var svg = d3.select("div.div1").append("svg")
    .attr('width', width)
    .attr('height', height)

 simulation = d3.forceSimulation()
    .force('link', d3.forceLink()
        .id(function (link) { return link.id })
        .distance(function (link) { return link.propertyObj.distance })
        .strength(function (link) { return link.propertyObj.strength })
    )
    .force('charge', d3.forceManyBody().strength(-45))
    .force('center', d3.forceCenter(width / 3, height / 1.90))

       d3.selectAll("svg > *").remove();

      simulation.nodes(nodes).on('tick', ticked);
      simulation.force("link").links(links);

d3.selectAll("svg > *").remove();