^0$, $K^+K^-\pi^0\pi^0$, $2(\pi^+\pi^-\pi^0)$, $K^+K^-\pi^+\pi^-\pi^0\pi^0$ and $3(\pi^+\pi^-)\pi^0\pi^0$ at the three energy points. Based on these cross sections we set the upper limits on the observed cross sections and the branching fractions for $\psi(3770)$ decay into these final states at 90% C.L..Comment: 7 pages, 2 figure

Measurements of the observed cross sections for e+e -> exclusive light hadrons containing K^S_0 meson at \sqrt{s} = 3.773 and 3.650 GeV

By analyzing the data sets of 17.3 pb$^{-1}$ taken at $\sqrt s= 3.773$ GeV and of 6.5 pb$^{-1}$ taken at $\sqrt s= 3.650$ GeV with the BES-II detector at the BEPC collider, we measure the observed cross sections for the exclusive light hadron final states of $K_S^0K^-\pi^+$, $K_S^0K^-\pi^+\pi^0$, $K_S^0K^-\pi^+\pi^+\pi^-$, $K_S^0K^-\pi^+\pi^+\pi^-\pi^0$, $K_S^0K^-\pi^+\pi^+\pi^+\pi^-\pi^-$ and $K_S^0K^-\pi^+\pi^0\pi^0$ produced in $e^+ e^-$ annihilation at the two energy points. We set the upper limits on the observed cross sections and the branching fractions for $\psi(3770)$ decay to these final states at 90% C.L..Comment: 6 pages, 1 figur

Optimal Design and Experimental Investigations of Aluminium Extrusion Profiles for Lightweight of Car Bumper

The present study aimed at developing an aluminium car bumper unit to replace the steel ones by using optimization based on experimental and FEM simulation results. The topology optimization method and response surface methodology (RSM) were applied in order to achieve an optimized design for the cross section of the crossbeam and the crash box, respectively. The three-points bending test and crash test for bumper unit were simulated to evaluate the optimization processes. The 6061 and 6063 aluminium alloy bumper unit has a weight reduction of 67% compared to the steel ones. The new extrusion dies were manufactured to produce profiles for the crossbeam and the crash box, respectively. Then the optimized extrusion profiles of crossbeam and crash box were verified by experimental studies. The performance tests were arranged to validate the experimental product. The mechanical properties of extruded aluminium crossbeam and crash box can satisfy the design requirements of products. The results indicate that the new designed unit can change the whole design of automotive parts for crash energy absorption, and definitely contribute to drastic weight reduction of steel parts.</jats:p