热熔自攻丝夹具的合格支撑间距探究

为研究热熔自攻丝夹具的合格支撑间距,以6k21和6061铝合金板件为研究对象,测试100 mm×40 mm板件两端无夹紧点、100 mm×40 mm板件两端有夹紧点和300 mm×120 mm板件两端无夹紧点3种不同的情况,得到不同厚度板件在不同支撑间距下的形变量。进行力学试验,验证板件形变量与力学性能的关系。结果表明：板件形变量增大,其力学性能会下降;通过设置夹紧点以及增大板件尺寸可以减小板件的形变量;对于小尺寸板件,若支撑间距大于40 mm,应该添加夹紧点;大尺寸板件的最大合格支撑间距可以设置为80 mm,且不需要设置夹紧点。试验结果可以为热熔自攻丝板件夹具的设计提供参考。     

Biocompatibility of Tri-block Bone-matrix Material in vitro

To evaluate the biocompatibility of poly（lactic acid/glycolic acid/ asparagic acid-copolyethylene glycol）（PLGA-[ASP-PEG]） tri-block copolymer in vitro, L929 fibroblast was co-cultured with the copolymer for cytotoxicity, hemolysis and pyrogen tests. And, compared with PLGA, the adhesiveness rate of the copolymer was calculated. The experimental results show that the toxicity gradation of the material was 0-1; L929 fibroblasts had a good cell morphology and proliferated rapidly on the surface of the material; hemolysis ratio was 3.08%; there was no pyrogen reaction. The adhesiveness of PLGA-[ASP-PEG] was better than that of the PLGA＇s（P〈0.05）. The results confirm that the PLGA-[ASP-PEG] has a good biocompatibility.     

原始间隙对热熔自攻丝接头质量的影响

由于车身制造装配等存在误差,两板件贴合会出现原始间隙。为研究原始间隙给热熔自攻丝带来的影响,以厚度为2.0 mm的6K21和厚度为3.0 mm的6082-T6铝合金板为对象,研究工艺参数与板间间隙之间的关系,以及如何调整工艺参数来减小原始间隙带来的影响,并通过接头的力学性能进行验证。以板间间隙与最大试验力为研究指标,运用控制变量法、origin拟合得出以下结论:轴向下压力、拧紧扭矩在一定范围内与板间间隙呈线性负相关;原始间隙会降低接头的连接质量,通过增加10%～20%的轴向下压力或者20%左右的拧紧扭矩可减弱原始间隙带来的影响,提高连接质量。